Ethan Allen's Patents
Patents related to handguns:
- 1837 Nov 11th - Patent 461 : Allen's very first patent describing the double action system used on his pepperboxes and pistols
- 1845 Apr 16th - Patent 3998 : (1) Simplified DA System, (2) Pitman system for barrel cluster rotation
- 1857 Jan 13th - Patent 16367 : (1) Fixing barrel cluster to the frame, (2) Combination trigger guard/loading lever, (3) nipple with a gas check valve
- 1857 Dec 15th - Patent 18836 : Rotating and locking the cylinder (Side-Hammer percussion revolvers)
- 1858 Sep 7th - Patent 21400 : (1) Anti fowling cylinderpin, (2) Gas deflection projection system for revolving rifles
- 1858 Nov 9th - Patent 22005 : Method of attaching the hammer to the outside of the case (Side-Hammer cartridge revolvers)
- 1860 Jul 3rd - Patent 28951 : Improved recoil plate to avoid jamming when cartridge expand
- 1861 Sep 24th - Patent 33328 : Locking mechanisms of (1) the cylinder pin, (2) the trigger guard, (3) the loading gate for the cylinder (lipfire revolvers)
- 1861 Oct 22nd - Patent 33509 : Improved cylinder locking system operated by the trigger
- 1865 Mar 7th - Patent 46617 : Case ejector system for the side-swing pistols
Patents related to rifles:
- 1860 Sep 18th - Patent 30033 : Dropping block rifle in general and the case-ejector in specific
- 1862 Apr 29th - Patent 35067 : The hinge pawl type action, and two improvements for the revolving rifle
- 1862 Oct 28th - Patent 36760 : Allen's Tang Sight
- 1865 Aug 22nd - Patent 49491 : Hinged breech double barrel shotgun
- 1868 Dec 15th - Patent 84929 : Improvement of the hinged breech double barrel shotgun
Patents related to bullets, cartridges and cartridge making:
Patent 461
It all started with this patent. It describes the mechanism for firing the pistol by simply pulling the trigger, thus eliminating the need to cock the hammer first. The trigger is connected to the hammer via a tumbler. By pulling the trigger the hammer gets cocked until the moment the tumbler releases the hammer. Under the pressure of the main spring, the hammer falls back to the initial position, causing the shot to be fired. This double action system was a true revolution for this time. The Tube Hammer pistol is the first gun to use the system and gives Ethan Allen his first commercial success. The same mechanism is used in all Bar Hammer pistols and pepperboxes that Ethan Allen subsequently puts on the market. On January 15th, 1844, a reissue of the patent was granted with an improvement of the main spring and the tumbler. On August 3rd of the same year, a second reissue appears, without any improvements but with a more detailed description of the mechanism.
Patent 3998
The patent describes an improvement of the 461 patent mechanism using only the mainspring to operate the hammer, the dog, and the trigger, simplifying the lock mechanism significantly by eliminating two springs.
The patent also outlines a new improved method for revolving the barrel cluster, using a pitman and ratchet (a series of angular teeth on the back of the barrel cluster.
Patent 13154
This patent describes the mechanism of the percussion breech rifle using a rotary breech-block carried in a cylindrical housing and operated by a top lever. The block contains a black powder charge chamber (e) that communicates axially and laterally, and a projecting segmental breech (f) that closes the rear of the barrel and covers the stock’s loading groove (F).
To put it simply: by raising the lever, a paper cartridge could be inserted into the breech. Closing the breech aligned the bullet with the barrel and exposed the powder to the nipple.
Patent 15454
This patent describes an improved bullet mold for making Minié balls and similar hollow-based projectiles. The mold uses a movable core and cutter that automatically cuts off the sprue along the ball’s curved surface, leaving a smooth, perfectly pointed bullet. A system of grooved pins and rings keeps the mold aligned and prevents the ball from sticking during release.
The design eliminates the need for secondary trimming or swaging, producing uniform bullets efficiently.
Patent 16367
This patent describes 3 separate inventions.
