US2557735A

US2557735A - Metal fixture for typewriter desks

Info

Publication number: US2557735A
Application number: US670411A
Authority: US
Inventors: Fox Martin
Original assignee: Seng Co
Current assignee: Seng Co
Priority date: 1946-05-17
Filing date: 1946-05-17
Publication date: 1951-06-19
Anticipated expiration: 1968-06-19

Description

June 19, 1951 M. Fox

METAL FIXTURE FOR TYPEWRITER DESKS 3 Sheets-Sheet 1 Filed May 17, 194e NUN '.Nm NNW N A .QA NN l L i- N\\ N\ N\ l: NN

rl- \\m/ f\\| NNN NN N KNNV 3 Sheets-Sheet 2 M. FOX

METAL FIXTURE FOR TYPEWRITER DESKS Filed May 17, 1945 June 19, 1951 June 19, 1951 M ,.#OX 2,557,735

n METAL FIXTURE FOR '1.YPEWRITER DESKS I Filed May 17, 1946 3 Sheets-Sheet 3 Patented June 19, 1951 UNITED sTATss A T f NT QFFI-CE 2,557,735 METAL FIXTURE FOR TYPEWRITER DESKS Martin Fox, Chicago, Ill., assigner to The Seng Company, a corporation of Illinois Application May 17, 1946, Serial No. 670,411

Y 8 Claims. (Cl. 312-28) This invention relates to pedestal desks of the type in which one of the pedestals is provided with a compartment for housing a typewriter and having means for supporting the typewriter in such manner that it may be moved from retracted position in the compartment to extended writing position, and more particularly to an improved locking device for the platform in writing position, and a new arrangement of counter-balancing springs.

The primary object of the invention is to provide a rigid, secure mounting for the typewriter when the platform is in writing position that does not rely on the springs to hold it in locked position, and will not become unlocked accidentally.

Another object of the invention is an improved mounting for counterbalancing springs which will equalize the force utilized in moving the platform from one position to another. Although counterbalancing springs have been commonly used in typewriter desks, the force has not been heretofore properly equalized, with the result that the swinging movement of the platform is uneven and there has been a tendency of the platform either to jerk out of the operators hand, or to slam into its terminal position.

The present invention is an improvement of the structure shown in my Patent 2,245,526, issued June 10, 1941.

The invention is illustrated in a preferred embodiment in the accompanying drawings, in Which- Figure 1 is a plan View of a desk with the top removed and showing the typewriter platform in retracted position within the compartment of the desk, taken as indicated at line I-I of Fig. 2; Fig. 2 is a vertical sectional view, taken as indicated at line 2 2 of Fig. 1; and Fig. 3 is a fragmentary view similar to Fig. 2, but showing the typewriter platform locked in writing position.

In the embodiment illustrated, a conventional pedestal desk has corner posts 4 which are joined by panel members 5, which are surmounted by a top 6. A typewriter compartment 1 has a bottom wall 8 and a door` member indicated by dotted lines at 9.

A pair of side plates I are secured to the upper front side walls 5 by means of screws I I. The plates are provided near their upper ends with inwardly extending studs or pins I2. The side plates I0 also serve as front supports for tracks I3, whose rear end portions are supported by screws I4.

y -A carriage I5 is provided with a front pail:

of antifriction rollers I5, and a rear pair of rollers |1 which engage opposite sides of the tracks |3. A front pair of bell cranks I8 are pivoted to the carriage at I9, and a rear pair of bell cranks 2|! are pivoted to the carriage at 2|. The short arms of the bell cranks are connected together for parallel movement by links 22 making pivotal connections at 23 and 24.

An arched cross bar 25 extends above the rear bell cranks and is xed to the carriage I5, as indicated at 2li. A pair of tension springs 21 extend from the cross bar 25 to studs 28, on the bell cranks 2t, which are disposed above and slightly in rear of the pivots 2| when the platform is in writing position, as viewed in Fig. 3. Another pair of tension springs 29 extend from the cross bar 25 to studs 3D, on the bell cranks 2|), which are disposed above and in advance of the pivots 2|, when the platform is in writing position. It will be noted that in its motion from retracted position to writing position the bell crank 2D rotates through an angle of approximately 180, and that the studs 28 and 3|) for the tension springs are separated by an angle of about about the pivot 2|. Thus, during the first part of the travel from writing position to retracted position, the tension in springs 21 is increased only slightly, while the tension in springs 29 is increased considerably. Conversely, during the last part of the travel to retracted position, the tension in springs 21 is increased considerably while the tension in springs 29 is increased only slightly. At each end of the motion, one of the two springs is being contracted rather than stretched. This arrangement of the counterbalancing springs provides a very smooth and easy movement for the platform with a minimum of effort on the part of the operator.

A typewriter platform 3| is carried by a pair of metal `brackets 32 which have inwardly extending flanges 33 to which the platform is gripped by upright bolts 3d. The platform is provided with a cross member 33a which serves as a stop. It will be noted that the platform may be secured either above or below the flanges 33, depending upon whether the operator prefers a high or low platform position.

The brackets are provided with rear upwardly extending arms 35 equipped with rearwardly open notches to engage over the rear pair of pins I2 on the side plates ID. The brackets also have front upwardly extending arms 36 with rearwardly presented notches which are slightly undercut, so as to form hooks 31. When the hooks 31 are in engagement with the front studs I2,

it will be noted that it is necessary to raise the front end of the platform 3| before the platform can be unlocked and drawn forwardly. The brackets 32 are pivotally connected to the rear bell cranks at 38, and the front ends of the brackets make a pivotal pin-and-slot lost-motion connection with the bell cranks I8, as shown at 39 in Fig. 3. It will be noted that this lost-motion connection permits a slight upward tilting of the platform, to disengage the hooks 35 from the front pins l2.

