H.G.Co. Petticoat Beehives
by H.G. "Bea" Hyve

Reprinted from "Crown Jewels of the Wire", December 1995, page 13

SOME STATISTICS

The insulator under discussion here is made of glass and is of a rounded conical shape. (See Figure 1) Variations aside, it has a 3-1/4" diameter at the base, is just short of 4-1/4" tall, and weighs 1-1/4 pounds. The embossing is on the skirt front ("H. G. CO. ") and back ("PETTICOAT"), and there can be skirt and crown letters. These beehives come in almost every insulator color, and are usually regarded as communication insulators only.

Figure 1

Poetry in glass... 
the H. G. CO. PETTICOAT beehive 
Shown actual size
 (Courtesy of Chris Hedges)

THE DEVELOPMENT OF THE "BEEHIVE" DESIGN

Very early telegraph insulators were hardly more than glass cups which sat upside-down on a wooden peg. Although they presented several problems, they were the beginning of an industry that would last well over a century; down to our day. Hundreds of improvements were made in insulator designs throughout the years, in various attempts to find a better insulator. 

Probably the greatest beneficial effect on the industry was the invention of a screw-threaded cavity (threaded pinhole) for insulators by Louis A. Cauvet. He was granted letters Patent No. 48,906 on July 25, 1865. (See Figures 2 and 3) This innovation allowed for insulators to be screwed onto a matching screw-threaded pin, eliminating countless problems. This was the first link in the chain of events leading to the creation of the H. G. CO. PETTICOAT beehive.

This patent was reissued on February 22, 1870. (See Figures 4 and 5) A patent reissue is allowed when it is proved that language in the original did not in some way convey the proper meaning. There are a number of slight changes, and the exact reason for the reissue isn't known; but there was a bitter legal battle between Brookfield and Homer Brooke over the thread patent during those years. The request for the reissue could have stemmed from that. 

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Figures 2 and 3 

Letters Patent No. 48,906 
by Louis A. Cauvet 
(Courtesy of N.R. Woodward and Elton Gish)

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Figure 3

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Figures 4 and 5 

Reissue of Letters Patent No. 48.906 
by Louis A. Cauvet 
(Courtesy of N.R. Woodward and. Elton Gish)

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Figure 5

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Figures 6, 7, and 8

Letters Patent No. 122,015
by Robert Hemingray
(Courtesy of N.R. Woodward and Bill and Jill Meier)

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Figure 6 (cont'd)

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Figure 6-1/2

Company ad from 
Williams' Cincinnati Directory and Business Advertiser
1871
 (Courtesy of Glenn Drummond)

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Figure 7

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Figure 8

The second link was formed on December 19, 1871, when Robert Hemingray was issued letters Patent No. 122,01 5 for "a new and useful process in molding telegraph insulators". (See Figures 6, 7, and 8) It dealt primarily with the forming of the cavity of the insulator, by first forming the wider unthreaded portion, then forming the threaded deeper portion. However, of more significance than the two separate operations in forming the skirt and pinhole, was the "yielding collar" . It formed the area just below the thread, and also compensated for variations in the amount of glass in the mold by increasing or decreasing the length of the skirt. We have all seen some pieces where there was altogether too much glass and hardly any skirt at all. This press feature is opposed to the Brookfield presses of that era that made the thing collectors call "swirl-start" threads, where the mandrel was screwed into the hot glass, and there was nothing to form a definitive boundary between the base of the thread and the skirt. 

The third link in the chain was forged by Samuel Oakman with his invention of the double petticoat*, for which he received letters Patent No. 288,360 on November 13, 1883. (See Figures 9 and 10) (The petticoat design had been around since the October 15, 1872, patent by Oakman, but that had dealt mainly with construction details of the plunger for making the segmented threads, and the patent was for a recess to hold paraffin. Although we have no proof of when these particular insulators were made, it does seem that they were made prior to 1883, and the prominent mention of the paraffin recess along with the double petticoat was an attempt at belated patent coverage of a feature that had been used for some time. The only connection to earlier patents is that some of the Oakman insulators that bear the date of the October 15, 1872, patents also have double petticoats.)

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* Insulators are correctly referred to as "double petticoat" even though the outer surface is actually the skirt. But the term "double petticoat" has become the "correct" word to use.

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Figures 9 and 10

Letters of Patent No. 288,360
 by Samuel Oakman 
(Courtesy of N.R. Woodward)

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Figure 9-1/2.

Newspaper article about new storeroom in the
Covington Daily Commonwealth 
February 1, 1881 
(Courtesy of Glenn Drummond)

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Figure 10

(Note paraffin recess "C")

Let's expand on this a bit to perhaps clarify it. In order to secure a patent on an item, it is necessary to represent a part of the construction of the item as being new and original. Oakman wanted to claim rights to the double petticoat, but without the paraffin recess, it could be correctly argued that the patent wasn't valid, because that feature had been used for some time prior. So, in the first section of his summary, he specifies the paraffin recess, while in the second section he leaves this out, and the text is written so that it would apply to any double petticoat insulator. This was an attempt to put the entire design through as a package deal. Evidently Oakman was successful, since his patent was used for many years as applying to the double petticoat feature. (The paraffin recess would not have been practical, was never used to any extent, and would have been a nightmare for glassmakers.) 

So, Samuel Oakman is generally credited with the invention of the double petticoat or inner skirt, used for the purpose of creating a greater non-conducting surface on the insulator. And Hemingray may have believed that he could not be held in violation for making double petticoat insulators so long as they did not have a paraffin recess, and he was, of course, correct in thinking that. (Interestingly, Oakman never referred to this feature as a petticoat or double petticoat. In his patent specs he calls it "a broad interior band of weather-protected surface for insulation between the exterior of the insulator and the supporting peg...". "Petticoat" is certainly easier and faster to write! However, the word "petticoat" was in use as early as 1888.) 

These three links, the patents by Cauvet, Hemingray, and Oakman, completed the chain of events necessary for the birth of the beehive. On February 12, 1884, about three months after the petticoat patent, Oakman was issued Design Patent No. 14,674 covering the beehive shape. (See Figures 11 and 12)* (A design patent is a totally different thing from a letters patent. The design patent relates to an exact and specific appearance of an article, rather than to any practical application. There are only a very few design patents relating to insulators. )

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* Figure 11 intentionally does not show interior detail, because that was not to be a part of the patent claim. The illustration has that narrow groove that belongs to those earliest Brookfield pieces with the 1870 date; later ones have a larger groove, not shaped to accommodate a wire with essentially no play.

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Figures 11 and 12

Design Patent No. 14,674 
by Samuel Oakman
 (Courtesy of N. R. Woodward and Elton Gish)

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Figure 12

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Figure 12-1/2

Company ad in the Covington City Directory 
1878 
(Courtesy of Franklin Jaquish and the Kenton County Public Library)

Again, Oakman did not call his new design a "beehive". This nickname, as well as a number of others that are used by collectors, was introduced by John C. Tibbitts in 1967. It was never used by manufacturers or anyone else prior to its introduction in his first insulator book that year. Listen to how Oakman describes his insulator in his patent spec. "Heretofore insulators have been made which presented, when viewed in elevation, an irregular and complicated form not pleasing to the eye. My design consists in having the insulator shaped so as to be a regular paraboloid, or so near to this form as to strike the eye as such. This regular paraboloidical surface is interrupted by a single equatorial groove." This "paraboloid traversed by an equatorial groove" is our beehive of today!*

More in Part 2 next month...