1: A new way to attach the cylinder to the frame. The frame has a conical rod on which the cylinder (which is also conically drilled) rotates. In the center of the conical rod there is a freely rotating screw that holds the cylinder. The advantage of this construction is that the shaft or central pin of the barrel cluster is eliminated and therefore allows for a reduction in diameter of the barrel cluster. This method of mounting is not interesting for revolvers but was used by Ethan Allen on the 4-shot pepperbox where the barrel cluster is considerably smaller than in all other pepperboxes.
2: A innovative way to use the trigger guard as a loading lever to ram the bullets into the cylinder. The trigger guard is connected to the rammer via a rack-and-pinion construction. This is very solid construction, and the force of the lever is well transferred to the bullet rammer. This system is used on all side-hammer percussion revolvers and on the Army and Navy center-hammer percussion revolvers. We also find a very similar system on the Army and Navy lipfire revolvers, but here the rammer serves to eject the empty shells from the cylinder.
3. A nipple with a gas check valve. To my knowledge not applied on any production model.
Patent 18836
The 5 shot side-hammer belt percussion revolver is clearly recognizable in the drawing. This patent describes the mechanism for rotating and locking the cylinder. When cocking the hammer, the ratchet (Fig. 4) that is attached to the hammer via the rocker arm does not directly push the cylinder, but a plate attached to the back of the frame (Fig. 2 and 3) in a rotating movement. The cylinder is connected to this plate via an elongated protrusion that fits snugly into a notch in the rear of the cylinder. The cylinder locking is done as well with this rotating plate, via a pin (Fig.5) that falls into one of the holes intended for this purpose at the right time.
In itself, the rotating plate that moves the cylinder is not something new in 1857. However, previously it has always been applied to designs where the cylinder can be removed from the frame in a forward motion. In this design of a closed frame revolver, the cylinder must be removed from the frame via a sideways movement. The novelty of this patent is the way to connect the plate to the cylinder whereby the cylinder can be pushed out of the frame in a sideways movement without any problem.
Patent 21400
This patent describes 2 improvements:
1. A revolver always has a small clearance between the cylinder and the barrel. As a result, when fired, gases and dirt are blown on the cylinder and part of the frame. This is especially problematic with black powder percussion revolvers. The gases and dirt end up between the cylinder pin and the cylinder, making it difficult to rotate the cylinder. By shaping the cylinder pin partly square (against the end of the cylinder – see Fig. 4) any accumulation of dirt can be better collected so that it does not hinder the correct rotation of the cylinder. This part of the patent applies to all side-hammer percussion revolvers with the exception of the very first models.
2. The other part of the patent is related to the revolving rifles. When aiming with such riffle, one hand of the shooter is located in front of the cylinder. The hot gasses that escape from the clearance between cylinder and barrel when a shot is fired could end up on the hand of the shooter. The invention tries to prevent this from happening. By giving the frame a specific shape, the gases, fire and, in the worst case, a bullet can be deflected either upwards (D in the drawing) or to the side (E). This part of the patent is therefore only applied to revolving rifles.
Patent 22005
This patent mainly describes the way in which the hammer can be securely attached to the side of the frame by giving the frame a certain shape. This principle is used on all side-hammer cartridge revolvers. This patent also covers the rotating and locking of the cylinder.
Integrated Hammer and Tumbler Support: The hammer and tumbler are supported by a solid stud or pin formed as part of the frame rather than being attached separately. This makes the revolver stronger and more durable, especially when the hammer is placed outside the frame.
Cam-Driven Cylinder Rotation Mechanism: A cam system (comprising parts labeled C, L, M, and N) converts the motion of the hammer into the rotational movement of the cylinder. When the hammer is cocked, the cam pushes a pivoting piece (M) into a cavity (S) on the cylinder, turning it precisely to align the next chamber with the barrel. The mechanism locks the cylinder firmly at the firing position and withdraws only during discharge, improving both safety and accuracy.
Patent 27094
This patent describes an improved machine for making rimfire cartridges cases efficiently and uniformly. The invention automates trimming and forming cap cases, ensuring they are cut to exact length and shaped with a hollow rim in one stroke.
It uses a combination of sliding mandrels, revolving chucks, and automatic cutting tools for precise, synchronized motion.
This design replaces slower spinning methods, producing consistent, ready-to-load rimfire cases in a single mechanical cycle.
