US2051115A - Drafting machine - Google Patents

Drafting machine Download PDF

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US2051115A
US2051115A US705725A US70572534A US2051115A US 2051115 A US2051115 A US 2051115A US 705725 A US705725 A US 705725A US 70572534 A US70572534 A US 70572534A US 2051115 A US2051115 A US 2051115A
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Prior art keywords
arm
pulley
board
plate
shaft
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Expired - Lifetime
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US705725A
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Vard B Wallace
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Vard B Wallace
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B43WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43LARTICLES FOR WRITING OR DRAWING UPON; WRITING OR DRAWING AIDS; ACCESSORIES FOR WRITING OR DRAWING
    • B43L13/00Drawing instruments, or writing or drawing appliances or accessories not otherwise provided for
    • B43L13/02Draughting machines or drawing devices for keeping parallelism
    • B43L13/04Guides for rulers
    • B43L13/06Guides for rulers with pivoted guide rods

Description

Aug. 18, 1936. v. B. WALLACE 2,051,115
DRAFTING MACHINE Filed Jan. 8, 1954 2 Sheets-Sheet 1 .lllornfys Aug. 18, 1936.
v. B. WALLACE DRAFTING MACHINE Filed Jan. 8, 1934 l IH 2 Sheet-Sheet 2 Allllllll Patented ug. i8, 1936 DRAFTING MANE Vard B. Wallace, Alhambra, Calif.
Application .ianuary 8, 1931i, Serial No. 705,725
2 Claims. (Cl. Sii-'wl My invention relates to drafting machines and. has particular reference to machines for supporting scales or straight edges upon a drawing board so that the same may be moved to various posi- 5 tions upon the board without changing the alignment of the scales or straight edges with predetermined base lines upon the board.
In the art of mechanical drafting, it is common practice to employ a drawing board upon which the paper of which the drawing is to .be
made is secured and to proceed with the construction of the drawing by determining a. base line on the drawing relative to which other lines are extended in parallel or at right angles thereto.
In making such drawings, particularly drawings of considerable size, it is difficult to maintain correct parallelism by the use of an ordinary T- square and drafting machines of the type employing a jointed arm secured to the board and carrying scales or straight edges have been employed with the arm to insure maintenance of the straight edges parallel to the predetermined base line independent of the movement of the arm to place the straight edges over various portions of the drawing board.
An object of my invention is to provide a drafting machine of this character, in which the scales or straight edges may be supported upon a'single arm having a joint therein, and in which a flexible endless belt is employed to maintain the scales in alignment with a predetermined base line independent of movement of the arms.
Another object of the invention is to provide a drafting machine of the character set forth in which an endless belt operating over pulleys is employed to maintain alignment of the scales with a predetermined base line independent of the movement of the arm, even though such arm lmay be moved through several complete rotations.
Another object of the invention is to provide an arm construction for a drafting machine, as set forth, in which the arm may be readily adiusted to maintain taut relation with the endless band or bands.
Other objects and advantages of the invention will be apparent from a study of the following specifications, read in connection with the w accompanying drawings, wherein Figure 1 is a plan view of a drafting machine constructed in accordance with' my invention, attached to a drawing board; v
Figures 2 and 2a together are detail sectional views through one of the arm sections shown in Fig. i, the view being taken along line II-H of Fig. l;
Figure 3 is a detail plan view of the protractor and scale mounting employed with my invention;
Figure t is a detail sectional view, taken along 5 line IV-IV of Fig. 3;
Figure 5 is a detail sectional view, taken along line V--V of Figure 3;
Figure 6 is a detail plan view illustrating a lock and latch which may be employed with the l0 protractor constructed in accordance with my invention; and
Figure 'l is a detail sectional view, taken along line Vil-VII of Fig. 3, illustrating the hinged connection for the latch-operating mechanism. i6
R',ferring to the drawings, I have illustrated in F g. 1 a drawing board I to whichV my drafting maci ine, illustrated at 2, maybe secured, as by meant` of a clamp 3. The clamp 3 may be either permanently secured to the board, as by screws, 20 or by suitable screw-clamping means, not shown, such as is commonly employed for the attachment of universal drafting machines to drawing boards of the character herein set forth.
