Adjustable support for school furniture
US 540531 A
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v (No Model.)
A ANDREN ADJUSTABLE SUPPORT FOR SCHOOL FURNITURE. N0. 540,531.
Patented June 4, 1895.
i===nllllllllllll "UN-men STATES PATENT 'rr cni. I
ALBAN ANDREN, OF BEVERLY, ASSIGNOR TO THE CHANDLER ADJUSTABLE CHAIR AN-D DESK COMPANY, OF BOSTON, MASSACHUSETTS.
ADJUSTABLE SUPPORT FOR SCHOOL FURNITURE.
SPECIFICATION forming part of Letters Patent No. 540,531, dated June 4, 1895.
Application filed February 11,1895. Serial No. 537,887. (No model.)
To an whom itmay concern:
1% it known that I, ALBAN ANDRFN, a citizen of the United States, and a resident of Beverly, in the county of Essex and State of 5 Massachusetts, have invented new and useful Improvements in Adjustable Supports for School Furniture, of which the following, taken in connection with the accompanying drawings, is-a specification.
This invention relates to improvements in adjustable supports for furniture such as desks, chairs, seats, 650., and it is particularly well adapted for school furniture which requires adjustment'from time to time relative r 5 to the height or size of the scholar for which the chair, seat or desk, &c., is to be used. Ad-
j ustable supports for this purpose are principally of two kinds, namely, those depending on interlocking pawls, teeth or corrugations, 2c and those in which the parts are held together by frictional contact.
My invention relates to the latter kind. In frictional holding and adjusting devices for thispurpose it is of the greatest importance 2 5 that the friction holding device should be so perfect and positiveas to prevent the parts from moving relative to each other after being adjusted and clamped together and for this purpose I construct my invention as follows, reference being had to the accompanying drawings, wherein-'- Figure 1 represents a side elevation of my improved adj ustable device, shown as applied to a chairor seat. Fig. 2 represents a rear 3 view. Fig. 3 represents a central vertical section. Fig. 4: represents a cross-section on the line 4 4:, shown in Fig. 3; and Figs. 5 and 6 represent modifications of such cross-section.
Similar letters refer to similar parts wher- 0 ever they occur on the different parts of the drawings.
A represents the flange of the upwardly projecting base portion A which is preferably made of semi-circular or curved section as shown in Fig. 4, or it may be made of a V shaped or l l shaped section or flat or equivalent cross sections as shown respectively in Figs. 5 and 6 without departing from the essence of my invention. The interior portion or surface aof the upright base portion A is wedge shaped or inclined as shown in Fig. 3.
B is the vertically adjustable shank secured at its upper end to the furniture 0 in any suitable manner, which shank has a crosssection corresponding to the interiorshape of the upright base portion A as shown in the drawings. I
The shank B has a wedge shaped or inclined front surfaceB' adapted to fit against the inclined or wedge shaped interior surface a. of the upright base portion A as shown. The rear portion B of the seat or furniture shank B is also made inclined or wedge shaped, and against it is fitted a clamping wedge or inclined bar D the lower end d of which is preferably pivoted or made to rest .in, a cavity a in the base portion as shown in Fig. 3.
b is a vertical slot in the seat or furniture shank B as shown.
E is a headed screw threaded fastening bolt passing through a notch or perforation in the upright base portion A and through the slot 1) in the seat or furniture shankB, as well as through a perforation in the clamping wedge D and provided with a nut e or other suitable fastening device as shown.
The clamping wedge D has an inclined surface d adapted to fit against the inclined or Wedge shaped rear portion B of the furni 8o ture shank B as shown.
From the above it will be seen that four inclined or wedge shaped frictional surfaces are employed in my improved device, namely, the interior wedge shaped or inclined surface a of the upright base portion A, the front inclined or wedge shaped surface B of the shank B, the rear inclined or wedge shaped surface 13 of said shank, and the interior inclined or wedge shaped surface (1 of the 0 clamping wedge D as fully shown in Fig. 3.
It will thus be seen that I do not depend on simply two inclined faces to secure the 'furni ture shank to the base portion, but depend on twice the number, or four, inclined or 5 wedge shaped surfaces to effect the result of positively securing the furniture shank to the upright of the base portion by which I am enabled to secure the parts together without danger of sagging when a downward pressure ion is brought to bear on the seat or other furniture. In this manner I obtain a most strong and positive frictional holding device which is capable of a most nice vertical adjustment to any desired height without the need of cogs, grooved bars, pawls or other interlocking devices.
Having thus fully described the nature, construction, and operation of my invention, I wish to secure by Letters Patent and clai1n 1. An adjustable support forschool or other furniture consisting of a base portion having an interior inclined or wedge shaped surface, a vertically slotted and vertically adjustable furniture shank having on one side an inclined or wedge shaped surface adapted to fit the said interior inclined surface of the base portion and provided on its opposite side with a similar inclined or wedge shaped surface, a movable outer wedge or clamping bar having an inclined or wedge shaped surface adapted to fit against the adjacent inclined surface of the shank opposite the point where said shank bears against the base, and a screw bolt passed through said wedge and base and through the vertical slot of the intermediate furniture shank and provided on one end with a head and on the other end with a nut, substantially as and for the purpose set forth.
2. An ad justable support for school orother furniture, consisting of a base portion having an interior inclined or wedge shaped surface, a vertically adjustable furniture shank provided with a vertically elongated slot, the opposite sides of said shank being formed with inclined or wedge shaped surfaces one of which is adapted tofit against the said interior inclined surface of the base portion, a movable outer wedge or clamping bar having its lower end pivotally supported on one side of the base portion and the inner surface of said wedge or bar being inclined or Wedge shaped to fit against the adjacent inclined surface of the furniture shank, and a headed screw bolt passed through said movable wedge and through the base portion and the vertical slot of the furniture shank and provided with a nut, substantially as shown and described.
In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, on this 6th day of February, A. I). 1895.
VVINTHROI L. MALooN, IIOL'IEN B. PERKINS.