In 1904, the construction firm of Page & Shnable (or, in some sources, Schnable) had a contract to excavate lock foundations on the Hennepin Canal near Colona, IL. The project involved removal of 8 feet of muck from overlying bedrock, a task for which existing machinery was inadequate.
To solve the problem, John W. Page, a partner in the firm, designed a new kind of excavating bucket. Rigged to a combination stiffleg and guy derrick, it operated like a wheeled scraper, with the hitch immediately above or behind the cutting edge, and the dumping hitch enabled it to be discharged without unhooking it from the cables. Page eventually began manufacturing the buckets.
At some point over the next fifteen years, his partner designed and patented his own version of a dragline bucket. It consisted of a pivoting shell inside a fixed frame, and it dumped out its back end. This was done by releasing the tension of the drag line, causing the back of the shell to drop away from the back gate of the frame while pivoting at the front of the frame. After dumping, the shell returned to its horizontal digging position, with the back gate blocking the open back end of the shell.
Advantages touted for the Shnable design included superior performance in very large rock and in sticky material; dumping clear of cables and linkage; the capability to work up- or down-hill; smoother cuts; the ability to dig closer to the machine, dump closer to the end of the boom and at a greater radius than a conventional bucket; and, ease of repair. In 1919, the buckets were rated from 1 to 3.5 cubic yards, with weights from 2,850 to 9,600 pounds. Despite its merits, the Shnable bucket was eventually discontinued, and Page’s bucket is still the industry standard for excavation by dragline.
The slackline dragline also evolved in the early 1900s. Digging in the same manner as the Page and Shnable buckets, the slackline bucket functions more like a scraper. It is bottomless and is used in applications that do not require the load to be lifted from the ground, such as dragging aggregates to a feeder.
The Historical Construction Equipment Assn. (HCEA) is a 501(c)3 non-profit organization dedicated to preserving the history of the construction, dredging and surface mining equipment industries. With over 4,000 members in 25 countries, activities include publication of a quarterly educational magazine, Equipment Echoes; operation of the National Construction Equipment Museum and archives in Bowling Green, OH; and hosting an annual working exhibition of restored construction equipment. Individual memberships are $30.00 within the USA and Canada, and $40.00 US elsewhere. HCEA seeks to develop relationships in the equipment manufacturing industry, and we offer a college scholarship for engineering students. Information is available at www.hcea.net, by calling 419-352-5616 or e-mailing [email protected].