A pair of scales or straight edges t and 5 are 25 illustrated as being carried upon the outer end of a jointed arm, consisting of two sections 6 and 1, a section of the arm 6 being formed with the bifurcated head Ba pivotally secured upon a vertically extending shaft 8 rigidly connected to 30 the clamp 3. The bifurcated head 6a preferably includes two bearing members 6b and 6c, having aligned openings therein for the reception of ball bearings 6d and 6e, respectively, so that the arm 6 may be moved about the shaft 8 with relatively 35 little friction.
The shaft is illustrated as including a reduced section 8a, the end of which is threaded as at 8b to receive a locknut 8c to securely hold the same rigidly to the bracket 3, a suitable lock e0 washer 8d being interposed between the outer surface of the bracket 3 and a shoulder 8e formed upon the shaft 8. The upper portion of the shaft 8 is illustrated as being tapered as at 8f for reception in a tapered hub of a pulley 9, which pulley i5 may be clamped upon the shaft 8 as by means of a locknut 9a, while the extreme upper edge 8g of the shaft 8 forms a bearing surface for engaging the ball bearing 6d.
The major portion of the arm 6 is illustrated 50 as being formed of an elongated tube having a central bore 6j thereby permitting the same to be relatively light, to which the head 6a may be attached as by means of a plug 6g insertable in the bore Bf to extend beyond the outer end of the arm 6 anciA into a bore 6h in the head 6a where it may be attached as by means of a pair of screws 6k and 6m. The screws 6k and 6m are preferably threaded into the same threaded opening En so that by loosening one of the screws and tightening the other, the plug 6g may be aligned accurately in the center of the bore 6h. If desired, a suitable bearing collar 6p may be employed between the outer end of the head 6a and the end of the tubular arm 6.
Th-e inner end of the arm 8 is formed with a jointed head I0, to which is fixed a shaft as by means of pressing the same through a ball bearing I a, and then pressing the ball bearing f into a suitable annular recess |0b formed in the ally mounted upon the shaft so that it is free to turn thereon, the pulley |2 being provided with a pair of grooves |3 and |4 for the reception of a pair of bands I5 and I6. The band I5 is illustrated as extending from the pulley I2 to the pulley 9 and is, preferably, formed of a continuous strip of substantially non-stretching material, such as a thin ribbon of steel, which, when in taut relation on the pulleys I2 and 9, constitutes a traction device preventing any rotational movement of one of the pulleys without causing a corresponding rotational movement of the other of the pulleys. Thus the pulley 9, being fixed upon the shaft 8, any movement of the arm 6 about the shaft 8 will be accompanied by rotation of the pulley I2 about its shaft exactly equal to the angle through which the arm 6 has been rotated relative to the shaft 8. Thus any diameter of the pulley I2, relative to a corresponding diameter of the pulley 9, will always be maintained in parallel relation independent of movement of the arm 6.
To permit ready adjustment of the band 5 and to permit the band to be removed and replaced readily, the joint head I0 on the arm 6 is mounted upon the arm 6 for telescopic relation relative to the arm so that the effective length of the arm-that is the distance between the centers of the pulley 8 and the pulley |2,- may be extended or contracted by such telescopic movement. This may be readily accomplished by providing a boss or plug Inlc on the head I0 to extend snugly into the bore Bf of the tubular arm 6 and providing in such plug a threaded bolt |0d, the head IIIe of which is; provided with a slot engaged by an extending tongue IIJf on a block IOg rigidly secured in the bore of the arm 6 as by forming such block with a knurled outer Y surface and forcing the same in tight frictional engagement with the interior of the bore 6f. Thus by rotating the tubular arm 6, the bolt Id is screwed into or out of the block II'Ic, lengthening or shortening the distance between the centers of the pulleys 9 and I2.
At this point it should be observed that the single arm 6 constitutes a rigid support extending between the pulleys 9 and I2, which may be effectively lengthened or shortened to maintain taut relation between the pulleys and the band I5.
1a by a plug and bolt connection, corresponding to the plug |0c and bolt |0d, so that rotation of the tubular arm section 1 will also effectively lengthen or shorten this arm.
