US1909291A

US1909291A - Drafting machine

Info

Publication number: US1909291A
Application number: US370219A
Authority: US
Inventors: Charles H Little
Original assignee: Individual
Current assignee: Individual
Priority date: 1927-01-13
Filing date: 1929-06-12
Publication date: 1933-05-16
Anticipated expiration: 1950-05-16

Description

May 16, 1933. c. H. LITTLE DRAFTING MACHINE Original Filed Jan. '15, 1927 2 Sheets-Sheet 1 C. H. LlTTLE DRAFTING MACHINE May 16, 1933.

Original Filed Jan'. 13 1927 2 Sheets-Sheet 2 Patented May 16, 1933 UNITED STATES PATENT orrlclaz CHARLES H. LITTLE, or CLEVELAND HEIGHTS, OHIO naarr'ine MACHINE Original application filed January 13, 1927, Serial No. 160,840. "Divided and this application filed June 12,

' 1929. Serial No. 370,219.

This invention relates to drafting machines and particularly to drafting machines 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 ointedarm 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 Tight angles to each other. However,-certain featuresof my invention are not confined to a machine having parallel motion mechanism of the specific form mentioned above. This application is a division of my prior application Serial No. 160,840, filed January 13, 1927. 3

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 anddurability of the machine. v

The present invention relates to certain improvements in the anchor andthe anchor end of the machine and particularly to-the construction-of the anchor and of-the anchor plate forming a par-tof the parallel motion mechanism and in the manner of attaching the machine to the anchorand detaching it therefrom, :as well as in the provision of means by which the machine in folded condition but still attached to-the anchor may be supported by the anchor at the back and parallelt'o the top edge of the board.

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 View looking toward the topedge of the drawing board-and-showing the machine foldedland supported by the'anchorat the back. and parallel to the top edge of the board;Fig. 3 is a side elevation of the anchor end of the machine looking in the direction (if the arrow designated :3 in Fig. 1; Fig. 4 is a sectional view substantially along the line 4 4; of Fig. 1; Fig. 5 is an end View of the anchor and certain of its associated parts looking in thedirection of the arrow designated 5 in Fig. 1; Fig. 6 is a bottomiview of the anchor end of the machine; Fig. 7 is a transverse sectional view substantially along the'line 77 of Fig. 3; Fig. 8 is a plan view showing a portion of the draw; ing board and showing the anchor'and a portion of the machine proper before the outer section of the anchor is swung down to the position shown in Fig. 2; Fig. 9 is a view looking at the top edge of the board and showing the anchor in the position shown in Fig. 2; Fig. 10 is a detail sectional view substantially along the line 10-10 of Fig. 8;-and Fig. 11 is a similar sectional view substantially along the line 11-11 of Fig.9. f'

Referring now to the. drawings, 10 represents the drawing board to which is'applied the drafting machine which in principle is similar to those illustrated in myv prior patents. This machine is attached to the board through the medium of an anchor designated generally by the reference character 11. This part, as well as others now briefly referred to, embodies detail improvements which will be taken up later. A midanchor is herein illustrated, this anchor being applied to the upper part of the board between the top corners thereof. -The drafting machine properis attached "to the outer end of the 1 anchor 1'1 through the medium ofan anchor plate '12 which is of novel construction and 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 100 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.

The lower or outer ends of the rods 14 are pivotally connected to the protractor plate 16 attached to a ruler supporting mem: her or arm pivotally connected to the protractor plate to turn about'the center thereof and provided with a handle 17 t and two

chuck arms

18 and 19 arranged at right angles to eaclrother 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 0f1connection between the. anchorplate 12. and the anchor. is inclinedwith'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. alltimes projecting a. considerable distance beyond the-board: This isundesirable'for certain uses, as, forcexample, for college or schoolroomuse where the boards vare stored when not-in use and where as-smalha compass as possible. is desirable. Accordingly, the anchor is made. in two sections.22 and 23, the former. being in this instance. attached towthe top edge of: the board and the latter'being not only detachably connected ftO it -but also havingpivotal connection therewithalong an axis parallel to the top edge OfitllB board. It..is,. therefore, not onlypossibleto detaclnthe longer portion 23 of theanchor from therelatively short portion 22, but;by pivoting .or swin ingUthe-outer section onthe inner section, the drafting machinev may, when desired; be swung :back along with the outer portion 23 of theanchorclose to and on anaxis parallel to the board, as is often desirable but impossible. with. the. ordinary midaanchor. When the machine is in thisposition, it is preferably supported on theanchorjthzrough the. medium of aspecial supporting clip .to

be. described below inv connection with Fig. 2.

