US248723A - School-desk - Google Patents

Description

(ModeL) E. G. DURANT.

SCHOOL DESK.

UNrreo Srares PATENT Orrrce.

EDWVARD G. DURANT, OF RAOINE, \VISGONSIN, ASSIGNOE OF ONE-HALF TO THOMAS KANE, OF CHICAGO, ILLINOIS.

SCHOOL-DESK.

SPECIFICATION forming part of Letters Patent No. 248,723, dated October 25, 1881.

Application filed December 9,1880. (Model) To all whom it may concern:

Be it known that I, EDWARD G. DURANT, of Racine, in the county of Racine and State of Wisconsin, have invented certain Improvements in School-Desk of which the following is a specification.

This invention relates to that class of desks having hinged falling tops in which the top is automatically sustained by locking devices upon being raised to its operative position and then automatically released upon being raised slightly above said position, so that it may he turned down.

Many devices and combinations of devices operatingas above have been devised and used.

The object of the present invention is to produce a device which shall be cheaper, stronger, and more certain in its action than those now in general use; and to this end it consists in the combination of a standard having a shoulder, an arm pivoted to the standard, and pro vided with notches or shoulders, and a lockingpawl pivoted to the arm and arranged to receive both a pivotal and a sliding motion, as hereinafter explained. arrangement of the pawl so that by an endwise movement upon its pivot it is caused to lock rigidly to and unlock from the carryingarm or other support is a leading feature of my invention, and the parts are susceptible of modification in form and arrangement without substantially changing their construction or mode of operation.

The drawingsillustrate my device in its most approved form.

Figure l is a side elevation of the upper part of a desk-standard and the hinged arm provided with my locking device, the arm being shown in its operative position and the side or face of the standard broken away to expose its inside face to view. Fig.2 is a similar view, showing the arm raised above the operative position to lock the pawl out of action. Fig. 3 is a similar view, showing the arm in the course of its descent with the pawl held out of action. Fig. 4 is a similar view with the arm near the end of its descent at the instant that the pawl is beingdisengaged from the devices which keep it out of action. Fig. 5 is a perspective view, showing the construction of the The construction andarm and pawl that they may interlock to keep the pawl out of action. Fig. 6 is an inside face view of the standard and arm, showing the lid-supporting arm from the opposite or inner side of the desk.

A represents the rigid standard of the desk; B. the top-supporting arm, pivoted to the standard in such manner as to swing vertically, and O the supporting or locking pawl, pivoted at one end to the arm B and resting at the-other end in a recess in the standard. The recess in the face of the standard to receive the free end ofthe pawl has three distinctive featuresviz., the inside shoulder, a, the outside shoulder, 0, and the inclined top 0.

The pawl is connected to the swinging arm B by means of the pivot-pin d, which is passed vthrough an elongated opening or slot, 0, in the pawl, so that the pawl may receive a longitudinal sliding motion thereon in addition to its swinging motion.

On the pivoted end of the pawl there is a stud or tooth,f, and in the arm B there is a recess or notch, 9, into which the stud may be engaged by sliding the pawl with the free end forward. When the stud is thus seated in the recess the pawl is prevented from swinging on its pivot, and is caused to swing with the arm B.

The parts being constructed as above operate as follows: When the arm B is raised to its operative position the pawl, being free to turn on the pivot, is drawn backward until its free end falls behind and against the shoulder a, as shown in Fig. 1, so as to sustain the arm. At this time the pivot-pin stands in the forward end of the slot 6. Upon raising the arm B above the operative position (shown in Fig.

1) the pawl is drawn backward until its rear end is elevated and its forward end sustained upon the shoulder Z), whereupon it slides downward and forward upon its pivot until the stud fengages in the notch g, so as to lock the pawl and the arm rigidly together, as represented in Fig. 2. If, now, thearm belowered, the pawl,

by reason of its rigid connection thereto, will 5 be carried therewith, and will have its forward end carried upward over shoulder a without engaging thereon, as plainly shown in Fig. 3. As the arm completes its downward movement the forward end ofthe pawl encounters the top of the recess at 0, whereby the pawl is pushed backward upon its pivot and its lip or stud fdisengaged from the arm, as shown in Fig. 3, whereupon the pawl falls by gravity to the position indicated by the dotted lines in Fig. 4, ready to assume the position shown in Fig. 1, when the arm is again raised.

The unlocking of the pawl, as in Fig. 2, may he secured by gravity, or by so forming the shoulder I) and the under side of the pawl that they will engage, as shown in Fig.2, and thus render the action of the parts positive.

The form of thelocking-lip on the pawl may be changed, and there may be two lips, as indicated in dotted lines, or more. The only essential requirement in this regard is that the arm and the pawl shall interlock firmly at the proper time. p

The skilled mechanic will perceive that many changes may be made in the form and arrangement of the details without changing the principle of action.

As seen in the drawings, the arm is cut away in the upper side near the pivot at s, in order that itmay swing upward past the edge of the stationary part of the top, which is commonly known as the "ink-well strip, without cutting the strip away; but this feature is not claimed as any part of the present invention, the right being reserved to make it the subject of a future patent.

I am aware that in automatic desks of the class to which my invention relates it is old to make use of a lid-arm provided with a sustainingpawl and with a spring to sustain said pawl in an unlocked position. the pawl being released from engagement with the spring by coming in contact with the desk-standard. Such arrangement I do not claim, my present invention being restricted to a combination wherein a sustainingpawl interlocks directly and rigidly with the lid-arm, thus avoiding the necessity of a spring and the many difficulties which follow its use.

Having thus described my invention, what I claim is 1. The combination, in a desk, of a standard, a ertically-swinging lidsupporting arm, and an intermediate supImrting-paWl having a pivotal and a sliding connection to one of said members, the pawl and said member being provided with surfaces, substantially such as described, which interlock as the pawl is moved endwisc to secure the two parts rigidly and firmly together, substantially as described.

2. A standard provided with the shoulders to and c, in combination with the arm B, hinged thereto, and the sliding and swinging pawl O, constructed and operating substantially as described.

3. The combination of the arm prox'idcd with the recess or shoulder, the slotted pawl having lip F, and the connectingpivot, substantially as set forth.

4. The combination of the standard having a shoulder, I), the hinged arm B, and the armsustail'ling pawl 0, having a pivotal and sliding connection with the arm, and constructed to interlock rigidlytherewith in the manner and at the times substantially as described.

5. The combination of the standard having the shoulders a b c, the pivoted arm B, having shoulder or recess, and the slotted pawl having the lip, substantially as set forth.

6. The combination of a standard, a vertically-swinging arm pivoted thereto, and an automatic pawl having a sliding and pivotal connection to one of said members, and constructed, substantially as described and shown, to interlock rigidly with said member when acted upon by the other member.

EDWARD G. DURANT.

Witnesses:

JOHN A. MltoMAnAN, JOHN F. BIGKEL.

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