William A. Box Iron Works Co.

**Names** | Dillon Box Iron Works Company (1902-1923?)
 **Products** | Electric travelling cranes

Mining machinery
Railway crossing signals

The **William A. Box Iron Works Company**, formerly the **Dillon Box Iron Works Company**, was a Denver, CO-based metalwork company founded in 1902 by William A. Box and Frank Dillon, which manufactured electric traveling cranes, mining machinery and railway crossing alarms. They are most notable for their Denver sirens, which are known for their rarity and unique design.

## History

In 1902, the Dillon Box Iron Works Company was formed in Denver, CO, headed by William A. Box and Frank Dillon. It was found at the time that the numerous steam whistles and fire bells used at the time were confusing, and sought to create a siren that would be noticeably distinct. The company experimented with creating electric sirens in 1905, most of which would prove to be a failure. In 1910, Frank Dillon would leave the company and the company would be renamed to the William Box Iron Works. Box would find success with the Denver Type-A, and by 1914 had introduced other Denver-branded sirens such as the Duplex and Quadruplex. These would be patented in 1915.

The rotors on the sirens were directional (similar to ACA's sirens), and were the first electric sirens to have true directional rotors, louder when running counterclockwise. Metal arrows were bolted to the front stator to assist with correct installation. Some of the sirens used single cast stators, while others use two piece stators bolted together. Despite being bare, they were incredibly well-built and durable, with many units surviving over 100 years in the elements despite lacking any shielding for the rotors and stators. Despite the company being renamed, all Denver sirens were tagged with the original Dillon Box Iron Works name. The sirens would be marketed by Hendrie & Bolthoff Mfg. Co, as well as the Silver Engineering Company.

William A. Box Iron Works would continue to produce the Denver sirens, as well as a wide variety of other products, until 1931, when its founder, William A. Box, unfortunately passed away. Today, the Denver sirens are surprisingly widespread considering most units are well over 100 years old. Some found use as fire sirens, and still remain next to their fire stations. Most are still hooked up to power, although unused. Many sit inside custom built shelters to protect them from the elements, as their rotors are completely exposed and unprotected otherwise. Notable locations include Lebanon, TN, Jerome, AZ (nearby to a Cosgrave siren), and Friendsville, TN. The vast majority of surviving Denver sirens are Duplex and Quadruplex models, with roughly 24 of each unit surviving today, with even fewer being active. Three Denver Type-As remain in existence, while only a single inactive Type-B survives.

## Products

### Stationary Electric Sirens

#### Duplex

The **Duplex** was the main single headed siren sold by Dillon Box, introduced in 1914, and were single headed sirens with a pair of 20-port single tone rotors and stators attached together, suspended between two supports that held bearings to keep the rotors in place. These were driven by a single sided 3HP AC motor running at 1750RPM, available in either single or three phase AC. Early models used 20 long vanes on each rotor, though sometime after 1916, this was changed to 5 long vanes and 15 short vanes. A large, rounded motor cover protects the motor from the elements, and everything is attached to a long frame. These would be produced until William Box's death in 1931. These were less common than the larger Quadruplex, and few of these survive today, some still hooked up to power but unused.

    A special coded Duplex was also offered for a short period, equipped with a large electromagnetic drum brake, which brought the siren to a quick halt, not dissimilar from a Sterling Code Siren. None are known to still exist. A variant also existed which was designed for use on motorships.

#### Quadruplex

    The **Quadruplex** is a dual headed version of the Duplex that was introduced in 1914, and were the most popular siren that was sold by Dillon Box Iron Works. These are essentially a Duplex with an additional pair of rotors and stators in front of the other two, which would theoretically increase sound output. Due to the added weight of the extra rotors, an additional support and bearing are located at the front of the siren, with the siren's overall length being significantly longer. The Quadruplex uses 4 20-port rotors and stators, driven by a single sided 3HP or 5HP AC motor running at 1750RPM, and was available in either single or three-phase AC. The 5HP model was recommended by Dillon Box for sirens which would run multiple consecutive cycles, which would put more wear on the motor. Early models used 20 long vanes on each rotor, though sometime after 1916, this was changed to 5 long vanes and 15 short vanes. A large motor cover helps protect the motor from the elements, and everything is attached to a long rectangular frame. The Quadruplex is tied with the Duplex as the most common Denver siren surviving today, with several being left in place due to the difficulty of removing such a large siren. These would be produced until William Box's death in 1931. Many were used as fire sirens before being retired, though some are still hooked up to power and used as a backup. Others are used as noon whistles.

#### Type-A

The **Type-A** was Denver's earliest successful attempt at creating a large electric single headed siren first created around 1910, and were somewhat unique compared to the other two models. This siren has the distinction of being one of, if not the earliest successful large-scale electric siren ever produced. The siren uses a pair of 12-port rotors and stators attached together, which were both driven by a single sided 1.5 or 2HP AC motor running at 1750RPM, which was only available in single-phase AC. Unlike the other siren models, this siren used a gearbox containing a gear reduction drive to connect the motor and the rotor together, with the motor being located parallel to the gearbox. This was due to the lack of acceptable electric motors that could reach an effective RPM at the time. The siren's rotors are suspended between two supports which have bearings on top, which keep the rotor in place. Due to the additional components included, the siren's rectangular motor cover is significantly larger than other Denver sirens. The siren was deemed to be maintenance intensive and did not perform very well, which led to it being redesigned in 1914. The gear reduction drive was removed, and the motor was coupled directly to the rotor, just like the Type-B. None of these transmission drive sirens exist today.

