User:Montanabw/Dr. Bristol (Horse Bit)

This may be a notable horse bit, but so far the entire article is based on existence of a patent, which is a primary source. Have reliable, independent sources (like reputable magazines, journals, books or newspapers) discussed this horse bit?

Further, sections like the "Controversy" paragraphs do not cite any sources, making them appear as prohibited original research. Make sure that every substantive claim that might be challenged is accompanied by a footnote-style reference. Thanks, /wia 🎄 /tlk  16:17, 15 December 2015 (UTC)}}

Introduction
The horse bit known as the "Dr. Bristol" was the invention. of a certain J.S. Bristol, purported to have been a dentist. The bit is characterized in that it contains a double jointed bit mouthpiece of three components with the central component comprising a flat plate. The lengths and widths of the plate vary between examples, but in its original form, the plate was intended to be of sufficient length that it could lie across the whole width of the horse's tongue. Bristol insisted that this bit was intended to be comfortable for the horse because the central plate would lie flat onto the tongue thus lowering the pressure.



Analysis of the orientation of the bit
The joints of the mouthpiece are similar to those of a chain-link. Connecting loops (labeled B2 in the figures of the patent) on the side parts (or "cannons", feature B in the original patent), link with holes through the plate (feature α in the patent) so that if the mouthpiece were stretched out the axes through the loops of the side parts will lie at 90 ° to the axes through the holes in the central plate. One of the original characterizing features of the Dr. Bristol is that the angle between the axis passing through the bore (feature b in the patent) at the distal (outward) end of the cannon (the bore axis, BA) and a line lying in the plane of the plate that is directed across its width (FL) must be such that the correct orientation of the plate is achieved when the reins are tensioned.

In most examples of the Dr. Bristol this angle, FA, is around -45 ° as viewed from the left hand side of the bit.

This orientation of the plate with respect to the bore axes is important for bringing the flat aspect of the plate into almost parallel alignment with the horse's tongue when the reins are tensioned, as required by the original design.

The angle between the bore axis and the line along the tongue when the reins are tensioned, WA, must be such that when it is added to, or subtracted from, FA, the resulting angle should be close to either 0 or 180 degrees. This is the angle between the feature and the plane of the tongue.

Controversy
The action of the Dr. Bristol has been a topic of controversy with many popular texts describing it as having a harsh action due to the plate's edge orientation to the tongue. The correct analysis shows that such an action is only possible if the bit is placed into the mouth such that the feature angle, as defined from a left hand side view, is +45 °. In this sense the bit might be used in two different ways, one such that the plate lies flat to the tongue and is 'mild' (FA = -45 °) and the other such that the plate lies edge-on to the tongue (FA = +45 °) and is 'harsh'.