US3016614A

US3016614A - Drafting machine of the guide-wire type

Info

Publication number: US3016614A
Application number: US691093A
Authority: US
Inventors: David G Falconer
Original assignee: JONKER FRIEND CORP
Current assignee: JONKER FRIEND CORP; JONKER-FRIEND Corp
Priority date: 1957-10-18
Filing date: 1957-10-18
Publication date: 1962-01-16
Anticipated expiration: 1979-01-16

Description

Jan. 16, 1962 D. G. FALCONER 3,016,614

DRAFTING MACHINE OF THE GUIDE-WIRE TYPE Filed on. 18, 1957 2 Sheets-Sheet 1 7 Dawn 6. l LcozvEe INVENTOR.

1962 D. G. FALCONER 3,016,614

DRAFTING MACHINE OF THE GUIDE-WIRE TYPE Filed Oct. 18, 1957 2 Sheets-Sheet 2 66 w 56 F2? 'DlqU/D 6. 62 V 68 h BY WW? I j 7' States David G. Falconer, Washington, D.C., assignor to .lonlren Friend Corporation, a corporation of Delaware Filed Get. 18, 1957, Ser. No. 691,093 1 Claim. (Cl. 33--8tl) This invention has for its aim the provision of an improved form of drafting machine, for use in connection with the usual form of flat or inclined drafting table, to enable the full range of drawing or design operations to be accomplished efficiently and without disadvantages encountered in the use of previously known machines of this type.

In particular, the invention permits the employment of a straight main or reference support element which will support the actual pencil or pen guiding straight-edge or protractor element, hereinafter called the drafting instrument, in such a Way that the latter can easily be maintained in a set position, or equally well be moved to a different position, strictly parallel to itself, in any desired direction over the table surface. The main or reference support is itself in the form of a shaft, whose opposite ends are guided by taut wires in such a way that the support is maintained accurately parallel to one edge of the table or board regardless of how it may be moved parallel to itself to place the other parts in desired locations. The invention also provides related features which permit the parts to be moved as desired without smudging or touching the work being done, without hindrance from small articles lying on the working surface, and under continuous control of the operator.

The invention further provides, for use with a reference support of the kind described, an improved form of connection whereby the protractor or straight-edge drafting instrument will be guided by the reference support to the desired working position, but so arranged that the protractor or drafting device or instrument can easily be slightly tilted up from the Working plane (-to clear the work), or even lifted entirely free from the main support shaft for immediate replacement by a difierent type of drafting instrument. This feature is obtained without any sacrifice of the accurate geometric relation of the parts in use. The same arrangement provides a convenient support for one hand or the forearm of the draftsman, and by which the drafting instrument such as a straight-edge guide or protractor can be tilted away from the work, moved as desired from place to place, or held firmly in the working position. Other advantages of the invention will become apparent from the following description.

Reference is now made to the accompanying drawings forming a part of this disclosure, and in which:

FIGURE 1 is a perspective view of the essential parts of one preferred embodiment of the invention.

FIGURE 2 is a fragmentary sectional view taken along linen 2-2 of FIGURE 1.

FIGURE 3 is a similar sectional view taken on line 3--3 of FIG. 1.

FIGURE 4 is a partial plan view of the essential features of a modified form of the invention.

FIGURE 5 is a sectional view taken on line 5-5 of FIGURE 4.

FIGURE 6 is a diagrammatic illustration of a modified way of winding the guide wires for the main support shaft.

FIGURE 7 is a view similar to FIG. 1 of a slightly modified form of the invention, and illustrating a form of parallel ruler for use with any of the various forms.

FIGURE 8 is a sectional view taken on line 3--8 of FIGURE 7.

diff

Referring first to FIGURES 1 to 3 of the drawings, the invention is illustrated as applied to the usual board, table top or like drafting surface designated reference numeral 10. Rolling along two opposite marginal edges of the board 10 are cylindrical hubs 12, 14 which are fast on the opposite ends of the main reference element shown as shaft I6 of cylindrical form. Upper and

lower guide wires

18, 20 of flexible but substantially inextensible cord or wire, are secured at their opposite ends to the board corners as at screws 22.. Each wire is wrapped at least once about the periphery of the corresponding hub, which may thus roll along the wire surface with the wire in turn lying upon the board surface. Adequate friction between wire and hub is ensured by the

tensioning springs

24, 26, but tensioning weights may obviously be submitted if desired.

Since the shaft 16 is of smaller diameter than the hubs, the shaft is kept out of contact with the board and in fact can clear small objects lying on the working surface. The arrangement described requires no overhanging parts, so that the board or table may be placed directly against walls or others furniture Without interference. If desired, each hub may be provided with a flange, as at 28, engaging the side margin of the board 10, to minimize end play if such is objectionable for the work in hand.