Upon the outer end of the arm 1 is a scale supporting head I1, the connection between the head I1 and the arm 1 being preferably identical with the connection between the arm section 6 and its head 6a. The head I1 is provided with a suitable bearing |1a pressed into a cylindrical opening I1b formed thereinto constitute a bearing upon which a protractor and scale supporting structure may be rotatably mounted. 'I'he protractor and scale supporting structure preferably includes a pulley I8 secured to a disk I9 which is in turn rigidly secured to a sleeve constituting a pivotal bearing engaging the ball bearing |1a held in assembled relation upon the head I1 by means of a suitable washer 2| and a locknut 22 threaded upon the upper end of the sleeve 20. Thus the flexible band I6 extending between the pulley I2 and the pulley I8 constitutes an interconnection of these pulleys similar to that formed by the band I5 between the pulleys 8 and I2, so that irrespective of rotational movement of the arm'1, relative to the shaft correspondingv parallel diameters of the pulleys I2 and I8 will always remain parallel.
Thus the scales or straight edges 4 and 5 may be secured to the pulley I8, irrespective of movement of the arms 6 and 1 over the board I, these scales or straight edges 5 being once aligned with a base line will always extend parallel to such base line, independent cf movement of the arm sections 6 and 1 over the board.
However, it is desirable that the scales or straight edges 5 should be capable of adjustment to angular positions relative to a given base line on the board I and for this purpose I have provided means for adjusting the scales 4 and 5 relative to the pulley I8 to permit the connection between the pulley and the scales to constitute a protractor. This may be readily accomplished by mounting the scales 4 and 5 upon an angular bracket 23 so that the scale 5 extends substantially parallel to the lower edge of the board I, while the scale 4 extends at right angles thereto.
'I'he bracket 23 may be secured to a plate 24 as by means of a pair of screws 25 and 26, the screw 26 being provided with a suitable handle 21 which permits ready loosening and tightening thereof so that by providing a slot 28 in the bracket 23 the relative angular position of the scales and the plate 24 may be readily adjusted; for example, if a drawing previously made is placed upon the board with its base lines not in accurate parallelism with the edges of the board, these scales may be adjusted through the medium. of the screws 25 and 26 to parallel them with the base lines of such drawing without disturbing the angular position between the plate 24 and the pulley I8.
The plate 24 is illustrated as being secured as by means of rivets 29 to a base plate 30 which is rigidly mounted upon a shaft 3| extending through the sleeve 20. The connection between the plate 38 and the shaft 3| is preferably made by squaring off one end of the shaft 3|, as indicated at 32, and riveting the same to a spring plate 33 which is in turn secured as by means of screws 34 to the base plate 30. The shaft 3| being rotatably mounted in the sleeve 20, permits rotation of the base plate with its scale bracket 23 relative to the pulley |8, so that by providing a graduated scale plate 35 interposed between the disc I9 and the pulley I 8, and providing a vernier plate 36 upon the plate 24, the scale plate 35 and the Vernier plate 36 having graduations 31 thereon corresponding to degrees of rotation, the relative positions of the base plate 38 and the pulley I8 may be set at any desired angle. For example, I have illustrated the scale plate 35 as having a zero calibration upon the vernier plate 36 so that by shifting the base plate 38, relative to the pulley, the zero calibration on the Vernier plate 36 may be aligned with any of the other calibrations on the scale plate 35 to conform with the angle desired between the straight edges 4 and 5 and the original base line upon which such scales may be set. f
However, in order to prevent accidental displacement of the base plate 30, relative to the pulley I8, and to provide for ready adjustment of the plate and pulley to commonly employed angles, such as 30, 45, 60 and 90, a plurality of holes 38 may be provided in the disk |9 to receive therein a pin 39 projecting from the spring plate 33. Thus when the zero calibration of the scale plate 35 and the vernier plate 36 are in alignment, the pin 39 will be received in one of the holes 38 to latch the base plate 38 and the pulley in this relation.
