J. Casale - W2NI

Horace G. Martin

Centennial of the Martin Vibroplex

A classic Martin Vibroplex from the late teens
A classic Martin Vibroplex from the late teens.
This spring (May 2005) marks the one hundredth anniversary of the commercial introduction of the Vibroplex. I thought it would be appropriate at this time to document in more detail the activities of Horace Martin for the months and years leading up to this introduction. In particular, his undocumented experiments that ultimately developed into the Vibroplex. You might be interested to learn that in 1902 he gave his patent attorney drawings for an all mechanical transmitter that were never filed.

In 1900, Martin then 27, still working as a telegrapher, established his first shop at 75 Nassau St in New York City. He formed a partnership with fellow telegrapher, 29 year old Thomas J. Dunn, operating as the Dunn-Martin Electric Company. Together they did electrical contract work and built a medical shock device for the treatment of telegraphers suffering from telegrapher's paralysis. During this partnership, Martin was working separately on self-adjusting relays and various automatic telegraphy projects including the Phillips Automatic Telegraph System and a typewriter like keyboard transmitter.

One of Martin's earliest experiments with a "semi-automatic" transmitter was conducted at the Nassau St shop. The instrument used two ordinary Morse keys - one for sending dashes and another for sending dots. The "dot" key controlled a circuit consisting of a pair of electro magnets and a local battery. The armature on the electro magnets was connected to a long flexible pendulum. When the "dot" key was pressed, the armature pulled the pendulum against the magnet's cores where it was stopped abruptly causing it to go into vibration. A contact on the pendulum opened and closed a circuit until the armature was released and the speed was varied by placing an ordinary binding post at different positions on the pendulum. To send the letter "B," you close the "dash" key first then quickly press the "dot" key allowing the pendulum to generate three dots. Releasing the "dot" key caused the armature to drop and the pendulum was then arrested.

Martin conducted tests of this transmitter on the press wires of the New York World where he was working as a telegrapher. He was particularly concerned with the "carrying" capabilities on long lines. The facilities at the "World" gave him excellent opportunities to test all kinds of telegraph transmitters. He generally conducted his tests on the "World's" St. Louis wire in the middle of the night around 4:00 AM after he came off duty. His transmitter produced strong signals to St Louis, but he had problems with the trunnion seats for both the pendulum and the armature. This was the first experiment using a vibrating pendulum and Martin knew at this point and time that he could set a pendulum into vibration by moving it against a stop with his hand.

The partnership with Dunn lasted for two years. Dunn bought out Martin's share of the business and later went on to develop his own semi automatic transmitter called the Dunduplex. The model of Martin's early experiment was kept by Dunn in box of "junk" from the Nassau St days and still existed as of 1906.

In early 1902, Martin moved to Bridgeport, Conn. to work as an assistant for Walter Phillips at the American Graphophone Company. Martin continued his experiments at his residence in Bridgeport and developed his first commercial transmitter, the Autoplex. In September, he moved back to New York and rented shop space from Max Sanger, a model maker, located at 62 Cortlandt St. He filed for a patent on the Autoplex on October 6th and with Sanger's help, built and sold "several dozen" Autoplexes from this address. The Autoplex had reasonable success but was known to the telegraph fraternity as the "battery machine" because of its dependency on a local battery to drive its electro magnets. Martin almost immediately after filing for this patent started experimenting with ways to substitute the electro magnets with some kind of mechanical motor.

On November 13, 1902, Martin sent patent drawings to A.M. Wooster, his Patent Attorney in Bridgeport, Conn. for a new all mechanical transmitter that could be powered by a mechanical motor. Martin wanted him to apply for a new patent as an improvement on his Autoplex as soon as he could come up with the necessary funds. During the time he was developing these instruments, Martin was not always in a financial position to take out patents on every improvement, even with help of Walter Phillips. He asked Wooster how much it would cost to file for a caveat and/or a second patent. Wooster advised him not to waste his money on a caveat and just patent the invention but it would cost Martin about $85.00.

Horace Martin's 1902 patent drawing
Horace Martin's 1902 patent drawing of an
all-mechanical transmitter that was never filed.
Referring to Martin's hand written drawing in the article, the shaft of a toothed wheel is turned by any suitable means, such as kicks from a Clock's pendulum or a spring motor. The wheel is held in restraint by the key lever. Pressing the lever to the right releases the wheel permitting it to turn. The teeth of this wheel push a contact spring towards a fixed contact to produce dots. Pressing the lever to the left stops the wheel and further pressure extends the flexible portion of the lever causing the circuit to close for the duration of a dash. A model of this key was built in early 1903 but was unfortunately not preserved.

Martin experimented with two other ways to produce dots while at Cortlandt St. One experiment used a clock mechanism with a pendulum and another used a flywheel. He originally purchased an enclosed clock movement from Sanger with hopes of incorporating it in his Autoplex. But in early 1903 he used it in a separate model where a pendulum was carried by the escapement of the clock. When the clock mechanism was set in motion, the escapement caused the pendulum to oscillate back and forth opening and closing a circuit producing dots. He placed a weight at various points on the pendulum to see if it would produce firm signals at a uniform rate of speed. He also tried substituting the clock with a small toy hot air engine but had problems with it overheating.

In another experiment he mounted a small ratchet wheel on the same shaft with a flywheel. On one end of a centrally pivoted key lever were finger keys. On the other end was a rack which was normally held out of engagement of the ratchet wheel. Moving the lever to the right engages the rack into the ratchet wheel causing the flywheel to spin. The shaft had a contact that opened and closed the circuit as it spun around. Martin conducted several experiments like this using parts from one to build another.

