The Rudall & Rose Patent Head

This "work-in-progress" aims to investigate the Rudall & Rose Patent Head, designed and marketed by that leading 19th century flute company. This head attempted to deal with the wide range of pitches which might have been encountered in this time, firstly by providing a very long tuning slide (extendable by 30mm and therefore by about 30 Hz) and secondly, by automatically moving the stopper at the same time as extending the slide, to keep the two in their most harmonious relationship.

We will attempt to identify the reasons why the head was thought to be needed, how it worked, how well it worked and what it can tell us about the flute of the time. While our investigation proceeds, here are a few images and notes to dwell upon ...

The Rudall & Rose Patent Head under examination.
See Clinton 1851 Flute to see the head in conjunction with the flute it is associated.

Note:

• The cap, at extreme right, rotation of which simultaneously extends the tuning slide while moving the stopper at a different but appropriate rate

• The crack through the embouchure, the inevitable result of shrinkage of a wooden head lined with unyielding metal

• some damage to the cap, probably by dropping.
  

The Entrails ...

From the top (enumerated from left to right):

Line 1: brass anti-rotation key (1) and the copper head liner (2) 

Line 2: the head (2) with its two end rings

Line 3: the inner slide, silver sleeve, barrel top ring, and barrel 

Line 4: screws to secure flange to top of head (1), flange (2), screws to secure cap to disc (3), screws to secure boss to top of inner slide (4), pin to secure disc to shaft (5), ring for lower end of barrel (6)

Line 5: embossed cap (1), brass ring to strengthen top of head (where screws secure flange) (2), steel shaft (3), boss (4), disc (5), stopper (6).

Operation

Rotating the cap (L5-1) rotates the disc (L5-5) attached to it by screws (L4-3). The disc is pinned (L4-5) to the shaft (L5-3) which rotates in the flange (L4-2). The flange is secured by screws (L4-1) which pass through the ring (L5-2), the top of the head (L2) and the top of the head liner (L1-2).

The shaft has two threaded sections with different rates. The larger, faster section drives a boss, (L5-4) secured in the top end of the inner slide (L3-4) by three screws (L4-4). The thinner, slower end section engages with and drives the stopper (L5-6). The stopper takes the form of a cylinder of brass with a flange near its centre. The flange is threaded to take the shaft. A silver disc is attached at the embouchure end, and the outside of the cylinder is covered with cork to seal the bore.

As the shaft rotates, it moves the inner slide at a high rate, and the stopper at a slower rate.

Things to note in the image above:

• the anti-rotation key is normally riveted to the copper inner slide and locates in a slot just visible in the end of the copper head liner. In this case, like many others, the key has been torn off by an attempt to contra-rotate head and barrel in the normal way. Patent heads can only be operated by rotating the cap.
• The barrel, barrel top ring, silver sleeve and inner slide are clearly separate items, but are not easy to disassemble. The far end of the inner slide flares into the socket region of the barrel and is thus unable to be removed unless the silver sleeve can be removed or unless the flared section is bored out. The silver ring was probably applied next, followed by the silver sleeve - a firm drive fit on the slide and thus difficult to remove. There were no compelling reasons to proceed further in this area.
• The silver plating inside the copper inner slide is in very good condition where it was protected by the location of the stopper. Below that it can be seen to be very tarnished.
• Only partly distinguishable in the image is the considerable damage to the top of the silver sleeve on the copper inner slide. This damage was caused by the anti-rotation key, torn from its normal position on the slide, and repeatedly forced against the top of the sleeve by further attempts to separate the slides.
• The inside of the flange at L4-2 is covered by a thick, gummy substance, possibly a degraded grease intended to lubricate the shaft which passes through it.
• The disc, flange, boss and stopper have all had any surplus material removed by turning, presumably in an attempt to shed unnecessary weight.

The Engine

To make the operation a little clearer, here is an image of the inner active parts separately assembled. From left to right:

1. cap, secured to disc by two screws

2. pin that secures disc to shaft which links remaining items

3. disc, driven by cap

4. flange in top of head through which disc passes

5. boss in top of inner slide and which drives inner slide

6. stopper

What actually happens?

The table below shows that the distance from the centre of the embouchure to the face of the stopper decreases by 5mm as the slide is extended from fully in to its maximum extension of around 30mm.

If you have information to add about the Patent Head, or questions you'd like us to try to answer, please contact us.

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