US2650429A

US2650429A - Curve scriber

Info

Publication number: US2650429A
Application number: US294838A
Authority: US
Inventors: Debs Victor
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-06-21
Filing date: 1952-06-21
Publication date: 1953-09-01
Anticipated expiration: 1970-09-01

Description

Sept, 1, 1953 v. DEBS CURVE SCRIBER Filed June 21, 1952' INVENTOR V/CTOR DEBS BY ATTORNEY Patented Sept. 1, 1953 UNITED STATES PATENT OFFICE CURVE SCRIBER Victor Debs, Ridgewood, N. Y.

Application June 21, 1952, Serial No. 294,838

5 Claims. 1

This invention relates to a curve scriber, and more particularly to an instrument which will scribe a Variety of mathematical or geometrical curves. The invention is especially useful in scribing ellipses, ovoid forms and spirals, to which uses, however, it is not restricted.

A variety of curve-scribing instruments have heretofore been designed and constructed, and some of such instruments have actually been put upon the market. However, such instruments have generally been complicated and expensive. They have also been delicate, difiicult to adjust and to keep in adjustment; and they have been subject to inaccuracies due to entrance of the human equation into their operation.

I have now constructed a curve scriber which is simple, inexpensive and rugged. Adjustment of the instrument with respect to character and size of the curve to be scribed is easily and accurately made, and is retained with certainty. Furthermore, a scriber according to the invention is so constructed that the human equation enters to a minimum extent into its operation.

According to the invention, means is provided whereby the marking element of the scriber is maintained at all times in perpendicular position with respect to the surface upon which the curve is to be scribed. Furthermore, means is provided for insuring a constant and even pressure of the marking element upon this surface. Finally, the invention provides means which compensates any unevenness in tension which a user may apply to the scriber during its operation, thereby minimizing the effect of the human equation in using the instrument.

The invention contemplates other advantageous and novel features, as will appear from the present specification.

One form of the invention is shown by way of illustration in the accompanying drawings, in which Fig. 1 is an elevation, partly in section, illustrating a curve scriber constructed and arranged according to the invention, the curve scriber being set up to scribe an ellipse which is shown in perspective;

Fig. 2 is a longitudinal horizontal section of the curve scriber shown in Fig. l, the section being taken on the line II-II of Fig. 1;

Fig. 3 is a vertical section taken on the line III-III of Fig. 1, viewed in the direction of the arrows, most of the apparatus appearing in elevation;

Fig. 4 is a perspective view of one of the specially-formed pins used with the curve scriber;

illustrated in Figs. 1, 2 and 3, there is shown a curve scriber Hi, comprising a standard H, a bracket i2 hinged to the standard, and a marking element holder I3 slidably carried by the V bracket ['2 for movement toward and away from the standard H. A marking element 14 is reciprocably mounted in the marking element holder l3 for free vertical movement therein. Thus the standard I l and the marking element [4 are swiveled with respect to each other by means of the bracket l2 and the marking element holder [3, and the slidable mounting of the holder in the bracket permits the standard and the marking element to be brought closer together or to be farther separated.

The standard ll comprises a circular foot l5 having a plane annular lower surface [6 adapted to rest slidably upon a plane surface, as the upper surface of a piece of paper upon which the curve scriber I0 is used. A central concave portion l! at the bottom of the foot l5 insures against wobbling of the foot when it rests upon the plane surface. A shaft 18 is fixed centrally in the foot l5 and extends perpendicularly therefrom when the foot rests upon a horizontal surface; and a sleeve [9 is closely fitted upon the shaft for rotation thereon. The bracket I2 is fixed to the sleeve l9, which hinges the former to the standard. Finally a handle 20 is fixed to the upper end of the shaft I 8 beyond the sleeve IS in order that the standard may be moved about on the horizontal surface.

The bracket l2 comprises two vertical parallel plates 2| and 22 integrally connected together by a web 23 across their upper edges. The parallel plates 2| and 22 are fixed to the sleeve I9 as by

welds

24 and 25 respectively (see Fig. 2) and extend horizontally from the sleeve. Thus the bracket I2 is free to move with the sleeve [9 pivotally about the shaft I8. The plates 2| and 22 have parallel slots 26 and 21 therein extending longitudinally thereof at right angles to the axis of the sleeve 19 from points adjacent the

welds

24 and 25 to the ends of the plates.

