US2520021A - Drafting instrument - Google Patents

Description

g- 22, 1950 L. VEYRET ET AL 2,520,021

DRAFTING INSTRUMENT Filed Feb. 26, 1948 S2 in INVENTORS Lou/5 l/fVRL-T PAUL VflA/ET Patented Aug. 22, 1950 DRAFTING INSTRUMENT Louis Veyret, Neuilly-sur-Seine, and Paul Vanet, Le Vesinet, France, assignors to La Cellophane, Paris, France, a French company Application February 26, 1948, Serial No. 11,244 In France May 15, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires May 15, 1963 This invention relates to drafting instruments.

The drawing boards used in drafting rooms are commonly equipped with a system of pulleys andsteel wire guide lines, serving for the displacement of a flat rail or straight edge on the board in such a manner as to remain constantly parallel to itself. This rail is attached to the steel wires by a clamping arrangement for looking it to the same after making the desired adjustments.

The present invention contemplates an improvement applicable to drawing boards of this type. This improvement consists essentially in fitting the table with a simple device permitting removal or replacement of the rail by a very brief operation without disturbing the original adjustment. Such a procedure is requi ed when it is desired to work freely on the same board, either with the aforesaid rail or with a drafting machine comprising a system of jointed parallelograms travelling over the entire surface of the board, or for other purposes.

A form of practicing the invention is represented in the accompanying drawings in which:

Fig. 1 is a longitudinal vertical section of the device taken on the line |l' of Fig.

Fig. 2 is a top plan view thereof;

Figs 3 is a transverse vertical section taken on the line 33 of Fig. 1;

Figs. 4 to 9 are detail views illustrating different embodiments of the invention;

Fig. 10 is an end elevation of the form of Fig. 9; and

Fig. 11 is a diagrammatic view of a drawing board showing the invention applied thereto.

The drawings, particularly Figs. 1 and 2, show only the righthand side, with respect to the draftsman, of the board I bearing the flat rail or straight edge 2 whose end is to be attached to the lateral guide wire 3.

This connection is made, according to the invention, by means of a bracket 4 whose upper portion carries a threaded pin 5 entering a slot 6 in the rail, and permitting this bracket to be locked to the rail by means of the tapped knob I. At its lower portion, the bracket 4 is fashioned in the form of a fork with a gap 8, utilized for attachment to the wire, between its parallel faces. For this purpose a turned clamp 9, (Fig. 3) is shown as having an axial hole to receive the wire 3. The clamp 9 may be looked upon the wire by means of the screw ID. The clamp 9 has a shoulder upon which the bracket 4 can be fitted at the gap 8, without play, or with only very slight play sufiicient to avoid binding.

6 Claims. (CI. 33-80) An exactly similar arrangement is placed at the other end of the rail 2, on the lefthand side of the drawing board, permitting the necessary adjustments in accordance with the angle at which it is desired to set the rail.

It is obvious that under these conditions the rail, when manipulated with the hand, may be displaced over the surface of the board as though immovably attached to the wires 3, and that it may nevertheless be removed from the wires. instantly, and completely removed from the board, by simply lifting it. To make this operation completely convenient, the under side of the board or its supporting structure may be provided with two crutches, or small brackets, to receive the rail at this time. The inverse operation of replacing the rail is accomplished with equal rapidity and without any difficulty.

While the method just described for engaging the bracket 4 on clamp 9 is simple and convenient, nevertheless numerous variants are possible, some of which have been shown in Figs. 4 to 10 of the drawing.

Figs. 4, 5 and 6 show that the gap 8 provided in bracket 4 may have different shapes on the lateral external surface of this piece, and that any of these could alternatively be placed in the internal surface a. In these forms, the rail is very effectively held in place if a slight deformation of the wire is utilize-d to produce a transverse force tending to impel the clamp 9 toward the interior of the gap 8. However, when it is desired to remove or replace the rail, it becomes necessary to engage or disengage clamp 9 manually in the gap.

According to Fig. 7, bracket 4 takes the form of a simple metal strip suitably bent, to which may be attached a flexible spring H for better retention of clamp 9.

Fig. 8 is a further embodiment comprising a spring i2 whose flexibility is such as to permit direct engagement or disengagement of rail 2 without any additional operation, the said rail being furthermore exactly centered and free from play because of the conical form of the shoulders provided on clamp 9, provided the width of the spring is slightly greater than the length of the cylindrical portion at the waist of the clamp 9.

Figs. 9 and 10 show an arrangement representing an inversion of the foregoing. In this embodiment, the bracket 4 shown separately in Fig. 9 carries a pin I3 provided with a neck engaged by a spring M which is so shaped as to prevent disengagement of the pin in the direction perpendicular to the plane of the drawing. This All these embodiments, which are mentioned, by way of example, and others which will be 3-D",

parent to a person skilled in the art, are within the scope of the invention which is to be restricted only in accordance with the following claims.

What is claimed is: 1. In a drawing board having a system of pulleys and guide wires to permit a fiat rail to be displaced over the board in such a manner as to remain constantly parallel to itself, an adjustable attaching means comprising a tubular member slidable on said wire and adjustable clamping means securing the same in fixed. position'on said wire, a groove formedin said member, a'bracket carried by said rail at each end, said bracket having a depending arm formed with a slot opening downwardly to engage said-groove for releasably securing said rail to said wire, whereby the rail may=be separated from said wires by lifting and may be replaced without change in its original adjustment 2. An attaching means, as set forth in claim 1, in which the adjustable clamping means for said tubular member comprises a screw carried by said member and engaging said wire.

1 3. An attaching means, asset forth in-claim 1, inwhioh said bracketsare adjustably mounted for longitudinal movement along said rail.

4. An attaching means, as set forth in claim 1, in which said rail is provided with a longitudinal slot at each end thereof and said brackets are adjustably secured by means passing through said slot.

5. In a drawing board having a system of pulleys and guide wires to permit a fiat rail to be displaced over the board in such a manner as to remain constantly parallel to itself, an adjustable attaching, means .comprising a tubular member Mslidable on, said wire and adjustable clamping means securing the same in fixed position on said wire, a groove formed in said member, a bracket carried by said rail at each end, said bracket having depending portions spaced to form a downwardly openingchannel therebetween, said depending portions being adapted to engage said groove for releasably securing said rail to said wire whereby the rail may be separated from said wires by lifting and may be replaced without change in its original adjustment.

6. Jim-attaching means asset forth in claim 5, in which said depending portionsare resilient for securing the samein position-in said groove.

LOUIS PAUL=VANET.

-l. REFERENCES CITED The following references are of record in the file, of this, patent:

' UNITED STATES PATENTS Number Name r Date 3 607,814, ,Aigner, July 26,1898 1,812,477 Green, June-3,0, 1931

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