US1909289A - Drafting machine - Google Patents

Description

May 16, 1933. c. H. LITTLE 1,909,239

' DRAFTING MACHINE Filed Jan. 13, 1927 2 Sheets-Sheet 2 4 Lweutow:

161% fia m 3 Patented May 16, 1933 PATENT OFFICE I CHARLES H. LITTLE, OF CLEVELAND HEIGHTS, OHIO DRAFTING MACHINE Application filed January 13, 1927. Serial No. 160,840.

This invention relates to drafting machines and particularly of the well-known.

Universal type such as illustrated in numerous prior patents granted to me, among which might be mentioned No. 1,003,765 of September 19, 1911. This type of machine, as is well-known, has a parallel motion mechanism in the form of a jointed arm composed of two parallelograms, the end of one being adapted to be attached to an anchor either fixed to the drawing board or movable thereon, and the free end of the other carrying a protractor plate with a revoluble part circularly or angularly adjustable and having provision for receiving rulers disposed at right angles to each other. However, certain features of my invention are not confined to a machine having parallel motion mechanism of the specific form mentioned above.

The principal object of the invention is to provide certain improvements which simplify and reduce the cost of construction, increase the utility of the machine, and

render certain parts more compact and rigid thus increasing the accuracy and durability of the machine.

The invention comprises numerous improvements in the protractor end of the machine, these improvements permitting the protractor and rotatable ruler carrying arm to rest better and more solidly on the board, and bringing about a more compact arrangement and disposition of the chucks which a carry the rulers with reference to the axis of rotation of the ruler carrying arm relative to the protractor plate.

The invention may be briefly summarized as consisting in certain novel details of construction and combinations and arrangements of parts which will be described in the specification and set forth in the appended claims.

In the accompanying sheets of drawings showing an embodiment of the invention which operates very effectively, Fig. 1 is a plan view of the drafting machine applied to a drawing board; Fig. 2 is a side view of the protractor end of the machine; Fig.

3 is a central vertical sectional view of the same; Fig. 4 is a top plan view of the protractor end of the machine with the handle removed; Fig. 5 is a bottom view of the same; Fig. 6 is a fragmentary bottom view with certain parts removed; and Fig. 56 7 is a detail transverse sectional view along the line 7-7 of Fig. 4.

Referring now to the drawings, 10 represents the drawing board to which is applied the drafting machine which in principle 00- is similar to those illustrated in my prior patents, This machine is attached to the board through the medium of an anchor designated generally by the reference character 11. A. mid-anchor is herein illusw trated, this anchor being applied, to the upper part of the board between the top corners thereof. The drawing machine proper is attached to the outer end of the anchor 11 through the medium of an anchor plate 12 which is adapted to be quickly and detachably connected to the anchor. Pivoted to this anchor plate are the parallel rods 13 of the upper parallelogram, the

opposite ends of these rods, as well as the corresponding ends of'the parallel rods 14. of the second parallelogram, being pivotally connected to a common connecting or joint member in the form of an annulus or disk 15.

tractor plate to turn about the center thereas p of and provided with a handle 17 and two chuck arms 18 and 19 arranged at right angles to each other and having chucks to slidingly receive the chuck plates of a'pair of rulers 20 and 21, these generally consisting of scales or straight edges.

In this case, as is customary with midanchor machines, the axis of connection between the anchor plate 12 and the anchor is inclined with reference to the top edge of the board, and the point of attachment of the anchor plate to the anchor is removed some distance from the board which, under ordinary circumstances would leave the anchor, at all times, projecting a considerable 1 distance beyond .the board. This is undeportion 23 of the anchor from the relatively short-portion 22, but by pivoting or swinging the outer section on the inner section, the drafting machine may, when desired, be swung back along with the outer portion 23 of the anchor, close to and on an axis parallel to the board, as 'is often desirable but impossible with the ordinary mid-anchor. When the machine is in this position it is preferably supported on the anchor through the medum of a special supporting clip not shown.

The inner or base portion 22 of the anchor has two flanged ends which are attached to the edge of the board and an intermediate outwardly projecting part (forming twoshoulders, which are straddled by two cars 23a and. to which the part 23 of the anchor is pivoted. One pivot is formed bya pin 24 fixed in and projecting inwardly from one of the ears 28a. The other pivot is formed by a screw 25 projecting through the other ear, the inner ends of the pin 24 and of the screw 25 being preferably beveled and engaging in beveled openings in the shoulders of the base portion 22. The screw 25 may be provided with a lock nut when desired so that it will be possible not only to pivot one part on the other but also to quickly detach the two parts and to firmlyconnect them together and to insure the outer part being restored to the same place or position it occupied before removal.