. Theinner-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 two shoulders,.which are straddledby. two ears 23a and to which the part 23 of'the anchor is pivoted. One pivot is formed bya pin'24 fixed in and projecting inwardly fromone of the ears 23a. The other pivot isformed by a screw 25 projecting through the other ear, the inner ends of the pin 24 andof the screw 25 being preferably beveled and. engaging in beveled'openings inthe shoulders ofthe base portion' 22. Thescrew 25 may be; provided witha lock nuttwhen 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 firmly connect them together and to insure the outer part being restored to the same place or position it. occupied before removal;

One ofthe ears 23a isprovided with an extension 23?) projecting over one of the flanged ends of the base portion 22 of the anchor so as to limit theupward swinging movement of the outer part 23 relative to the base part, and a cross bar 230 on the outer: anchonmember. 23- carries a. setscrew. 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 5S8IV6S also. as a clamp to. hold them in rigid relation.

As explained above, .with this mid anchor formed in .two. pivoted sections it is possible toswing or. fold the machine back parallel to and along'thetop. edge oftheboard-and it. was Y previously pointed outthati when :the

machine. is. swung back to. this position .it; is i preferably. supported :on the anchor, .thetwo arms o.f:the, parallelogram then .beinggfolded together. To enable the. anchor;: to support the: machin e; in :this position, it;need only 5 be provided a with La. supporting hook on which the. protractor. end of 'thewmachine may engage andbe; supported.. I have-illustrated this in .Fi gs. 2,: .8, .9, .10 and 511 showingrcertain views ofzthe anchor and illustratirrgthe machine folded backvand supported in; the p.osition.stated.:. This hook, which has been omitted from Fig-.1 forthe:sakeioftclearness, is preferably in the form ofiastampihgflfid pivcrtedbyra-screw 236 01 equivalent means to. :the. bar 230 ofrthesoute-r. anchor member 23;.v \Vhenthe machine is in' use; on; the board, this-hook. is, ofa course, not required and normally. itis folded in and liesscloseto thecross bar230so asnot to interfereiwith the free movement of the upper;- parallelogram;

rods .13, but: this stamping .cairbe swung outwardto serve. asa hook-like support (see Fig. 11 )ifor.-the protractorrend of-the mar chine-when -.the machine is swung.:' back :be-

YGDd'iZLIld. i'parallel stoothe upper: edge; of" the:

board, as.illustrated in Fig.q2,..thisi hook being. so positioned: when. theemachine is swungto the position stated that .it: may: be engaged-by one of-the rods l tofthea-outer parallelogram or. other: appropriateipart.

Taking up next. the construction of the anchor plate 12andtheparts associated with it, this anchor plate, as. illustrated :in Figs. 4and 5, has at :itsendsdownturned ears 12a and. .126, the ear 12a. having. an inwardly ex:- tending-pivot27, "and car "1212' carrying.- anushaped spring actuated lever'28'with apivot 29 (Fig. 5) disposed oppositelyrwith respect to the-pivot 27. The pivots-27 and-29'are adapted to engage. in journals or: trunnions tion between the anchor and the anchor plate is at an angle with respect to the top edge of of the drawing board. V I The lever 28 is preferably in the form of a stamping one end of which projects upwardly above the anchor plate so that it can be conveniently grasped and pressed inward by the draftsmans finger to separate the

pivots

27 and 29 so that the machine canbe readily attached to or detached from the anchor. The pivot 29 is preferably a lug or boss struck from one side of the inner part of the lever, and'above this lug there are a pair of similar lugs 31 struck from the opposite side, these two lugs bearing against the inner side' of ear 12b and constituting the fulcrum about which the levermay rock. A coil spring 32 actingon the lever holds the pivots in engagement with the journals or trunnions of the anchor, this spring surrounding a screw 33 extending beneath plate 12 through the cars 1202 and 12b and freely through the upper part of the inner portion of lever 28. This screw not only supports the spring but strengthens and increases the rigidity of the plate.

To attach the machine to the anchor, it is only necessary for the operator to press in on the upper end of the lever 28 so as to separate the

pivots

27 and 29 and after the latter are brought into alignment with the trunnions at the outer end of the anchor, to then release the lever 28, whereupon the anchor plate is attached to the anchor with a snap action. In this way the machine not only can be attached quickly to the anchor but, as it is unnecessary for the draftsman to manipulate a screw to attach the machine, there is no danger of the machine being attached to the anchor either too tightly or too loosely, as might be the case if the connection were made by tightening a screw, particularly when the machine is in the hands of an inexperienced or careless draftsman, and when the machine is applied, it comes back to the same place it previously occupied, making it unnecessary to realign the machine or drawing.

The end of lever 28 lies along the upper left-hand end of plate 22 of anchor plate 12 as the same is viewed in Fig. 1. The location of the upstanding end of the lever at this point not only makes it convenient for the operator to manipulate the lever with his thumb while his hand is holding the anchor plate in applying or removing the machine, but as it is located at the end of the plate remote from the board, it does not reduce the clearance ofthe free movement of the ruler 20. It might be here stated also to be transmitted to the anchor. I done, in this instance, through the medium that by arranging the pivots of the anchor plate 12 011 the inner sides of downturned ears of the anchor plate, the pivot points are below and substantially no closer to the board than the pivots :tor the rods 13, so that by'this construction, including the location of the lever 28, substantially maximum clearance is obtained for a given length of mid-anchor.

