US 236320 A
Description (OCR text may contain errors)
NITED STATES PATENT O FICE.
FREDERICK B. GINN, OF OAKLAND, CALIFORNIA.
'ARITHM ETICAL FRAM E.
SPECIFICATION forming part of Letters Patent No. 236,320, dated January 4, 1881.
Application filed October 5, 1880. (No model.)
To all whom it may concern:
Be it known that I, FREDERICK B. GINN, a citizen of the United States, resident at Oakland, in the county of Alameda and State of California, have invented certain new and useful Im provements in Arithmeti-cal Frames; and 1 do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to'make and use the same, reference being had to the accompanying drawing, and to letters or figures of reference marked thereon, which form a part of this specification.
This invention relates to arith metical frames for school, class, and private practice; and it consists in the improved features of construction and combination hereinafter fully described, and particularly pointed out in the claim.
The drawing represents a plan view of the device partly broken away.
Referring by letter to the accompanying drawing, A designates the frame of the machine, having a closed back, open front, and grooves B B at the sides, between the mat O and the back D, for the reception of the ends of the sliding slips E. The length of the sliding slips E is less than the width of the frame A at the grooves BB, in order that the slips may be moved tothe right and left in the grooves. The slips E are in this instance provided each with nine figures, and eighteen of the strips are placed in the frame. This size is intended for private use, and is made of wood or paper. For school use the frame is made larger and the figures on the slips of such size that they may be seen from any part of the room.
When the strips are all pushed to the lefthand side of the frame the nine columns of eighteen figures each are in their normal position. By sliding any one of the strips to the right the combination will be changed; and it is obvious that when each slip is moved the combination will be changed, so that a great variety of combinations are given for practice in adding, and no time is lost in effecting the changes.
The advantages of the machine are plain. The device is quite simple, is inexpensive, and is of great benefit in aiding individuals as well as classes to become proficient in adding.
It is obvious that any number of sliding slips with any number of figures upon each may be used without departing from the spirit of my invention.
I am aware that an arithmetical frame provided with slats having numbers or figures on their opposite faces and arranged to be revolved or turned over in a frame to change the combinations in the columns is not new, as the same may be seen in Patent No. 43,545, July 12, 1864., and no claim to said construction is made-herein.
Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent of the United States, is-- As an improvement in arithmetical frames, the frame A, having the closed back, open front, and grooves B B at the sides, between the mat O and back D, in combination with the series of figured or numbered sliding strips E, constructed and operating substantially as and for the purposes set forth. 4
In testimony whereof I affix my signature in presence of two witnesses.
FREDERICK B. GINN.
ANDREW RYDER, M. P. KAY.