In a second letter to Wooster dated Nov 29, 1902 Martin says he is "swamped in getting things going". What is notable in this letter is that Martin makes mention of developing a "Wireless Telegraph System". Wooster had asked Martin how the system was going and was very interested in learning more about wireless technology. Martin's reply was, "I expect to take up the system again in the near future and should I have a little luck in conjunction with a very pretty theory I suppose we will have to call on the patent office again." (Martin experimented for many years in wireless but no patents were issued.) Martin worked at Sanger's shop until June of 1903, and in addition to building the Autoplex and conducting experiments, he was perfecting the Phillips System and doing general electrical work such as repairing and wiring. The remaining months of 1903 Martin moved his shop to 53 Vesey St where he continued his experiments while still a telegrapher.

1904 was a critical year for Martin as an inventor. In February, the United Electrical Manufacturing Company was formed as a organized effort to market the Autoplex. Martin became the general manager of both sales and manufacturing and his 53 Vesey St. shop was upgraded. In the months preceding the formation of UEM, Martin was pre occupied with his experiments and let his guard down in anticipating the competition that was forming. In January of 1904, William Coffe, a telegrapher from Ohio, filed for a patent for an all mechanical, motorless transmitter called the Mecograph. In April of 1904, Martin inspected two transmitters manufactured by the Mecograph Company at their dealer's store in New York City. There were two Mecographs on display - one had a vertical pendulum, and the other had a horizontal pendulum "contained in a small metal case". Both were marked "patents pending".

The following month, on May 7,1904, Martin filed for his second transmitter patent as an improvement to his Autoplex that included one design for an all mechanical, motorless key. The patent was granted on August 9, 1904. (767,303) The earlier filing date by Coffe would come back to haunt Martin. Even though Martin is credited with inventing the art of "semi-automatic telegraphy" with his Autoplex, Coffe gets credit for inventing the first all mechanical motorless key. Martin was later criticized by Mecograph that this August 9th patent was a paper patent, that no practical instrument was ever produced from it and that it was hastily put together by Martin after seeing the two transmitters at Mecograph's dealer store in New York. Also, they thought the patent was granted quickly because of the limited scope of claims (3) made by Martin in his application. Martin's patent called for a lever that released a restrained vibrator to produce dots similar to what was in the Coffe patent. But Martin's one piece lever was productive in two directions - moving it to the right produced dots and to the left a dash. In Coffe's patent, the lever was productive in only one direction - to the right for dots. A separate dash lever made out of a leaf spring was attached to the side of the main lever. An operator pressed this lever to the left against the main lever to produce a dash. The patent office and subsequently the courts ruled this small difference in Martin's design "exhibits a patentable invention".

Martin used the period from August 1904 to early 1905 to develop the Vibroplex and prepare UEM's factory for its introduction. In a later law suit between UEM and the Mecograph Company, Martin's lawyers stated that the Vibroplex was not manufactured until "sometime in 1905". This is also evident in the trades for this period. One week after Martin was granted his August 9th patent a small business sketch about him appeared in the Telegraph Age on August 16, 1904. It credits Martin with receiving "patents" and highlights the Autoplex but nothing was disclosed about a new mechanical transmitter.

Models representing the 'Original' design 1905-1920
Horace Martin's "Original" design has changed little over the years.
The models above represent the years 1905-1920. ( left to right)
In January of 1905, UEM was still advertising the Autoplex and made no mention of the Vibroplex being available yet. On May 16, 1905, in another business notice, UEM, "owning to pressure", enlarges its operation at 53 Vesey St. Two large lofts in the building were now devoted for manufacturing. Among the products listed were the Martin Autoplex and for the very first time, the Martin Vibroplex. Also in this notice, an invitation was extended to inspect UEM's products at the Railway Telegraph Superintendents Convention to be held on May 17th at the Read Hotel in Chattanooga, Tenn. (a major trade show) Details of the convention show that a Martin Vibroplex was on exhibit and was "carefully looked into by all interested". This appears to be the very first public showing of the Vibroplex. UEM and at least one of their agents began advertising the Vibroplex the following month. Martin later filed for a patent that is truly representative of the Vibroplex on April 16,1906.

On Martin's early production models of the Vibroplex, his labels were stamped, "Patented August 9, 1904". The courts would later agree with Martin's reasoning for doing this by stating, "we are of the opinion that Martin conceived the particular instrument shown in the patent (August 9, 1904) and reduced it to practice before he began to manufacture it for sale."

Martin's Vibroplex affected the careers of thousands of telegraphers and radio operators for decades and is still used,admired and available today. Considering the endless stream of treasures from the attics of America showing up on Internet auctions, it seems likely that examples of his Vibroplex will still be around for a bicentennial celebration....

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Copyright (c) by John Casale - W2NI
Troy, New York


National Archives and Records Administration
New York, N.Y. U.S. Circuit Court of Appeals, Second Circuit
Horace G. Martin vs William Wall, Files #3067, Oct. 1907.
Benjamin F. Bellows vs United Electrical Manufacturing Co., Files # 3068, Jan. 1908
U.S Patent 812,183, William Coffe, Feb.13, 1906
U.S. Patent 767,303, Horace G. Martin, Aug.9, 1904
Letters, H.G. Martin and A.M. Wooster, Nov.13&29,1902.
Casale J., A Vibroplex in Every Telegraph Office, AWA, The OTB, May 2003, (Sources).