The rods 13 of the upper parallelogram are pivotally connected to the under side of anchor plate 12 through the medium of ball-pivots 34:, this same type of joint being provided for both ends of the two sets of

parallel rods

13 and 14;. The ballpivots engage in openings in the anchor plate 12 and rods 13, and, at the anchor end of the machine, and, in fact, at each end of the two parallelograms, the rods and members to which the rods are pivoted are held against the ball-pivots by'spring pressure. At the anchor end of the machine the rods are pressed up against the ballpivots by a plate 35 lying parallel to and on the under side of plate 12 forwardly of the ears 12a and 12b, and this plate 35 is pressed yieldingly upward by a bowed piece of spring metal 36. To hold this-spring 36 under. tension and to adjustthe tension, a screw 37 passes centrally through plates'12 and 35 and through the spring 36, and'on the under side of spring 36 the screw has threaded engagement with a nut 38 preferably in the form of a stam ing having engaging an upturned foot 38a (Fig.

spring 36 plate 35 immediately behind whereby the nut is held from turning.

This one screw and the nut which engages it hold together all the parts forming the joints between the rods 13 and the anchor plate. g

It is desirable, of course, that the two parallelograms of the machine be held up off the board so that the protractor and the associated parts may be moved freely over the board, and this is generally accomplished by causingthe weight of the parallelograms This is of an adjustable abutment 39 which, for the sake of simplicity of construction, isin theform of a bushing or nut screwed onto the'lower end of screw 37 and arranged'to engage the outer anchor member 23. The manner in which this bushing functionsto hold theparallelograms oil the board or to transmit the weight thereof to the outer portion of the anchor is clearly illustrated in Figs, 5 and 7. w

As the rods 13 and the disk 15 are held off the board in a plane substantially parallel thereto, there is a considerable overhanging weight transmitted through the outer ends of the rods 13 to the anchor plate, and it is therefore essential that the connections ment with the protractor between therods 13 andthe anchor plate have the necessary stiffness in a. direction at right angles to the board to hold the rods extending from the plate in the desired direction (in planes at right angles to the board). To enhance thev stiffness of the joints, the upper'edge of the plate 35 is provided with upwardly extending lugs or feet 35a which engage the under side of the anchorplate beyond the ends of the rods 13. This gives plate 35 more stability and greatly increases the stiffness ofthe joints in .adirection at right angles to the board.

Thus it will be seen that while the rods are supported by the upper anchor plate 12 they are directionally supported by the lower plate 35 which is held in place in such a way that it is free to adjust or accommodate itself to wear.

While the joints between the rods and the anchor plate have stiffness in a direction at right angles to the board, as explained above, the joints between the rods and the disk Y15 and at the protractor are semi-flexible or relatively flexible in the direction stated so as to allow the ruler arm toat all times rest solidly on the board and adjust itself to the irregularities thereof.

The adjacent ends of the two pairs of parallelrods 18 and 14 are, as previously stated, pivotally connected to the disk 15. The. pivotal connections at these points are formed as at the anchor end, and, in fact, also at the protractor end, by ball-pivots, the rods 13 being pivotally connected to the upper side andthe rods 14 to the lower side of thedisk 15. The two pairs of rod ends are pressed in engagement with the ball pivots and the latter are held in engagethe disk by two bowed springs 40 which are held under tension by centrally disposed screws 41 screwed into the disk or annulus. The protractor ends of the rods 14 are pivotally connected to the protractor plate 16 or an extension thereof by ball-pivots with the parts held yielding- 1y pressed together and held under tension by a suitable spring plate, not shown, overlyingthe ends of the rods. As the specific formof-connection between the rods 14 and plate, as well as the mode of pivotally connecting together the two parallelograms at the disk 15, forms no part of the present invention, further illustration of the same other than that shown in Fig. 1 is deemed unnecessary.

While I have shown the preferred construction of the anchor and of the parts forming the anchor end of the machine, the same being an embodiment which operates with high efficiency, I do not desire to be confined to the precise details shown but aim in my claims to cover all modifications which do not involve a departure from the spirit and scope of the invention.

Having thus described my invention, I claim: I

1. A drafting machine. of the parallel motion type having an anchor plate with a pair of'downturned ears having relatively spreadable pivot formingmeans for attachment to an anchor on the drawing board, the pivot formingmeans of one ear comprising.- a spring. actuated member with an operative portion adjacent the plate and adaptedto be shifted to spread the pivot forming means, 7 j

2. A drafting machine having a'parallel motion mechanism including. two parallel rods and an anchor plate to which the ends of the rods are connected, a member for holding said rods and the plate in'pivotal engagement, a screwextending through the plate and through said'member, and an adjustable supporting abutment on an'extension ofsaid screw to hold the rods off the oHA EsH; LITTLE.