US2561505A - Metal fixture for typewriter desks - Google Patents

Description

July 24, 1951 M. Fox A 2,561,505

METAL FIXTURE FOR TYPEWRITER .DESKS Filed April 27, 195o l s sheets-sheet 1 FIC?! l 2 j/ l'f r J5 u W m,

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METAL FIXTURE FOR TYPEWRITER DEsxs 3 Sheets-Sheet 2 Filed April 27, 1950 M. FCX

METAL FIXTURE FOR TYPEWRITER DESKS July 24, 1951 Filed April 27, 1950 3 Sheets-Sheet 5 FIEL 7 y mm,

2 This invention relates 'Wpc in which one of the pedestals is, provided `with a compartment for housing a typewriter and having means for supporting the typewriter Patented July 24, `1951 UNITED STATES PATENT [OFFICE METAL FIXTURE FOR TYPEWRITER DESKS Martiens', chicago, in assignor te The sang Company, Chicago, Ill.

y Application April Z7, 1950, Serial No. 158,575

3Claims, (C1. 312--27) to pedestal desks or the in such manner that it may be. moved from retracted position. inthe compartment to extended writingfposition, and more particularly it relates toi an improved swinging mechanismforthe typewriter platform and a new .arrangement of counter-balancing springs. Y The primaryobject of the invention is to pro- 1 vide a simple, rugged and dependable mechanism for extending and retracting the typewriter platform of the desk, the mechanism being so arranged that the platform swings in a smooth oontinuous arc from retracted position to writing position, and makes its final motion into writing position in an upward and. rearward direction.

Another object of the invention is to provide a mechanism in which there is` sufficient forward component to theinitial movement of the platform from writing position that the platform may be latched in writing position by engagement of `a` spring latch bar with an upwardly open Llshaped notch.

- .Still another object is to provide a mechanism :in which the counter-balancing spring is stretched --and in a dead center position when the platform is retracted so that after a slight forward 11u11 on the platform the spring assists the forward swing thereof substantially all the way to writing position.

, The invention is illustrated in a preferred embodiment in the accompanyingl drawings, in which: Fig. lis a side elevation koi a typewriter desk with the typewriter platform in writing position';` Fig. 2 is a plan view thereof with the desk ytop removed, the platform being in retracted position, and being shown in interrupted lines in writing position; Fig. 3 is a fragmentary plan view similar to Fig. 2, but on an enlarged scale; Fig. 4 is a section taken as indicated on the line 4 4 of Fig. 2; Fig. 5 is a fragmentary sectional View of the latch and latch-trip mechanism; Fig. 6 is a, fragmentary broken front elevational view of the latch and latch-trip mechanism; Fig. 7 is a sectional view similar to Fig. 4, but showing the mechanism with the typewriter platform in a position between retracted and writing positions; Fig. 8 is a sectional view similar to Fig. '7 with the platform in writing position; and Fig. 9 is an enlarged fragmentary sectional view taken as individing legs, which are joined by panel members II surmounted by a top I2. A typewriter oompartment I3 has a bottom wall I4 and a door member indicated'at I5.

` .A pair of tracks I5 have mounting brackets I1 at their forward ends which are screwed to two of the front upright frame members I0 of the desk, and the rear ends of the tracks are fastened to two rear upright frame members with screws IB;

`A carriage I9 is provided with a front pair of anti-friction rollers 20, and a rear pair of rollers 2l, engaged on opposite sides of the tracks I6. Front bell cranks 22 are pivoted to the carriage at 23, and rear bell cranks 24 are pivoted to th carriage at 25.

. A pair of brackets 26, to which is bolted a typewriter piatform 2, are pivotally connected to the ends of the bell cranks 22 and 24 at 8V for parallel movement; and a pair of parallel side links 23 are pivctally connected to the other ends of the bell cranks at 3l).

A pair of guide links 3| are pivotally connected to the side links 29 at 32, and are also pivotally comiected` at 33 to a pair oi' upstanding lugs 34 at the front end of the tracks I6. In assembling the mechanism within the typewriter compart- .ment of a desk, it is necessary that the guide links y corrugated, annular spring grippers 32uv which frictionally grip the Shanks of the studs.

