US1604883A - Pantograph - Google Patents

Description

Oct. 26, 1-926. 1,604,883

. c. DEVE PANTOGRAPH Filed March 5, 1925 Patented 26, lent l.

earner CHARLES Drive, or PARIS, FRANCE.

PANTOGRAPH.

Application filed March The present invention appertains to improvements in reproducing or pantographic apparatus, and it has for its object to provide means which will permit of reproduction on any surface of any given pattern and on a reduced scale, this without distortion or deformation perceptible to the naked eye, and conversely, the reproduction of the pattern with amplification or enlargement when such is desired.

A further object in view is to provide such a construction of device that it may be employed to distort the original pattern in any given manner; for example, by changing straight lines of the pattern sketch into curved lines, with enlargement or reduction in size as desired.

One of the novel characteristics of the pantographic device forming the subject matter of this invention resides in the elimination of joints, making it easy to operate and to assemble, as well as to adjust. while the work produced by the same will involve the highest precision. The apparatus is very compact and simple as compared with apparatus capable of producing corresponding work.

In the illustration depicted in the drawing I have disclosed the apparatus as arranged to reproduce a pattern upon a piece of glass, but it will be obvious to those skilled in the art to which the invention relates that the reproduction operation applies equally well to other purposes or objects.

7 In the drawing:

Figure 1 is aside eleyation of the pantographic device with the work and pattern support with which it cooperates shown in section;

Figure 2 is a fragmentary plan view of the beam of the pantographic device showing more clearly the pin and slot connection employed in this apparatus.

On the main frame. B I provide a work support which may be of any of the well known types of holders for sustaining the object on which the engraving or reproduction is to be transposed, the work surface hereinafter referred to being designated V. Adjacent this work surface is disposed a pin or post P which constitutes a pivot mounting for the beam 1 of the pantographic device. This postmay be fixedly secured to the support B so as to project perpendicularly there-- from or it may be mounted for adjustment on support with relation to war 5, 1925, Serial No. 13,255, and in France May 17, 1924.

surface, as shown in the drawings, and this post may also be inclined with relation to the work s face, depending upon whether an inclination is desired, as for instance when a distortion of the pattern is to be produced.

Under some conditions it may even be necessary to give to the post P a certain degree of curvature, and these modifications are clearly within the purview of this invention.

The adjustment of the post with relation to the work surface V obviously controls the degree of reduction or enlargement and it may be arranged to cooperate with a movable scale, not shown, so as to permit rapid and accurate variations in the degree of reduction desired.

The beam 1 is slotted at its lower end as indicated a-t2 to receive the post or pivot P so as to permit relative swinging and sliding movements of the beam in the operation of this device. It will be understood that this mounting may readily be reversed by providing the beam 1 with a fixed pivot member havinga sliding connection with the frame B. so that I do not wish tobe limited to the specific form of connection which is depicted in the drawings so long as the freedom of movement referred to is obtained.

The beam 1 has mounted thereon a holder 4 adj ustably secured by means of the clamplng ew 5 and carrying at its extremity the engraving instrumentality 3 which in the instant case is a diamond. I desire it to be further understood that the character of tool which is mounted in the beam depends upon the nature of work which is to be done or the character of the material on which the scribing is to be effected. It may possibly be replaced by a Stanh-ope lens, a well known article, as hereinafter referred to. especially where reproduction of microscopical drawings or patterns is involved. Such a device essentially consists of a magnifying lens the contacting surface of which is provided with a marker by means of which to follow the pattern, and it is considered unnecessary to illustrate or further describe this feature of the apparatus in view of its well known characteristics. a, I

At the upper end, the beam is provided with a tracer arm 6 which projects at right angles and is provided adjacent its outer extremity with a tracing point 7 and a pencil holder or socket 3.5 to n; a mark. H

vpoint 3 on the surface V is disposed.

strument or pencil C. The arm 6 is capable of adjustment on the beam 1 so as to vary the -distance of this arm with reference to the scribing or engraving tool 3 whereby this may be brought closer together or separated, as the case may require.

The tracer rests upon and operates over the surface of the support 8 on which the drawing to be reproduced by the engraving It is to be particularly noted that the pattern support or surface is angularly related to the work surface V, this marking the essential departure from the usual arrangement in well known apparatus in which the two surfaces are generally disposed in parallel relationship to each other and to the plane of travel of the instrument.

It will be obvious that during the engraving by the point 3 the pencil C will make a faithful reproduction on the pattern surface of the design which is cut into the surface V, thus providing a duplicate of exactly what is engraved on the work surface. If the duplicate is not needed the pencil C may be displaced at will.

