William Painter Bottle Stopper

U.S. Patent Number: 327,099           Patented: September 29, 1885

William Painter’s patent application was filed June 5, 1885 and specified:

I, William Painter, of BaltimoreMaryland, have invented a new and useful Improvement in Bottle-Stoppers…particularly designed for use with bottles or similar vessels containing fluids under pressure from effervescence or otherwise; but it is adapted as well for use where such pressure does not exist.

Stoppers have heretofore been made secure against internal pressure in one of two ways – by mechanical means exterior to the bottle, as by using a tie-wire, also by special stopper-fasteners, which have been made in large variety; or by placing the stopper inside the bottle and so arranging it that the stopper is forced against a seat or packing by the pressure within. 

The first of these methods is objectionable because of the expense, and in some cases the inconvenience of its use and liability of accidental opening.  The second is so for the same reasons, and for the additional one that the presence of the stopper inside of the bottle is an obstruction to ready and effectual cleansing both of the bottle and stopper.  Stoppers secured by external fastenings are retained solely by the power of the device to overcome the internal pressure.  Those within the bottle are retained because they present a solid mass too large to pass through the bottle-neck.  In neither case referred to does the lateral expansion of the stopper itself against the interior of the bottle-mouth enter as an element of its action in resisting internal pressure, as it does with stoppers made according to my method.

My invention differs from all others in the respects named.  It is made of thin material, and placed within the bottle neck or mouth in cup-shaped form, with its convex side inward, so that it presents the resistance of an inverted arch or dome having its haunches supported by contact with the walls of the bottle-mouth, which are preferably indented or grooved to afford a more secure hold.  Pressure upon an arch is always transferred in part as lateral pressure against its abutment, while a similar pressure upon a solid body having the same convexity does not tend to displace the abutment laterally, but to shear off the edges of such solid body.  This physical principle illustrates the actual difference between my cup-shaped disk-stoppers and all others with which I am acquainted.

In the accompanying drawings, Figure 1 is a perspective of an ordinary bottle with my stopper inserted.  Fig. 2 is a vertical section of the bottle neck and stopper.  Figs. 3 and 4 show methods of removing the stopper.  Figs. 5 and 6 illustrate the difference in action between my inverted-arch stopper and an ordinary internal stopper.  Figs. 7, 8, and 9 are modifications of the invention.

A is an ordinary bottle with a slight internal groove, b, within the neck near the top, and C is the disk-stopper in place.  I prefer to provide the bottle-neck with a groove, because it makes the action of the stopper sure, notwithstanding the usual internal variation is sizes of necks incident to the manufacture of bottles, and also of any variations there may be in the material from which the disk-stoppers may be made, but the groove need not be more than one-sixty-fourth of an inch in depth.  Were it practical to secure uniformity in the respects named, the groove would not be required, and it may be dispensed with, as shown in Figs. 7 and 8.  With comparatively low internal pressure the groove is not necessary in any case.

The stopper C is a circular disk of some suitable flexible material.  It may be normally somewhat concave, but the flat form answers the purpose best.  The disk is made considerably larger than the neck of the bottle, so that when it is forced therein its edges are contracted and it assumes the form of an inverted arch or dome supported by pressure against the internal walls of the bottle-neck…and will cause the resistance of the stopper to increase measurably in proportion to the pressure upon it up to that point at which the arch will be crushed.

If the stopper is made from material having considerable resilience or inherent expansive force, or if the interior of the bottle-mouth be roughened, sufficient adhesion will result without the use of a groove to secure the initial hold…

For general purposes two-ply rubber packing of common quality answers well for making the disks.  The material known as “linoleum” (made principally of ground cork) also serves an excellent purpose, and is still cheaper than rubber packing.  Many other materials, metallic as well as non-metallic, are available…Metal disks require great strength of bottle-neck to avoid breaking, and are therefore not considered as desirable…

To remove my disk-stoppers, a simple wire hook, k, as shown in Fig. 3, may be employed.  The point pierces the disk and either forcibly reverses the arch or lifts up one edge, thereby releasing the disk.  To facilitate the piercing of the disk, a pit or cavity, g, extending part way through the disk may be employed.  By simply applying pressure against one edge of the disk, so as to force it inward and tilt or partially rotate it, its hold is released, when the internal pressure causes it to fly out.  This action is shown in Fig. 4…

When a groove in the bottle-neck is employed, the concave form shown in Fig. 2 is preferred…

It is sometimes desirable to remove the disk-stopper from the bottle without the use of a tool.  In such cases I form the disks with a lug or ear, q.  (Shown in Figs. 5 and 9.)  A slight pull on the ear starts the disk from its position, and it is thus easily removed.  I may also attach to the disk an eye of wire, like the shank of a button, or a string, cord, or other device to facilitate its removal; but for general use the simple circular disk is preferred…

By my method of sealing bottles against internal pressure, as described, I am enabled to produce stoppers with the least possible quantity of material, and that of a very cheap kind.  The stoppers require simply to be cut from a sheet by a hollow punch or a punch and die.  They can therefore be produced at a small portion of the cost of any other stopper I have knowledge of, and require no fastenings of any kind, as they are self-retaining.  They are easily and quickly extracted, are neat in appearance, and leave the bottle and its mouth entirely clear of all obstructions.

A great saving of bottles results from the use of my disk-stoppers.  They are extremely cheap, and when bottles are lost or broken the cost of the bottles alone is sacrificed, which is not the case when any of the usual forms of fastening are employed.  Moreover, by reason of the uniformity of the material employed a perfectly tight seal is always secured, and the contents of the bottle cannot become flat. 


William Painter’s “Bottle Seal” patent (commonly referred to as the “Baltimore Loop Seal”) is included in this review because his particularly well-written specifications detail the engineering principles supporting the stopper’s functionality.  Included are several clues portending the success he would ultimately achieve with his Crown Closure.  Although they are often confused with Hutchinson bottles, Baltimore Loop Seal bottles are easy to identify because of the horizontal groove inside the mouth, and a generally smaller, tapered opening. 

Baltimore Loop Seals were successfully marketed to bottlers across the North American continent who utilized them for bottles containing "still" beverages, such as beer.  They were not adopted for the bottling of carbonated beverages such as soda and mineral water. 

The accompanying 1886 Bottle Seal Company National Bottlers’ Gazette advertisement nicely illustrates how the stopper worked.  Note the rubber-handled “opener, used as a temporary stopper when contents are but partly used.” 

For additional information about Baltimore Loop Seals, visit Bill Lindsey's Historic Glass Bottle Identification & Information Website.  In addition to Bill's very descriptive material, note the posted link to a well-written, "e-published" article entitled "William Painter's Baltimore Loop Seal" co-authored by Bill Lockhart, Tod von Mechow, Beau Schriever, David Whitten, Bill Lindsay, and Carol Serr.  Here's a link to the Baltimore Loop Seal portion of the Historic Bottle Website: Loop