US 553860 A
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Description (OCR text may contain errors)
UNITED STATES PATENT OFFICE.
GEORGE lV. LONGSTAFF, OF BRIDGEPORT, CONNECTICUT.
SPECIFICATION forming part of Letters Patent No. 553,860, dated February 4, 1896.
Application led October 2, 1895.
Serial No. 564,429. (No model.)
To all whom t may concern.'
Bo it known that I, GEORGE W. LoNGsrAFF, a citizen of the United States, residing at Bridgeport, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Cabinet- Tables; and I do hereby declare the following t0 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.
My invention relates to cabinets such as are suitable for type-writers, sewing-machines, rbc., but more particularly has reference to that class of cabinets in which the table or platform supporting the sewing-machine or type-writer may be so tilted, lowered, or manipulated as to cause the sewing-ma chine or type-writer to disappear.
The object of my present improvement is to provide a very simple device of this character in which little or no effort is required to effect the proper working thereof.
In the accompanying drawings, which form a part of this application, Figure 1 is a sectional elevation of a cabinet constructed in accordance with my improvement; Fig. 2, a sectional elevation taken in a plane at right angles to the section shown at Fig. 1, and Fig. 3 a detail perspective showing the spring which I employ as an equipoise.
I Similar numbers of reference denote like parts in the several figures of the drawings.
1 is any ordinary cabinet-frame, and 2 is a platform tting closely within an opening in the table of the frame and capable of being projected up through this opening or depressed out from the same in the manner common to devices of this description.
3 are guideways secured to the frame immediately below the platform, and 4 is a slideblock within said ways.
5 is a bracket, by means of which the platform 2 is secured to the block 4, so that when said block is reciprocated within the guideways it will carry the platform with it.
G is a box, preferably of metal, which is secured to the frame at any suitable location at a point near the bottom of the guideways, and j ournaled within this box is a short shaft 7.
S is a volute spring within this box, one end of which spring is secured to the shaft 7,
while the other end is secured to the box itself, as clearly shown at Fig. 3.
9 is a ratchet-disk, which is rigid with the shaft 7 outside of the box, and 10 is a cranklever loose around this shaft and having pivoted thereto a pawl11 capable of engaging with said ratchet, whereby the lever and shaft may be secured together as to rotation, for the purpose presently explained.
12 is a crank-pin extending from the extremity of the lever 10, and 13 is a linkwhose extremities are pivoted, respectively, to said crank-pin and to a bracket 14, which latter is secured to the platform 2.
The type-writer or sewing-machine-or other device is mounted directly upon the platform 2 in the usual manner. The proper tension of the spring 8 being first determined by turning the shaft 7 in any ordinary manner, as by a wrench, this tension is preserved by locking the pawl 11 with the ratchet 9.
In operating my improved cabinet a slight pressure is simply brought to bear upon the top of the platform, which will depress the latter down to any suitable plane, as shown in dotted lines at Fig. 1, the block 4 sliding in the guideways 3 to permit of this, while the tension of the spring increases by the act of lowering the lever 10, so that such spring serves as an equipoise to the platform and the parts carried thereby.
The adjustment of the spring is of course made such that it will not act to elevate the platform as soon as down pressure thereon has been released, although if desired the tension of the spring may be so adjusted as to do this.
Any weakening of the spring caused by constant use may be readily compensated for by simply turning the shaft 7 so that the pawl will take into a new notch.
In restoring the parts of my improvement to a condition for use the operator simply grasps the arm of the sewing-machine or other device supported on the platform and by a very slight effort raises the same up to its elevated position, the spring of course :materially assisting in this operation.
While I do not deem it necessary to provide any special device for locking the platform in elevated position, still such device may of course be used, and I have therefore IOO be seen in Fig. l, the crank-arm and link extend more nearly in straight line when the platform is in elevated position and the leverage against the lifting-power of the spring is reduced. The spring and its inclosing box occupy but little space under one end of the platform, and the bracket-arm 5, extending from block l to the farther end of ,the table, makes a very rigid support for said table.
The pivoting of the link 13 to the bracket li is of course equivalent to the pivoting of such link directly to the platform itself, While the pivoting of the other end of this link to the pin 12 is equivalent to a pivoting directly to the lever itsel and I therefore do not wish to be limited to the precise construction shown and described with reference to the manner of pivoting this link.
Having thus described myinvention, what I claim as new, and desire to secure by Letters Patent, is
The cabinet-frame having a guideway, and the platform connected to a slide-piece moving in said guideway,the crank-arm conn eeted by a link to said slide-piece, the box fixed near the bottom of the guidewayhaving bearin gs in which a shaft is carried, and a coiled spring connected to the box and shaft with a tendency to rotate the latter, said shaft having ratchet-and-pawl connection to the crank above mentioned, all being combined substantiall y as described.
ln testimony whereof I affix my signature in presence of two witnesses.
GEORGE XV. LONGS'IAFF. itnesses:
F. XV. SMITH, Jr., M. T. LoxGDEN.