The pencil-guiding drafting instrument or protractor is indicated as a whole by reference numeral 30, and may take any desired form. However, its manner of connection to the shaft support 16 is desirably such as to ensure its positional rigidity without hindering its movement when desired, or complete removal if that is wanted. Thus, the connection preferably takes the form of a bracket 32 which rests upon the shaft 16 with a wedging action due to its own weight or the hand or forearm of the operator upon the upper surface of the bracket. As best shown in FIGURE 3, the actual bearing surface between the bracket and shaft may be provided by protuberances 34 on the inclined sides of the former, which slide along the shaft, and these may incorporate inherent friction sufficient to minimize accidental shifts, as when the board is tilted. FIGURE 3 indicates in dash lines the way in which such a bracket can be tilted by the operator, as merely by a sliding force exerted on the bracket top surface, to clear the work itself and prevent any smudging. Obviously, also, the entire unit of bracket and protractor can be lifted free when desired. The cantilever arrangement relative to shaft 16 permits the desired tilting action of the drafting instrument.

For use when long lines are to be drawn parallel to a long edge of the board or table, a collar 36 may be positioned on the shaft 16 and locked in place as by a setscrew 38 preferably forcing a nylon or like clamp element against the shaft 16. The collar size will of course be less than the diameter of the hubs 12, 14 so that the collar will clear the working surface.

In the simplified form shown in FIGURES 4 and 5 of the drawings, the hubs are omitted, and the wires make several turns about the mere ends of shaft 16. In this case, of course, less clearance will be provided for articles lying on the working surface of the board. It is to be understood that the same drafting appliances as described above may be used with the form shown in FIGURES 4 and 5. To avoid the necessity for excessive frictional contact tension, the wires may be anchored to the shaft ends in the manner indicated in FIGURE 5, by a clamp screw 40 engaging a central part of the wire 18, which makes several turns about the shaft 16 before extending to the table edges. It is important that in this form, as well as in all the other forms of the invention, only rolling contact elements lie between the shaft and the work surface; no rubbing contact is involved.

A differentformof windingarrangement for the

wires

18 and 20 is shown in FIGURE 6, in which each wire is actually formed in two independent pieces designated 42 and: 46. Each piece is separately anchoredto the shaft 1 6. as by having1its end secured in a hole in the shaft, and the wires are then wrapped in opposite senses about the' shaft so that the distance 48 will remain constant as the shaft rolls along thetable.

ln the embodiments described above, the guide wires lie on the table or board, or at least within its outer periphery. It is also possible to arrange the wires entirely outside the periphery, as by the form shown in FIGURE 7. Here, edge brackets .56 have the wire ends anchored to them, so that the wires are outside the boards edge and preferably slightly below its top surface. It will be seen that this involves a hub diameter greater than as described above, and to avoid any sliding, slippage or the like due-to the difference in peripheral speed as between the hub and the shaft, sleeves 52 and 54 loosely receiving the shaft 16 are arranged to roll along the board surface in the desired manner and regardless of the'diameters of the hubs.

FIGURE 7 also illustrates a particularly advantageous embodiment of the arrangement carried by shaft is. Here, a simple stirrup element 56 is hooked over the shaft 16,v and between the shaft-engaging half loops 53 and 6d the shaft carries the bracket of a straight-edge or protractor unit 62. The fiducial edge of the stirrup element is indicated at 64 in FIG. 8, and the elements e and 62 can be swung about the shaft as indicated, to clear the work surface. An abutment so on the protractor is preferably arranged to engage a strip 68 on the stirrup element 56 when the protractor is tilted, so that the straight edge part 64 of the stirrup is automatically raised clear at the same time. The stirrup half loops lie inside sleeves 52 and 54- and straight edge 64 is thus nearly as long as the table width, to permit short or long parallel vertical lines to be drawn accurately.

Having described several preferred forms of the ini vention, it is to be understood that the principles of the invention can be effectuated by other specific arrangements, and that all such are included in the scope of this invention as fall Within the true spirit and meaning of the appended claim. In the claim, reference to the shaft itself is to be taken as including any parts, such as hubs, which are or may be functionally integral therewith so as to turn with the shaft, unless the contextindicates that such an interpretation is not intended.

What is claimed is:

In a drafting machine or the like, in combination, a support shaft mountedfor free movement always parallel to itself along and above a working surface, a bracket having inclined side Walls encompassing the shaft and having bearing elements disposed to contact the shaft whereby to locate the bracket for sliding motion lengthwise of the shaft, a drafting instrument carried by saidbracket and extending outwardly along and above said surface to one side only of said shaft, to permit tilting motion of the bracket about the shaft as an axis andthereby to lift the drafting instrument away from the working surface; a straight-edge element having stirrup portions partly encirclingsaid shaft for tiltingmovements of said straight-edge elemennand cooperating abutments on said drafting instrument bracket and said straightedge element, to tilt the latter element upon tilting movements of the bracket.

References Cited in the file of thispatent UNITED STATES PATENTS