The bell cranks I8 are also provided with studs 4B which are adapted to be engaged by latching members 4I, which are pivoted to the carriage at 42 and urged upwardly =by springs lla. The latching members have upwardly extending fingers 43, which are adapted to slip into notches A4 at the front end of the tracks I3 and release engagement with the studs 40, so that the carriage will be locked in its forward position L and the platform will become unlocked. This will permit the platform to be swung up on the bell cranks into writing position.

The operation will be readily understood. When it is desired to withdraw the typewriter, the door 9 is opened and the platform is pulled forwardly on the carriage as far as it will go. The latch M will then lock the carriage and release the platform so that with the help of the counterbalancing springs the platform may be swung up easily into the locked writing position shown in Fig. 3. To return the typewriter, the front end of the platform is raised slightly and then swung forwardly and downwardly until engaged by latches 4I, and then rolled back into the compartment.

The foregoing detailed description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, for some modifications will be obvious to those skilled in the art.

I claim:

1. In combination with an office desk having a compartment for housing a typewriter and platform; horizontal rails at opposite sides of the compartment; a carriage slidable on said rails; a pair of front bell cranks pivoted to said carriage; a pair of rear bell cranks pivoted to the carriage and linked to the front bell cranks for parallel movement; an arched cross bar over A said rear bell cranks and secured to said carriage; a platform pivotally connected to each of the bell cranks; a tensioned spring extending from said cross bar to a part of one arm of a rear bell crank which is in front of its pivot with the carriage when the platform is in its upper writing position and is in rear of said pivot when the platform is in its lower retracted position; a second tensioned spring extending from the cross bar to a part of the other arm of said rear bell crank which is in rear of its pivot with said carriage when the platform is in its upper writing position and is in front of said pivot when the platform is in its lower retracted position; and means for releasably holding said platform in its upper writing position.

2. Apparatus as specified in claim 1, in which holding means comprises a set of spaced apart pins within the compartment at each side thereof, and a set of rearwardly open notches at each side of the rear portion of the platform adapted to engage the pins when said platform is in writing position, one opposed pair of notches being undercut slightly to form hook-shaped openings to receive the pins, and one opposed pair of bell cranks making lost-motion pivotal connections with the platform to permit latching engagement with the pins.

3. Apparatus as specified in claim l, in which the platform is pivotally secured to the bell cranks by means of a pair of metal brackets having a. pair of rearwardly presented notches and a pair of rearwardly open hooks to engage spaced apart pins within the compartment, to connection between said brackets and one pair of said bell cranks being by a pin and slot, and said brackets having inwardly extending horizontal flanges to 'which the platform is bolted.

4. Metal fixtures for typewriter desks in which a platform carrying a typewriter may be extended from a compartment and swung up to writing position, said fixtures comprising: plates for attachment to the inner walls of the compartment; front and rear pairs of bell cranks; and brackets for the platform pivotally secured to one pair of said bell cranks and making a lost motion pivotal connection with the other pair of bell cranks, said plates and brackets being adapted to make pin and open notch connections with each other at one end of the brackets and pin and open hook connections with each other at the opposite end.

5. Metal 'fixtures for typewriter desks in which a platform carrying a typewriter may be extended from a compartment and swung up to writing position, said xtures comprising: plates for attachment to the inner walls of the compartment; tracks for attachment to the walls of the compartment; a carriage antifrictionally journalled on said tracks and provided with pivotally mounted front and rear pairs of bell cranks; and a pair of platform brackets pivotally secured to one pair of bell cranks and making a lost motion pivotal connection with the other pair of bell cranks, said brackets and plates making detachable pin and open notch connections with each other at one end and pin and open hook connections at the opposite end.

6. Metal xtures as specified in claim 5, in which the traveling carriage has a fixed arched cross bar, and a plurality of counterbalancing springs are tensioned between said cross bar and points on the rear pair of bell cranks so as to equalize the application force used in moving the platform from one position to another.

'7. In combination with an oflice desk having a compartment for housing a typewriter and platform; horizontal rails at opposite sides of the compartment; a carriage slidable on said rails; a pair of front bell cranks pivoted to said carriage; a pair of rear bell cranks pivoted to the carriage and linked to the front bell cranks for parallel movement; an arched crossbar over said rear bell cranks and secured to said carriage; a platform pivotally connected to each of the bell cranks; a counterbalancing spring connected to said crossbar and adapted to counterbalance the weight of the platform and typewriter; a pair of spaced pins within the compartment at each side thereof; and a set of rearwardly open notches at each side of the rear portions of the platform adapted to engage the pins when said platform is in writing position; one opposed pair of notches being undercut slightly to form hook-shaped openings to receive the pins, and one opposed pair of said bell cranks making lost motion pivotal connections with the platform to permit latching engagement with the pins.

8. Metal fixtures for typewriter desks in which a platform carrying a typewriter may be extended from a .compartment and swung up to Writing pOSitiOn, Said fixtures comprising: a car- 5 6 riage adapted to be mounted for travel in said siton, said points being separated by an angle compartment; front and rear pairs of bell cranks of about 90 about the pivot. pivotally secured to said carriage; brackets for the MARTIN FOX. platform pivotally secured to said bell cranks; means for releasably holding said platform in REFERENCES CITED Writing position; an arched crossbar Substan' The following references are of record in the tially directly above the pivots of one pair of the me of this patent: bell cranks and secured to the carriage; a pair of tension springs extending from said crossbar UNITED STATES PATENTS to spaced points on one of said bell cranks which 5 9 Number Name Date are above and substantially equidistant from the 2,245,526 Fox June 10, 1941 pivot thereof when the platform is in lwriting po-