One of the ears 23a; is provided with an extension 236 projecting overone of the flanged ends of the base portion 22 of the anchor so as to limit the upward swinging movement of the outer part 23 relative to the base part, and a cross bar 230 on the outer anchor member 23 carries a set screw 26 which is adapted to engage the middle portion of the base member 22 of the anchor to form an abutment which holds the outer anchor member in its normal extended position and serves also as a clamp to hold them in rigid relation.

The anchor end of the machine embodies numerous novel features whlch are more fully described and claimed in divisional application Serial No. 370,219, filed June 12, 1929.

The pivots for both ends of both pairs of rods 13 and 14, i. e., the pivots at both ends of both parallelograms, are preferably formed by balls, that is, are ball pivots, but asno claim is made herein to the details of these joints, it will be sufficient to state that at both ends of the two parallelograms the rods and members to which the rods are pivoted are held against ball pivots by spring pressure. At the protractor end, the rods 14 are pivotally connected to the protractor plate 16 or to an extension 16 thereof by the said ball pivots with the parts yieldingly pressed together and held under tension by a spring plate 42 overlyin the ends of the rods, the spring pressure ing obtained by a screw 43 lying centrally between the pivots and passing through the spring plate 42 and into the protractor plate extension 16 the latter consisting of a plate fastened by screws or otherwise to the lower side of the protractor plate. This same plate 42 is utilized in obtaining the yieldable pressure necessary to hold in assembled relation the parts forming the pivotal joint between the protractor plate and-the ruler carrying arm, as will be more fully explained presently.

Taking up'now the construction of the protractor and of the rotatable arm carrying thechucks which are adapted to receive the rulers 20 an 21, it will be observed that the chucks, and therefore the points of attachment of the rulers to the head, are brought much closer to the center of the protractor plate or axis of rotation of the arm than in my prior patent previously referred to, thus attaining not only to a marked degree the feature of compactness but adding considerably to the rigidity of the machine, particularly by reducing spring or bending as for example by pressure applied to the outer end of either ruler.

In the present construction, instead of positioning the chucks outwardly from the protractor and supporting them by a member projecting over the protractor late to the pivot point at the center thereo chuck 19 is extended inwardly beneath the protractor plate to and referably beyond the pivot point, and chuc 18 which is at right angles to the former not only lies in the plane of chuck 19 beneath the plane of the protractor but is attached to chuck 19 so close to the center of rotation of the head as to lie partially beneath the protractor.

Both chucks are secured to a common supportin member which is in the form of a flange stamping 45 having a flanged channel-like portion 45a in which is received and secured chuck 19, this portion being disposed radially with'respect to the rotractor and extending inwardly past t e center thereof, as clearly illustrated in the drawings. Additionally, this stamping 45 has 'a flanged channel-like portion 45?) which is at right angles to and somewhat shorter than the flanged or channel portion 45a,

and this second mentioned channel portion receives and has secured to it chuck 18 with the end of the latter abutting against the edge of chuck 19 (note particularly Fig. 5). The rotatable ruler-carrying arm includes, in addition to the lower stamping 45, an: upper su porting or attachin member which is pre erably in the form or a stamping 46 which overlies the protractor plate (note particularly Fig. 4). This stamping has a radially disposed portion directly above the main part of the stamping 45, this portion extending radially inward slightly beyond the' center of the protractor plate and having a punched opening with a beveled seat for the ball-pivot 47 by which the head is pivotally connected to the protractor plate. At the center where the protractor plate has a similar seat for the ball pivot, the parts are held together on opposite sides of the ball-pivot by an extension 42a of spring plate 42 which is pulled down to exert the requisite degree of pressure by a screw 48 disposed close to the joint.

The upper stamping 46 is somewhat T-' shaped and outwardly of the protractor plate it has a lateral extension'46a which has a depressed foot portion resting upon and secured by a screw 49 to the laterally extending channel portion 45b of the lower stamping 45.

The protractor plate has an open central portion inside of the arc-shaped grad uated peripheral portion and in this opening the lower and upper stampings are fastened together between the pivot and the graduated portion of the protractor, the fastening means preferably including overlapping frictionally engaging ears struck from the two'stampings, the upper stamping having marginal, downturned ears 46?) which closely engage ears 450 struck up from the body portion of the lower stamping 45. By these en a ing ears inside the graduated portion 0 t e protractor plate and by the attachment between. the stampings outside of the protractor, the two stampings are firmly secured together without any liklihood of relative movement between them and making a very substantial arm for supporting the rulers.