The marking element holder l3 comprises a tubular member 28 which is fixed to the end of a forked member 29 as by welds 35 and 3!. (See Fig. 2.) The forked member 29 has a pair of legs and 33 which are separated by a sufficient distance to enable them to fit closely, but slidably between the plates 2! and 22 of the bracket 52. Furthermore, the

legs

32 and 33 have slots 34 and 35 respectively therein which register with the slots 26 and 21 in the plates 2! and 22 respectively. However, the slots 34 and 35 are made wider than the slots 25 and 21 for a purpose which will later appear.

A pin 35 extends through the unslotted ends of the

legs

32 and 33 remote from the holder l3, and fits slideably into the slots 25 and 21 in the plates 2| and 22 to guide the forked member 29 as it slides back and forth in the bracket l2. A second pin 31 of larger diameter than the pin 36 extends through suitably enlarged portions of the slots 25 and 21 in the plates 2| and 2-2 and also through the slots 34 and 35 in the forked member 29 for a purpose which will later appear.

Split rings

38 and 39 snap in well known manner into circumferential grooves (not shown) in the second pin 31 immediately beyond the outer surfaces of the respective plates 2! and 22 to fix the second pin 31 in position during operation of the curve scriber. Thus the

pins

36 and 31 constrain the forked member for motion at right angles to the shaft I8.

A helical compression spring 45 is disposed between the end of slots 34 and 35 of forked member 29 and the pin 31 in the space between the

legs

32 and 33 of the forked member 29, the diameter of the spring being such as to cause a part thereof to extend partly into each of the slots 34 and 35, whereby the spring is steadied.

From the foregoing it will be evident that sliding movement of the forked member 29 in the bracket 12 away from the sleeve 19 will be resisted by the resiliency of the compression spring 40. Moreover, by removing the

split rings

38 and 39 from second pin 31, that pin may be withdrawn, and the helical compression Spring 40 released. The marking element holder ['3 may thus be separated from the bracket l2.

The marking element M has a cylindrical stem 4| thereon which fits closely but slideably into the tubular member 28. A transverse pin 42 fixed in the stem 4| of the marking element extends outwardly through a longitudinal slot 43 in the tubular member 28 to prevent turning of the marking element in the tubular member; and a weak sprin 44 is compressed within the tubular member between its closed top and the top of the stem 4! to urge the marking element gently out of the tubular member, that is to say downwardly. As here shown, the top of the tubular member comprises a threaded plug 45, whereby the force exerted by the weak spring upon the top of the cylindrical stem 4| may be adjusted. Accordingly, when the lower surface IQ of the circular foot rests upon the paper or other surface upon which a curve is to be scribed, the marking element M will make suitable contact with the paper or surface, through the force of gravity and the gentle urging of the weak spring 44, Thus means is provided for insuring a constant and even pressure of the marking element upon the surface upon which the curve is being scribed.

The slot 43 has a transverse hooked extension 455 at its upper end thereby making it possible to move the marking element inwardly of the tubular member 28 against the resiliency of the weak spring 44 and, by turning the marking eled ment, to hold it upwardly in the holder 13 out of contact with the surface upon which it acts. In such inoperative position, there is no objection to having the marking element turned in the tubular member 28.

The curve scriber is operated in conjunction with a loop of thread in a manner later to be described. For this purpose a thread reel 41 is mounted upon a bracket 48 fixed in known or convenient manner to the tubular member 28 at the opposite side thereof from that hearing the welds 3E! and 3i. The bracket 48 is a forked member the legs of which extend away from the tubular member, each leg having a round opening 49 therein for reception of a split shaft 50 of the thread reel 41. A knurled head 5! at one end of the split shaft provides means for turning the thread reel in the bracket 48. A looped thread 52 is wound about the split shaft 56 of the thread reel between the forks of the bracket 48 and extends thence through an opening 53 in a downwardly extending guide member 54 forming part of the holder [3. Passing along the guide member 54 the thread 52 passes through a terminal slot 55 at the lower end of the guide member 54, whence the looped thread extends horizontally away from the marking element l4 and the standard H to engage a plurality of double conical location elements 56 (see Fig. 4). The double conical location elements 55 are each formed with a central waist 51 and opposite terminal cone bases 58; and a pin 59 is positioned centrally of each terminal cone base 58 for insertion into the surface upon which the curve is to be scribed to position the location element thereon. The double conical elements 56 are so formed that, when positioned upon the surface upon which a curve is to be scribed, their central waists 51 will be at the elevation above the surface at which the standard H supports the terminal slot 55 of the guide member 54.