Patent 27415
This patent describes a machine for forming locking notches or catches on the cylinders of revolvers and similar firearms.
The invention automates the cutting or pressing of cylinder notches—those small recesses that engage the revolver’s locking bolt for chamber alignment.
It uses a system of arbors, indexing plates, and an inclined support to guide a cutting tool that shapes the beveled notches with precision.
Allen’s design allowed for faster, more uniform production of revolver cylinders, improving accuracy and manufacturing efficiency.
Patent 28951
The rimfire cartridge cases of that era had a tendency to expand when fired. If the base of the case expand, it will press against the recoil plate and as a result, will hinder the turning of the cylinder. This patent describes a remedy for this. The recoil plate is slightly milled, except where the cartridge lines up with the barrel (Fig.3). There is therefore virtually no play between the base of the case and the recoil plate for the cartridge ready to be fired. For the remainder of the cylinder’s circumference however, there is more space between the cylinder and the recoil plate, meaning rotation is not hampered by a case base that might have been slightly expanded.
Patent 30033
The text from this patent describes in lengthly words the entire operation of the dropping block rifle, but what the patent is really about is the case ejector (Fig. 3).
The trigger guard, which serves as a lever to move the block (D), is in this design also used to move the case ejector. The drawing shows that the trigger guard rotates around point b. Thus, when the trigger guard is fully lowered, the end of the trigger guard g comes into contact with the ejector at point y and pushes it in a rearward motion, ejecting the casing.
In the patent description, the second “rear” trigger only serves as a lock for the trigger guard. This type of locking has however never been put in production.
Patent 30109
This patent describes the so-called lipfire cartridge. This is a kind of rimfire cartridge where the rim only covers 1/8 of the case circumference, hence the name lip. At first glance, the lipfire cartridge seems a strange development. The rimfire cartridge was already on the market and is much more practical. The first reason for this development is that Ethan Allen wanted to develop a cheaper cartridge that used only one-eighth of the expensive fulminate since this only needed to be in the lip and not over the entire circumference of the case base as with the rimfire cartridge. The second reason is that Ethan Allen thought he could make a stronger cartridge case. Manufacturing techniques in those days were not very advanced and it was not uncommon for the bottom of a rimfire cartridge to crack or expand when fired. With the lipfire cartridge this risk was significantly reduced, which was a big plus, especially for the bigger calibers.
Patent 31695
This patent describes a machine for manufacturing metallic cartridges, designed to automate the joining of the bullet to its metallic case with precision and speed. The machine uses a system of rotating rollers, cutting knives, and automatic clamps to secure the bullet within the metallic cartridge case. Corrugated rollers compress the copper case into the lead bullet, forming firm contact and rolling creases to hold lubricant. Knives trim excess metal raised during rolling, ensuring smooth and uniform cartridges. The mechanism includes spring-loaded spindles, levers, and inclined planes that automatically clamp, rotate, roll, and eject the finished cartridge.
Allen’s design provided a fully mechanical, repeatable process for cartridge assembly—faster, more accurate, and consistent than manual forming.
Patent 33328
The lipfire Army revolver is clearly recognizable on the patent drawing. This patent describes several locking mechanisms: the cylinder pin (Fig. 4), the trigger guard that also serves as a lever for the case ejector (Fig. 3) and the loading gate for the cylinder (Fig. 2).
The patent claim is mainly oriented towards the cylinder pin locking using a small spring loaded latch. (Fig.4) The latch can easily be pressed, releasing the pin and allowing it to be removed.
The top hinged loading gate opening upwards has only been used on the first version of the 44 Army lipfire revolver. This was soon replaced by a far mor practical and more solid bottom hinged gate as described in patent 35067
Patent 33509
This patent is an interesting improvement in the cylinder locking mechanism. The system is based on a lock activated by the trigger and made it possible to eliminate several moving parts. The lock is a lever (G in the drawing) that is pressed against the cylinder by a spring and therefore falls into the locking notch when the cylinder is turned into position. The other side of the lever is in direct contact with the trigger. When cocking the hammer, the pressure of the trigger on the lever is such that the cylinder can rotate freely. This patent has been applied not only to the rimfire revolvers, but also on all lipfire revolvers and the center-hammer percussion revolvers.