The outer extension of the upper stamping 46a carries a spring actuated latch 50 having a nose adapted to snap into any one of a series of notches 16b which may be either milled or punched in the peripheral portion of the protractor plate, and additionally it carries a rotatable protractor member 51 having an indicating line 51a adapted to cooperate with the graduations of the protractor plate, and still further it carries a clamp similar to that illustrated in my prior patent to hold theruler carrying arm inany desired position intermediate the positions determined by the notches 167), this clamp consisting of a screw 52 with a slotted head which receives the periphery of the protractor plate 16 and having a threaded upstanding stem extending through stamping 46 and engaged by a nut 53.

Above the protractor plate and disposed centrally with respect thereto, the handle 17 previously referred to, is provided, this handle being secured to the upperstamping 46 of the ruler carrying arm by a pair of screws 54 which extend from beneath (see Fig. 3) through both stampings 45 and 46, as well as through chuck 19. These screws serve also to tightly bind together the inner portions of the two stampings forming the ruler carrying arm.

In order that the protractor end of the machine may be firmly and squarely supported on the drawing board, there is attached to the lower side of chuck 19, preferably by means of the screws 54, a strip 55 of suitable material, preferably wood, the bottom of which is in the same plane. with the bottom of the rulers 20 and 21 (note Fig. 2) when supported in the chucks, this member constituting in efi'ect a continuation or extension of ruler 21.

As the strip 55 rests upon the drawing paper and in fact is the part through which the weight of the draftsmans hand is transmitted to the paper, it is very desirable that it be formed of a material which will have the least soiling action on the paper. For that reason, wood instead of metal is employed. formed separately from the chuck 19, that reason being that it is very important that the bottom of the strip 55 and the bottom surfaces of the rulers rest squarely and evenly on the drawing board or the drawing There is another reason why it is paper and in case there should be a varia- I By this construction not only are the rulers brought in much closer to the center of rotation of the ruler carrying arm about the center of the protractor plate, but as the rotating arm instead of the protractor plate rests upon the board and in fact constitutes the support for the protractor end of the machine, the lower side of the arm formed by the strip 55 and the lower sides of the rulers form a more or less unitary widely extending support having stability and firmness to a far greater degree than heretofore, it being noted that the rotatable part is thus stably supported on the board independently of the parallel 'ruler mechanism which is not true of prior constructions wherein the support for the ruler carrying arm has been through the protractor plate or some other non-rotating part. 9

Having thus described my invention, I claim:

1. A. drafting machine comprising a parallel motion mechanism carrying a protractor plate, and a ruler connected to the protractor plate and adapted to be supported by the drawing board to which the machine is attached independently of the parallel motion mechanism, and connecting means comprising a ruler-holding member for supporting the protractor plate on the board,

said member having a board-engaging por-- tion spaced beneath the protractor plate and extending axially of the ruler.

2. A drafting machine comprising a parallel motion mechanism having a protractor plate, and a ruler-supporting arm having upper and lower spaced parts, the upper part only having a pivotal connection with the plate and the lower part forming a board-engaging member beneath the plate.

3. A drafting machine comprising a parallel motion mechanism provided with a protractor plate, and a ruler-supporting arm rotatably connected to the plate and having portions extending inwardly one beneath and one above the plate, said portions being connected together outside of the periphery of the plate and also connected together Within the said periphery laterally of the center of the plate.

4. A drafting machine comprising a protractor plate, a parallel motion mechanism attached thereto for connecting the same to a drawing board, and a ruler-supporting arm having an upper portion pivotally connected to the plate at the center thereof and having a lower board-engaging portion extending beneath the protractor plate and below one parallelogram adapted to be connectedto a drawing board, a protractor plate connected to the free end of the other parallelos gram, and a ruler-supporting arm pivotally connected to the protractor plate and composed of two stampings, one carrying rulerreceiving chucks at right angles to each other and extending inwardly beneath the protractor radially thereof, and the second being secured to the first named stamping and ex tending radially of the protractor over the "same. v

In testimony whereof, I hereunto aflix my signature. v CHARLES LITTLE.

the center thereof and a'handle rigidly secured to said upper portion of the arm concentrically with the pivotal connection between the upper part of the arm and plate.

5. A drafting machine composed'of two' connected parallelograms, the free end of one parallelogram adapted to be connected to a drawing board, a protra'ctor plate connected to the free end of the other parallelogram, and an arm pivotally connected to the protractor plate and comprising a member having two integral flanged portions forming channels at right angles to each other and achuck member received in each of said flanged portions.

6. A draftin machine composed of two connected para lelograms, the free end of one parallelogram adapted to be connected to a drawing board, a protractor plate connected to the free end of the other parallelo-v gram, and a ruler-supporting arm pivotally connected to the protractor plate and comprising a member having two integral flanged portions at right angles to each

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