Anl arched cross bar 35 spans the carriage I3 above the rear bell cranks 24, and is fastenedA to the carriage at 33. A transverse .bar 31 extends between the rear bell cranks 24 below the pivots v2-3 and in a position such that tension counterbalancing springs 38 which are fastened to the arched cross bar 35 and to the cross bar 31 are in a dead center position lwhen the carriage is in its most retracted position-that is, the line of the springs 38 passes substantially .directly through the line of the pivots 25 in said position. Due to this dead center arrangement of the counter-balancing springs 38, the springs are in their most elongated condition when the mechanism is fully retracted, and only a slight forward movement of the platform is required to put the counter-balancing springs 38 into operation to assist in the forward and upward movement of the typewriter platform` 21.

As best seen in Fig, 5 a pair of latch assembly plates 39 are fastened inside the upper front about the pivots of the bell cranks.

corners of the typewriter compartment by means of screws 40. A pair of swinging latch arms 4I are pivoted on the latch plates 39 at 42 and are drawn downwardly against stop pins 43 by tension springs 44 which are fastened to the swinging arms 4I and to spring lugs 44a. A latch bar 45 extends transversely between the swinging arms 4|. When the typewriter platform 21 is elevated ltoward the writing position shown in Fig. 8,the latch bar 45 strikes cam surfaces 52 at the rear of the platform brackets 26, pivoting the latch arms 4l against the tension of spring 44, and in writing position the latch bar engages a pair of upwardly open notches 46 adjacent the cam surfaces 52 to retain the platform in writingI position. Mounted at the rear of the typewriter platform 21 is a bifurcated bracket 41 in which a latch-trip 46 is pivoted on a rivet 49. The forward portion of thelatch-trip 48 is a finger piece 50, and the rear portion 5l thereof projects wbeneath the latch bar 45 when the platform is in writing position. Thus, in order to disengage the latch bar l5 from the upwardly open notches 46 of the platform brackets it'is merely necessary to depress the finger piece 53 of the latch-trip 48 so as to elevate the swinging latch arms 4I against the tension of the spring 43.

y The operation of the device will be readily understood. When it is desired to withdraw the `typewriter from the compartment I3, the door'A l5 is opened, the forward end of the typewriter platform 21 is grasped and the platform is pulled forward. The motion of the platform 21 and carriage I9 causes the guide link 3l to rotate about its pivot 33, thus pivoting the bell cranks 22 and` 24 about their pivots 23 and 25, and beginning the elevation of the platform 21 in a smooth arc As soon as the counter-balancing springs. 38 are off their dead center position, the rotation of the bell* cranks and elevation of the platform 21 is assisted by the tension of the counter-balancing g'springs, which continue to exert a lifting force throughout substantially the entire travel of the platform 21-enough so that the momentum of the platform is almost sufficient to complete the travel to writing position shown innig; 8 without further effort on the part of the operator. As the platform reaches writing position, the latch `bar 45 comes into action as previously described to latch the platform 21 in writing position. The

initial travel of the platform from writing position has suiiicient forward component that the frictional engagement between the latch bar and the rear upright surface of thenotch 46 is adequate to maintain the platform in writing position. Y

The operation of the latch-trip has been prein the art.

lviously described. The mechanism is extremely I claim:` y. l Y

l. A metal fixture for a typewriter desk in which a platform carrying a typewriter may be extended from a compartment and swung up to writingposition, said fixture comprising: tracks for attachment to the walls of the compartment; a carriage antifrictionally journalled on said tracks and provided at each side with a front bell crank and a rear bell crank; brackets for a typewriter platform pivotally mounted on one end of each of said bell cranks for parallel movement; side links connecting the other ends of the bell cranks; a pair of guide links connecting said side links to positions near the front ends ofsaid tracks; `and a latch mechanism for releasably securing the platform brackets in writing position.

2. A metal fixture as specified in claim l wherein the platform brackets have. upwardly open notches, the latch member is a transverse bar mounted on a pair of swinging arms and is spring urged downwardly into engagement with the open notches, and a latch-trip adapted to be supported by the platform brackets in such a position as to have a portion projecting beneath said transverse bar in writing position, said latchtrip being pivotable to elevate the transverse bar and free it from said notches.

3. A metal fixture as specified in claim 1 in which the platform brackets have upwardly open notches and the latch mechanism comprisesfa pair of latch plates adapted to bemounted on the walls of the typewriter compartment, a pair of swinging arms on said latch plates, a transverse bar mountedl on said arms to engage said upwardly open notches, and spring means urging said bar downwardly into engagement withthe notches. MARTIN FOX.

' file of this patent:

UNITED STATES PATENTS I Name ADate"- Number Fox June 10, 1341

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