The tracer 7 may be arranged to cooperate with or slide in the grooves of. a vignette or a sheet of metal having a design cut thereinto and which may be placed upon the pattern support; these vignettes may be, for instance, trademarks, stamps, names 0 firms, etc.

It will be obvious that the extent of pressure of the engraving point upon the work surface will vary according to the degree of inclination of the beam 1 and it is therefore easy to regulate this pressure by giving the proper inclination to the frame B on which the post P and the pattern support 8 are ahixed. A movable counterweight 9 is attached to the lower or slotted end of the beam 1 and materially assists in the regulation of the pressure which is produced.

While the post P is of a size which will permit quite free movement of the beam in the operation of the device, any desired means, may be employed to eliminate side play whether this be by way of the provision of a weight or of a spring so arranged as tomaintain the contact of the beam against the post on the same side all times In the apparatus herein disclosed it will be apparent that the movements of the arm 6 around the pivot or post P will be reduced in the ratio of the respective distances of the scriber 3 and the tracer 7 to the post or pivot P. In addition, the movements of the tracer in the plane of the beam 1, are reduced by the engraving point 8, but the degree of reduction obtained depends upon the angle between the lines formed by the intersection of the vertical plane passing through the points 3 and 7 with the respective pattern and work surfaces, together with the progress of the tracer? in the cross plane. For example, one can give this angle a value such that the degree of reduction will be the same for the two movements.

It is easy to see that under these conditions the sketches or drawings obtained will not be similar but will be homographic. The pattern surface 8 may be such a manner that this homographic will be as near to correspondence with the pattern as possible. The theoretical shape which is to be given to the pattern surface 8 may be mathematically calculated; generally it is curved in two different directions but for practical purposes it is possible to use a spherical surface the center of which is in the neighborhood of the pivot.

One can also, through a judicious choice of the perameters of the instrument (table surface, shape and position of the pivot) systematically distort the original drawing. Thus, by choosing for the surface of the pattern support a proper degree of curva ture, coaxialwith the said pivot bases, characters inscribed on the parallel lines of the support will be engraved according to circumferences concentric with the pivot, and with a rate of reduction which increases when nearing the center. This arrangement is particularly suited for engraving on coins, metals or glass for Opticians, in which case, the object to be engraved is centered below the pivot.

One can. see that the engraving point 3 can be made to follow a sketch, traced beforehand on the surface V, and in this case the pencil point in the socket 10, or the tracer 7 constitutes the scriber, reproducing this sketch on the support 8 with amplification. In other words, for the pur poses of this description it is immaterial whether the part 3 is considered the engraving point or the tracer, or whether the arm (3 is a scribing arm or tracer, the functions of these parts being interchangeable dependent upon whether the work to be done involves enlargement or reduction.

With this understanding it will be apparent that the instrument may be used. to reproduce microscopic drawings executed on the surface V which are to be reproduced on other similar surfaces by the double oper ation of first amplification or enlargment and then reduction, after the following manner: Assuming that the drawing which is to be reproduced is on the surface V. I substitute, as hereinbefore premised, a Stanhope lens for the engraving point 3, this lens having a slightly convex bearing surface provided with astandard or mark. The said mark is placed on the design and the latter is followed by moving the arm 6: the pencil G or, as faras that is concerned,

arranged in lift) an index which may be aflixed to the arm 6, will reproduce homographically on the surface 8 the design on V. Substituting for the surface V, the surfaces or surface that is now to be engraved, and replacing the diamond 3 in its proper place, the tracer following the reproduction ust made on the surface 8 will reproduce on the said surface V the homographic sketch and this sketch will be a strict reproduction of the original design which was on said surface. In like manner of substitution, the engraving point 3 may be replaced by a rotating or routing tool operated in any desired manner by a flexible driving element as is well known to those skilled in the art to which this invention relates. The depth of the engraving may be readily controlled. If it is to be uniform a simple stop piece (not shown) may be applied to the beam which will limit the depth of the cutting action. If the depth of the engraving must vary, as in the case of engraving cameos, metal stamps, etc., then a special arrangement must be provided.

The surface 8 may be of cylindrical or conical form if the sketch or drawing to be obtained is large, or if an extensive enlarge ment is desired it may be movable. It may be made up as follows: around a large cylindrical tube may be placed the paper bearing the sketch and the work surface V would likewise be placed upon a similar cylindrical surface, the size of which must be in proportion to the reduction desired. To obtain an enlargement of a microscopical sketch one may use as a work surface a cylinder the generatrices of which are inclined wiht respect to the pivot at an angle corresponding to the degree of amplification desired.