A suitable handle 48 may be mounted upon the upper end of the shaft 3| to permit relative rotation of the base plate 38 and the pulley I8 when the pin 39 is withdrawn and it is desired to move the base plate 38 to a new angular position, the handle 48 being preferably secured to a disk 4| which is received upon the upper end of the shaft 3| as by flattening the sides of the upper end of the shaft 3| so as to prevent relative rotation between the handle and the shaft.
rlo permit ready removal of the pin 39 from any one of the holes 38, I provide a finger-piece 42 pivotally mounted, as upon a shaft 43, set into a recess 44 and held therein by the plate 24, the finger-piece 42 being provided with a cam projection 45 such that when the finger-piece is `ro tated about its pivot 43 it will engage the upper surface of the plate 33 and depress the same to remove the pins 39 from the holes 38. With the spring plate 33 in this position, the base plate 38 and pulley I8 may be readily adjusted. However, if it is desired to lock the latching devices 39 and 38 out of effective engagement with each other, a lock may be provided, consisting of a locking plate 46 pivoted to the base plate 38, as at 41, and movable relative to the end of-the spring plate 33, as by means of a finger-piece 48 extending through an elongated slot 49 in the plate 24 so that after the spring plate 33 has been depressed the locking plate 46 may be moved over the outer end of the same to prevent the pin 39 from reengaging any of the holes 38.
With the latch 39-38 in this position, it may be desired to fix the angular positions of the base plate 38 and the pulley I8, and this may be readily accomplished by means of a clamping screw 58 extending through the base plate 38 and having a washer 5| thereon to be compressed into clamping relation upon the disc I9 by means of a nut 52.
It will therefore be observed that I have provided a drafting machine in which the scales are supported upon a protractor construction permitting them to be readily adjusted to any angular positions relative to a zero or base line, while, without disturbing the correct angular positions of the protractor mechanism, the scales may be adjusted independent thereof to a predetermined base line, already appearing upon a drawing.
It will also be observed that by employing the l single rigid arm section extending between the pulleys, and by employing the flexible bands, the correct alignment of the scales with the base line will be maintained independent of the movement of the arm sections over various portions of the drawing board. Also, by employing the continuous flexible bands as the traction means between the pulleys, it is possible to move the arm sections over all parts of the drawing board and, in fact, to rotate the same completely around the shaft 8 without interfering in any manner with the correct operation of the machine and without changing the true parallel relation of the scales with the predetermined base line upon which they may be set.
It will also be observed that by permitting complete rotation of the supporting arm sections about the shaft 8, it is possible for the scale supporting structure and protractor to be adapted for use either by a right-handed or a left-handed draftsman, and also permits the protractor to be supported upon any part of the drawing board, its connection to the bottom edge of the drawing board, rather than the top of the drawing board, or to either of the side edges of the board, being equally possible with my construction.
While I have shown and described the preferred embodiment of my invention, I do not wish to be limited to any of the details shown herein, except as defined in the appended claims.
I claim:
1. In a drafting machine, means attachable to a drafting board, an arm formed of a single tubular member having a pair of heads thereon at opposite ends thereof, pivot means mounting one of said heads to said attaching means for movement in a plane parallel to the surface of -said board, a pulley fixed to said pivot means, a second pulley rotatably mounted on the other of.
said heads for rotation in a plane parallel to the surface of said board, a continuous flexible band interconnecting said pulleys, and means threadedly engaging one of said heads in said tubular member for varying the distance between the centers of said pulleys to tighten or loosen said band.
2. In a drafting machine, means attachable to a drafting board, a pivot on said attaching means extending at right angles to the surface of said board, a pulley xed on said pivot means and extending in a plane parallel to the surface of said board, an arm comprising a single tubular member, a head on one end of said arm pivoted to said pivot means and having a stem extending into said tubular member in a direction at right angles to said pivot means, a second head threadedly secured in the opposite end of said tubular member, whereby rotation of said tubular member relative to said heads increases or decreases the eifective length of said arm, a second pulley pivoted to said second head for rotation in a plane parallel with the surface of said board, and a continuous iiexible band interconnecting said two pulleys.
VARD B. WALLACE.
US705725A 1934-01-08 1934-01-08 Drafting machine Expired - Lifetime US2051115A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2481666A (en) * 1946-03-05 1949-09-13 Vard Inc Strut construction for drafting machines
US2851779A (en) * 1955-05-16 1958-09-16 Joseph B Cox Angle adjusting means
US2979823A (en) * 1955-03-29 1961-04-18 Little Charles Hubbard Drafting board

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2481666A (en) * 1946-03-05 1949-09-13 Vard Inc Strut construction for drafting machines
US2979823A (en) * 1955-03-29 1961-04-18 Little Charles Hubbard Drafting board
US2851779A (en) * 1955-05-16 1958-09-16 Joseph B Cox Angle adjusting means

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