In the embodiment illustrated in Fig. l the curve scriber is shown as set up for scribing an ellipse, the marking element 14 being illustrated as a draftsmans pen. The curve scriber is used todescribe an ellipse in the following manner: Two of the double conical location elements 56 are positioned at the foci of the ellipse to be scribed. To this end a pin 59 of each element is thrust through the paper upon which the ellipse is to be drawn and into the drafting board beneath it until a terminal cone base 58 of each element rests evenly upon the upper surface of the paper. Thereupon the neck of the reversely conical location pins is at the elevation of the terminal slot 55 of the guide member 54 when the circular foot l5 of the standard H rests upon the same surface. The doubled or looped thread is next partially unwound from the thread reel 41, drawn a sufficient distance through the opening 53 and the terminal slot 55 in the guide member 54, and looped about the

central waists

51 and 51 of the two double conical location elements 56 and '56. The marking element I4, which has been partly withdrawn into the tubular member 23, with its transverse pin 42 in the hooked extension '46 of the longitudinal slot 43, is now turned and allowed to move partly out of the tubular member. In effecting this, the transverse pin 42 slides in the longitudinal slot 4-3, and remaining in the longitudinal slot, prevents the marking element from turning in the tubular member. The scribing point of the marking element I 4, as the marking end of the pen illustrated in Fig. 1, is now placed at one end of the major axis of the ellipse to be scribed. Thereupon the knurled head is turned to wind any slack in the thread 52 upon the split shaft 50 until the thread is pulled gently taut about the

central waists

51, 51 of the double

conical elements

56, 56 and through the terminal slot 55 of the guide member 54. In this condition the looped thread extends horizontally above the paper.

Grasping the handle 20, the standard H is drawn slightly away from the marking element holder l3, compressing the helical spring 40 to a limited extent. This is possible because the marking element holder is restrained by the tension of the thread 52 which is looped about the double conical elements 56. Maintaining substantially even tension in manipulating the handle 20, the standard II is moved completely around the two double

conical location elements

56, 56, causing the marking element I 4 to scribe the ellipse. The size and character of the ellipse is, of course, governed by the distance between the double conical elements and by the length of the looped thread between the farthest double conical element and the guide member 54.

The circular foot I5 and the shaft l8 extending vertically therefrom provide means whereby the marking element I4 is maintained at all times in perpendicular position with respect to the surface upon which the ellipse is scribed. Inaccuracies in scribing the ellipse which might result from holding the marking element at an angle to the vertical are thus avoided. Furthermore, the force of gravity upon the marking element M, which is freely slidable in the vertically-positioned tubular member 28, plus the action of the weak spring 44 upon the marking element insures a constant and equal pressure of the marking element upon the surface on which the curve is being scribed. Finally the relationship of the marking element holder and the standard, together with the action of the compression spring 40, provides means which compensates any unevenness in tension which a user may apply to the scriber during its operation. Thus, little variation results in the tension applied to the looped thread 52, and the looped thread is not stretched. The efiect of the human equation in using the instrument is accordingly minimized.

Instead of drawing the curve with a draftsmans pen as illustrated in Fig. 1 it may be desired to draw the curve in pencil. A marking element for this purpose is illustrated in Fig. 5, a pencil holder 60 of known form being there illustrated with a lead 6| releasably held therein. The same type of cylindrical stem 4| is fixed to the pencil holder 66 as is fixed to the pen illustrated in Fig. 1, and the same type of transverse pin 42 is fixed to the cylindrical stem 4| for the same purpose as that heretofore described.

Fig. 6 illustrates how the curve scriber may be employed to scribe the ovoid form there illustrated. For this purpose double conical location elements 56 are inserted at points A, B and C, which are spaced to provide the desired scribed form. The thread 52 is looped around the central waists 51 of these location elements, adjustment of the length of looped thread is made by turning the knurled head 5| and the standard I l is moved around the location elements in order to scribe the ovoid form.