It is to be understood that the device may be constructed so that the pivot P will lie between the points 3 and 7. l/Vith such a construction there may be an interference in the reproducing although such interference may not amount to an inconvenience when reproducing on glass, because of its transparency. In any event, to prevent this interference it is only necessary to give to the surface 8 a symmetrical incline, i. e. a curvature the center of which would lie above the surface V, in a position symmetrical with that which it has on the accompanying drawing. which produces an inversion in the longitudinal direction as well as an inversion transversely. This arrangement is recommended where the instrument is to be affixed on a machine for engraving grad uated scales and for inscribing numerals, degree marks or the like associated therewith.

The instrument may be placed in front of the piece of work upon which the said scale is to be engraved, the said piece being movable or it may also be mounted upon the slide or carriage of the scale engraving machine, the object to be marked with divisions remaining still; in bothcases, one places thereon a small shoulder which is exactly rectilinear and is situated in the vertical plane of the said pivot post; the slide 7 bears againstthis shoulder to trace a line of the graduated scale; with this in view, one can carve a straight groove in the table; the scale numbers may be engraved at the same time; for example, before tracing the divisions, one may write above them the figures indicating the tens, (or the figure for the degrees in the case of angles) then after having traced the line of the division itself, one can write before the figure representing the units, or the decimals; the figures and lines indicating the divisions can thus be en graved at the same time by means of a continuous line so that the figures are materially attached to the corresponding line thus eliminating all errors when reading them.

As guidance in the engraving of figures, the operator can see under the lateral index on arm 6, and at the proper place, the guidefigure which he has but to follow to engrave the correct number; these guide figures are printed or engraved on two vignette disks,

one bearing the figures of the tens and the other the figures of the units; by a mechanism easy to build up and which varies according to the model of the dividing machine, these disks revolve when the carriage of the machine moves; for a movement of the carriage of one millimeter, for example, the vignette disk of the tens (or degrees) advances or turns back, one unit, whereas for movements of 0.2 mm. the units disk advances by two units (tenths of millimeters). One may therefore engrave at least ten figures side by side on a space of one millimeter and trace several hundreds of strokes or divisions in the space covered by one millimeter.

When the diamond point engraves working upwards, it engraves more deeply than when it works downhill; therefore, if one brings the piece V nearer to vertical, the engraved strokes obtained in making the slider 7 slide upwards on the table will be heavier than if the slider slides downward. Bearing this in mind, it is therefore possible to have divisions shown in very light engraving and have the figures corresponding showing light and heavy strokes, the heavy strokes being heavier than the division marks, which gives a very attractive appearance for the numbering.

Having thus described my invention, what I claim as new is l. in reproducing apparatus of the class described, the combination of a frame com prising a attern support and a work support angu arly related to the pattern sup ill) port, a pantographic device including abeam having a free swinging and sliding connection with the frame at one end, a tracer arm fixed to the beam to cooperate with the pat tern support, and a scribing member mounted on said beam in position to coact with the work support, the transformation of each point of the pattern in a transverse direction depending upon the ratio of the distances from the tracer arm and scribing: member to the connection to the frame, and the transformation of each point of the pattern in a longitudinal direction depending upon the inclination in the surface of the pattern support to the work surface at the particular point. 7

2. In reproducing apparatus of the class described, the combination with a pattern support having a convex surface and a work support, the surface of which is disposed at an angle to the convex surface, a pantographic device composed of a tracer coacting with the convex surface and a scriber coacting with the work surface, and means estab lishing a relation between said device and one of said surfaces and permitting free lateral and longitudinal movements of the tracer and scriber with relation to their re sp'ective cooperative surfaces.

3. In reproducing apparatus of the class described, the combination with a pattern support having a convex surface and a work neoases support the surface of which is disposed at an angle to the convex surface, a pantographic device composed of a tracer coacting with the convex surface and a scriber coacting with the work surface, and pin and slot connection between the device and the frame permitting free swinging and longitudinal movements of the device.

l. in reproducing apparatus of the class described, the combination with angularly related pattern and work surfaces of a pantographic device composed of a beam, a pivot member coacting with said beam and with respect to which it has sliding pivotal movement, a tracer arm adj ustably mounted on said beam, and a scriber carried by said beam and operated through the instrumentality of said beam and tracer.

In reproducing apparatus of the class described, the combination of a frame or support, a work support thereon, a pattern support thereon and angularly related to said work support and having a convex surface, a post adjustably mounted on said frame, a beam mounted on said post to have pivotal sliding: movement with relation thereto, and reproducing: means on said beam coacting with the respective work and pattern surfaces.

In testimony whereof I affix my signature.

CHAR-LES DEVE.

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