Patent 35067
This patent describes 3 interesting topics.
1. An improvement to make the cylinder rotate more easily. The pawl or hand that pushes to turn the cylinder is now placed almost perpendicular to the rear of the cylinder (m on the drawing). Instead of being directly connected to the rocker arm, the hand is now connected but via a lever (H). This construction was not only used in the revolving riffle, but also in all .36 and .44 lipfire revolvers, as well as in the first type .36 and .44 percussion revolvers.
2. A lever connected to the cylinder pin with a gear construction. (Fig.4 and K,M in Fig.2). By turning the lever, the cylinder pin is moved forward, after which the cylinder can be removed from the frame. This part of the patent is only applied to the revolving rifle.
3. A method to adjust the trigger pressure. A screw has been made in the hammer (s in Fig. 5), which can change the notch size where the trigger falls, thereby adjusting the trigger pressure.
Patent 36760
This patent describes a revolving rear sight for rifles with a disk containing multiple holes arranged at varying heights.
By rotating the numbered disk, the shooter can quickly select the correct elevation for different ranges.
A spring stop locks each setting, ensuring precise and repeatable aim adjustments.
Patent 46617
This patent describes the method of ejecting the spent case when rotating the barrel to the side. The construction is extremely simple but elegant. The drawing speaks for itself.
Patent 47688
This patent introduces a two-part metallic cartridge with a brass body and steel base for strength and reliability.
A flanged base securely holds the primer cap, ensuring consistent ignition and preventing gas leakage.
The grooved inner shell surface grips the wad, stops charge movement, and allows the cartridge to be safely reloaded and reused.
The shell is reloadable, offering consistent performance and long service life compared to standard one-use metallic cartridges.
Patent 48249
This patent describes an improved method for constructing gun barrels combining strength and ornamental appearance. Allen’s process uses alternating layers of iron and steel, welded, rolled, and twisted together to form a patterned composite bar.
He then splits the twisted rod and rewinds it, placing the inner surface outward to create both enhanced strength and decorative grain patterns. This technique yields a durable, visually distinctive “twist” barrel, superior in toughness and finish to conventional smooth-forged barrels.
Patent 49491
This patent describes an improved double-barrel breech-loading firearm designed for strength, simplicity, and efficient cartridge extraction. The invention features a hinged breech-cover (D) that opens sideways, locked by a horizontal lever (E) engaging a notch in the breech-piece and secured by a spring-bolt stop (f). A supporting-piece with a retaining hook (d) firmly connects the barrels to the breech but can be easily detached for cleaning or maintenance. The locking-lever doubles as an opener, giving mechanical leverage to release a tight breech. A spring-loaded cartridge extractor (G) with twin projections removes both shell casings simultaneously when operated by a hand lever.
The design allowed fast, reliable reloading and extraction using metallic cartridges, marking a major improvement in double-barrel sporting guns.
Patent 55596
This patent introduces an improved method for heating and soldering double gun barrels efficiently and uniformly. Allen’s system uses a fire-box with blowpipes and interchangeable nozzles to force the flame directly through the gun barrels, evenly heating them inside for tinning and soldering.
A pair of spring-loaded clamps with set-screws holds the barrels securely while joining.
This process allows faster, cleaner, and more uniform barrel assembly compared to traditional wire-binding and open-flame methods.
Patent 84929
This patent covers major improvements to Allen’s double-barrel breech-loading firearm, enhancing strength, functionality, and versatility. Allen reinforced the joint between barrels and breech using a solid metal extension (E) with a dovetailed connection (L) to the breech-iron (D), ensuring a stronger, more durable frame. A hinged breech-piece (G) locks securely via a lever (N) and sliding bolt (O), aided by a spring and friction-roller for smooth and reliable operation. The trigger-guard doubles as an extractor lever, simultaneously ejecting both cartridge shells when opened. An auxiliary rifled barrel (R) can be inserted into a shotgun barrel, allowing the same gun to fire either shot or bullets.
The design provided a robust, convertible sporting gun combining the functions of both shotgun and rifle in one firearm.