In Fig. 'l a method of scribing a spiral curve is illustrated. In this case four double conical location elements 56 are positioned at points W, X, Y and Z closely together. The thread 52 is looped over but one of the location elements,

and the length of the looped thread is suitably adjusted. The spiral is then scribed by giving wound from them. The result is a spiral curve such as that illustrated.

Obvious methods of scribing other curves may, 'of course, be employed.

From the foregoing it will be apparent that the present invention provides a simple, inexensive and rugged curve scriber which is easily adjusted and used to scribe a variety of different curves. Because of the simplicity of its adjustment, that adjustment is retained without difficulty. Furthermore, the curve scriber minimizes the effect of the human equation in using the instrument.

The form of the invention here described and illustrated is presented merely as an example of how the invention may be embodied and applied. Other forms, coming within the proper scope of the appended claims, will readily suggest themselves to those skilled in the curve scribing art.

I claim:

1. A curve scriber comprising: a standard including a foot having a plane lower surface adapted to rest slidably upon the surface upon which a curve is to be scribed, and a shaft fixed to said foot and extending perpendicularly therefrom; a bracket hinged to said shaft, said bracket including two parallel plates; a marking element holder slidably connected to said bracket for motion at right angles to said shaft; a marking element slidable in said marking element holder in the direction in which said shaft extends to contact the surface upon which the curve is to be scribed with its scribing end; and a looped thread adjustably connected to said marking element holder for looped connection about a plurality of location elements to determine the changing position of said marking element while scribing a curve.

2. A curve scriber comprising: a standard including a foot having a plane lower surface adapted to rest slidably upon the surface upon which a curve is to be scribed, a shaft fixed to said foot and extending perpendicularly therefrom, and a sleeve closely fitted upon said shaft for rotation thereon; a bracket fixed to said sleeve, said bracket including two parallel plates; a, marking element holder slidably connected to said bracket for motion at right angles to said shaft; a marking element slidable vertically in said marking element holder to contact the surface upon which the curve is to be scribed with its scribing end; and a looped thread adjustably connected to said marking element holder for looped connection about a plurality of location elements to determine the changing position of said marking element while scribing a curve.

3. A curve scriber comprising: a standard including a foot having a plane lower surface adapted to rest slidably upon the surface upon which a curve is to be scribed, a shaft fixed to said foot and extending perpendicularly therefrom, and a sleeve closely fitted upon said shaft for rotation thereon; a bracket fixed to said sleeve, said bracket including two parallel plates; a, marking element holder slidably connected to said bracket for motion at right angles to said essence a shaft; said marking "elementholder including a vertical tubular member, a forked member fixed to said tubular member and spring-restrained between said parallel'plates, and a thread reel; a marking element slidable vertically in said tubular member to contact the surface upon which the curve is to be scribed with its scribing end; and a looped thread adjustably connected to said thread reel for looped connection about a plurality of location elements to determine the changing position of said marking element while scribing a curve.

4. A curve scriber comprising: a standard including a foot having a plane lower surface adapted to rest slidably upon the surface upon which a curve is to be scribed; a bracket hinged to said standard to swing completely thereabout in fixed horizontal position; a marking element holder slidably connected to said bracket for motion at right angles to said standard, said marking element holder including a vertical tubular member, a thread reel, and a downwardly extending thread guiding member having an opening and a terminal slot therein; a marking element slidable vertically in the vertical tubular member of said marking element holder to contact the surface upon which the curve is to be scribed with its scribing end; and a looped thread connected to said thread reel and passing through the opening and the terminal slot in said thread guiding member for looped connection about a plurality of location elements to determine the changing position of said marking element while scribing a curve.

5. A curve scriber comprising: a standard including a foot having a plane lower surface adapted torest' slidably on the surface upon" which a curve is to be scribed; a bracket hinged to said standard to swing completely thereabout in fixed horizontal position; a marking elements holder slidably connected to said bracket for motion at right angles to said standard, said marking element holder including a, vertical tubular member, a thread reel, and a downwardly extending thread guiding member having an opening and a terminal slot therein; a marking element slidable vertically in the vertical tubular member of said marking element holder to contact the surface upon which the curve is to be scribed with its scribing end; a plurality of double conical location elements in ended for fixation at suitable points on the surface upon which a curve is to be scribed; and a looped thread connected to said thread reel and passing through the opening and the terminal slot in said thread guiding member for looped connection about said plurality of location elements to determine the changing position of said marking element while scribing a curve.