The 1914 redesign saw the reduction drive being removed, and the motor was directly coupled up to the rotor to simplify the design. This made the siren more compact and less mechanically complex, which helped remedy the issues operators had with the transmission drive units. Early Type-A units used staggered rotor and stator ports, though by 1920 this was changed to being non-staggered with a simpler rotor design. This design would be used all the way until the Type-A was discontinued.

Two Denver Type-A units are known to survive today, one being an earlier staggered rotor unit in Canova, SD, while the other is a later simplified unit located in Kanorado, KS.

#### Type-B

The **Type-B** was an improved version of the Type-A, with several design changes to improve its performance. The siren is driven by a single 2HP AC motor at 1740RPM, and the siren is equipped with a single (or optionally, a double sided) 20-port single tone rotor and stator. The extra bearings and supports that the Duplex uses are not included, and the rotor is directly coupled to the motor instead. The siren is much more compact than a Duplex, which makes it more useful where larger sirens are impractical.

The Type-B was optionally available with a 150VDC motor, which was designed for use on motorships which lacked the ability to use steam whistles. The motorship *Kennecott* was one such motorship which was known to be equipped with one of these sirens. The Type-B has only a single surviving example, a dual rotor version located in Ferriday, LA.

#### Center Drive Duplex

    The **Center Drive Duplex** was a small dual rotor siren that were produced beginning in 1925, and were significantly more compact than most of Denver's sirens. These were 6-port single tone sirens, using two 6-port rotors driven by a single dual sided 5HP motor in between, running at 3000RPM. These sirens were intended to compete with the very popular Sterling Model M and Federal Electric Type Mach. B which were outselling the Denvers by a large margin. The siren's rotors have three long vanes, which would produce a significant undertone. The siren was available with a protective cover attached to the bottom mount, which would protect the siren from rain and debris. The siren would only be produced for 6 years. as William Box died in 1931 which led to all sirens being discontinued. Only one of these sirens has ever been documented, on the old fire station in Wheat Ridge, CO. The fire station was demolished long ago, with the siren disappearing along with it, and they are now extinct.

### Boxco siren

The **Boxco siren** is a small vertical electric siren that was created by William Box in the early 1910s. The Boxco was sold separately from the other Denver sirens under the "Boxco" brand, and is a small 12-port siren driven by a small electric AC motor. These sirens could be ordered as either electric or hand-cranked sirens, for use as a small mine whistle, shift changing whistle, or as a vehicular siren. The siren is very simple, with the 12-port rotor and stator above the motor, with a stand attached to the bare motor which allows the siren to be mounted. The siren has no housing, like most Denver sirens. The siren could also be ordered as the Suspended Siren. Few of these Boxco sirens still exist.

### Boxco Suspended Siren

    The **Suspended Siren** is a small single rotor siren which was uniquely designed to hang from a ceiling or wall fixture. These are a variant of the "Boxco" electric/hand cranked siren that was created by William Box. These sirens were equipped with an eyebolt attached to the motor which allowed it to be hung from a hook, or suspended on a wire. The siren uses a single 6-port rotor and stator which is located below the motor. These sirens were likely designed for use in industrial areas or mines, where a small, easy to install and replace siren was desirable. Little else is known about this siren, and it is likely extinct.

### Sterling Duplex and Quadruplex

In 1917, the Interstate Machine Company, which would later become the Sterling Siren Fire Alarm Company, sold their own variants of Denver's sirens presumably under licence from William Box Iron Works. These came with their own Duplex and Quadruplex models, but were much smaller than the Denver Sirens. They were available exclusively in 20/20-port (or 20/20/20/20-port for the Quadruplex) single tone, and dual headed models could have coding mechanisms on the stators. Like the Dillon Box designs, the Duplex and Quadruplex used a dual sided rotor/stator coupled to one or both sides of the motor, with the motor being placed on a raised stand resembling those used on the Model M. A small rounded motor cover protects the motor, while a sounder is placed on top of each stator to direct the sound downwards. The siren as a whole is attached to a single long frame, making this unsuitable for pole mounting, but perfect for roof mounting. Unlike the Model M, the Duplex and Quadruplex have the chopper coupled to the motor through a clutch, rather than directly coupling the rotor to the motor.

These would be discontinued in the early 1920's in favour of the much better Model M that predated it, and competed with it. These are now extremely rare, as all surviving units are over 100 years old and none are known to be currently active or operational. The Quadruplex in particular is technically extinct, as any original Quadruplexes that have survived to present day have since been converted to Duplexes. The last known fully-intact unit has also since been destroyed, leaving only a handful of Duplexes in existence.