Cyrus Grant Spalding (1835-1918), a book keeper and inventor from Boston, Massachusetts, was a holder of two US patents for simple adding machines: patent №146407 from 13 January 1874, and №293809 from 19 February 1884. The second patent of Spalding (see the lower patent drawing) is for a device (an improved version of the first patented device), which had an additional wheel for hundreds, while the first device has a special index for hundreds.
The Spalding Adding Machine (based on both patents) is nested in a beautiful wooden case with dimensions: 8″ x 8″ x 2″, while the device itself has dimensions: 7″ x 7″ x 1″. The calculator has a clock hand for units, co-operating with a dial graduated from to 99, showing the figures 5, 10, 15, etc., to 95, for every five graduations. Another similar hand or arrow and dial to register the hundreds is also provided to the right, having a capacity to register nineteen hundred. Attached to the arrows, through a shaft connection at the back of the casing are ratchet wheels, having respectively the same number of teeth as the graduation of the dial to which each hand belongs.
Cooperating with the hundred-tooth ratchet of the units and tens register hand is a ratchet and lever motion device to turn the arrow from one to nine points of the graduation of the dial. The ratchet and lever-motion device consists of the spring-pressed pawl E, mounted on the lever arm D, engaging the hundred-tooth ratchet, the link or push-rod F, the lever G, and its spring O. A downward action of the lever G, will, through the rod F, cause a like downward action of the lever D, causing the ratchet pawl E to be drawn over the ratchet teeth. Upon the release of the lever G, the spring O, will return it to its normal position and through the named connecting parts, ratchet forward the arrow.
The normal position of the pawl E is jammed into the tooth of the ratchet and against the bracket C, that forms the pivot support for the pivot shaft of the arrow. This jammed or locked combination serves to stop the momentum of the ratchet wheel at the end of the ratcheting action, and holds the wheel and its arrow normally locked until the lever G is again depressed.
The means for gauging the depression and additive degrees of action of the lever G is produced through the slides or keys marked a, having finger-pieces c, springs f, and pins e, bearing against the top of the lever G, combined with what may be called a compensating lever marked K.
The specification of the patent states that the depression of a key will depress the lever G and the free end will engage the bent end t, of the compensating lever K, and rock its involute curved arm M, upward until it engages the pin e of the key, which will block further motion of the parts.
The carry of the hundreds is accomplished by means of one-step ratchet device represented by the parts lever R, pawl T, spring P, and operating pin g. When the hundred-tooth ratchet nears the end of its revolution, the pin g, made fast therein, engages the free end of the ratchet lever R, and depresses it; and as the hand attached to the hundred-tooth ratchet wheel passes from 99 to the 0.
The operation of the adding machine of Spalding, which will add columns of figures with unerring accuracy and surprising rapidity, can be seen in the lower instruction of the machine.
It seems several hundred Spalding adding machines (a.k.a. Surprise Adder) were produced and sold by the end of 19th century, but only about ten devices known to exist now.
Biography of Cyrus Spalding
Cyrus Grant Spalding was born on 26 September 1835, in Waltham, Massachusetts, a son of Cyrus Spalding (1802-1880), a blacksmith, and Susan Straw Grant (1807-1895), a school teacher. Cyrus Spalding the father was born on 28 Sep 1802, in Hillsboro, New Hampshire, and died 22 May 1880, in Chicopee Falls, Hampden Co., MA. He married Susan Straw Grant (6 Sep 1807-23 Feb 1895) from Lyman, Maine, on 29 Sep 1831, in Hillsborough.
Cyrus Spalding Jr. married to Emily Clark Swart (born 25 Mar 1838 in Pittsfield, Massachusetts–died 3 Aug 1912), daughter of the blacksmith David Swart (1814-1891) and Mehitable C. Clark (1815-1880), on 15 December 1859, in Chicopee, Hampden county, Massachusetts. On 6 October 1860, was born their first daughter, Susan Emily (died in July 1937), and in 1867 a second daughter, Mary A., who died as a child.
In the middle 1860s Cyrus Spalding took part in the Civil War (he was enlisted in 10th Unattached Company of Massachusetts Volunteer Militia), then returned in Chicopee, where by 1870 he worked as a book keeper. Cyrus then moved for several years to Boston, then returned to Springfield, MA, and its surroundings (Northampton and Chicopee), working again as a book keeper, while trying to establish the production and selling of his adding machine.
Cyrus Spalding died in 1918 and was buried in Maple Grove Cemetery, Chicopee, Hampden County, Massachusetts.