Rudall & Rose's Patent Head Specification

A.D. 1832 .  .  .  .  .  .  . No 6338



These days, with pitch firmly locked down to A440 Hz, (plus maybe another 2 or 4Hz to allow for fickle fashion!) we can find the ideal location for the flute stopper and forget about it.  No such luxury applied in first half 19th-century England.  Pitch could be anywhere from around A410 to A455.  The very long tuning slides of the period are a reminder of this.  But when you have to adjust the slide far enough to cover that range, you really need to move the stopper too, or the third octave tuning goes awry.  And that has an effect on low octave performance and tone.  Several makers had come up with ways to help the player keep slide and stopper appropriately synchronised - a good example would be Ward's Patent Terminator and Indicator.  Rudall & Rose went one step further.  They automated the process. 

In 1832, Rudall & Rose lodged their first patent, for a remarkable piece of 19th century engineering, their "Patent Head".  Essentially, they linked the stopper and the slide to the cap via a two-speed screw.  As the player turned the cap to adjust the slide, the stopper moved too, but at a different rate.  The pitches of the two-speed screw maintained the optimum stopper-to-embouchure distance over the range of slide available. 

In this article, we delve into the patent.  Like all patents of the time, it starts off with the usual litterae patentes guff.  "To all to whom these presents shall come, greeting..."  I've not bothered with the formalities, but picked up at the substantive matter.  I've also made a few changes to punctuation to improve its readability, and added a few comments in [square brackets]....

The specification

Our improvements on or in the construction of flutes have, for their object, a mode of elongating or contracting the flute for the purpose of varying the pitch or tune of the instrument, and of shifting the situation of the cork or stopper simultaneous, and in due proportion to the increased or diminished length of the flute when so adjusted, by which contrivance the flute may, with the utmost facility, be brought into unison with another instrument, the tune of which may happen to be either above or below concert pitch.

The objects of the improvement above described may be effected by different mechanical means applied either within the flute or externally.

The mode which we find best suited to the purpose is shown in the accompanying Drawings, where Figure 1 represents a portion of a flute to which the improvements are adapted. Figure 2, is the same, shown partly in section for the purpose of exposing to view the internal sliding tube. Figure 3 is a further section of the same, the tubes being cut longitudinally through the middle to exhibit the mechanism by which they are to be moved.

Figures 1,2 & 3

[Note, in Figs 2 & 3, there are a pair of screws shown which are presumably intended to secure the decorative silver sleeve and perhaps the guide strip k to the body of the barrel section and the slide inside.  I have not seen such screws on a Patent Head; presumably other ways to achieve these ends were found.]

Figure 4 represents a shaft with two screws a and b, the threads of which pass round the shaft with different degrees of obliquity, (that is to say,) the one is a quick, the other a slow screw. The disc c is to be securely fixed by a pin to the upper end of the shaft as a thumb-piece, by which the shaft may be turned round.

Figures 4 & 5

Figure 5 exhibits the screw shaft and its appendages connected together, and attached to the sliding tube d, d, and to the cork or stopper e, but shown in this Figure detached from the flute.

The same parts will be seen in section, and in their working positions within the flute in Figure 3.

[Note: Because the scale of the image is too small to make out these details adequately, I have prepared the close-up below.  It is from Figure 3, and takes us from the cap down to halfway through the embouchure hole.

As an aside, it is an opportunity to marvel at the remarkable detail Malby & Sons managed to achieve in their drawing.  The approximately life-sized image, "drawn on stone", has managed to survive lithography, storage for 154 years, photocopying, scanning, zooming and my ham-fisted attempts at photo-editing out the ravages of time.  And still tell us exactly what we need to know.  Enjoy particularly the perspective on the multi-start buttress thread lead-screw a.  Bravo Mr Malby! 

Now, back to the patent....] 

Detail from Figure 3.

At the upper end of the top joint of the flute, the fulcrum piece f is fixed by pins passed from the outside. Through a central hole in this fulcrum piece, the neck or upper end of the screw shaft a protrudes, and the shaft is held in that situation by the disc c being pinned or otherwise fastened on to its end, as before described, which allows the screw shaft to turn round freely when moved by the thumb piece e.

In the upper end of the sliding tube d a screw box g is securely fixed, and through this box the shaft passes, and in it the large screw a works; hence on turning the shaft the screw box g and sliding tube d will be moved upward or downwards, and the flute consequently be shortened or elongated. The cork or stopper e has a bridge or disc h fixed within it with a hole in the centre, in which the lesser screw b works; and as the shaft is turned to move the sliding tube up or down, the cork or stopper is simultaneously moved also nearer to or further from the mouth hole a certain distance proportionate to the varying length of the flute, so as to regulate with great accuracy the pitch or tune of the instrument.  A cap i, having a milled edge, may be affixed to the disc or thumb piece e, for the convenience of turning the screw shaft, by which the whole of the working parts will be concealed from view. A rib k is placed on the side of the tube for the purpose of guiding the tube d as it slides, and preventing its turning round; but that object might be effected equally well by placing a guide elsewhere.

[This rib appears to be visible in Figure 1.  In Patent Heads I have seen, it is replaced by a rib hidden inside the head section.]

It may be desirable to add that the threads of the screw shaft a and b should be so formed that while the tube d is sliden [!] a distance of one inch and a quarter [31.75mm], the cork or stopper e should be moved a distance equal to three sixteenths of an inch [4.76mm] or thereabouts.

[We then lapse back into formality, but I'll include it for the dates.  Note that although the patent was lodged in 1832 and bears that date in the title, it doesn't get signed until the following year, and doesn't get printed until the Patent Office does a big cleanup in 1857.  Those familiar with the Circumlocution Office in Charles Dicken's "Little Dorrit" will already be smirking.]


In witness whereof, we, the said George Rudall and John Mitchell
Rose, have hereunto set our hands and seals, this Twenty-fifth day
of May, in the year of our Lord One thousand eight hundred and



AND BE IT REMEMBERED, that on the Twenty-fifth day of May, in the third year of the reign of His present Majesty King William the Fourth, the said George Rudall and John Mitchell Rose came before our said Lord the King in His Chancery, and acknowledged the instrument aforesaid, and all and every thing therein contained and specified, in form above written. And also the instrument aforesaid was stamped according to the tenor of the Statute made in the fifty-fifth year of the reign of His late Majesty King George the Third.

Inrolled the Twenty-fifth day of May, One thousand eight hundred and thirty-three.


Printers to the Queen's most Excellent Majesty. 1857.


The grant of patent would ensure no-one could copy it for at least 14 years, thus giving Rudall & Rose a monopoly up to 1846.  I can't bring to mind any similar device after that period, so I don't think it probably warranted the cost and effort of seeking the patent in protection terms.  It may well have repaid the effort in status terms.

A good number of Patent Heads are to be seen still, although their greater complexity and heavy weight are significant drawbacks to use today, given that most of us no longer need to move the stopper in regular tuning, and indeed, may wish to custom tune the stopper cavity for our purposes.  But it remains a remarkable piece of work to be marvelled at.

To see what lurks inside the head in physical form, see: The Rudall & Rose Patent Head


Thanks to the British Patent Office for keeping safe custody of this document for our benefit and enjoyment.


Back to McGee-flutes Index page...

  Created: 14 October 2011