US3137944A - Copying mechanisms - Google Patents

Description

Jlme 1964 HANS-GERHARD FUCHS 3,137,944

COPYING MECHANISMS Filed March 9, 1961 3 Sheets-Sheet 1 Jnvenfar: H-G. Ecs

June 23, 1964 HANS'GERHARD FUCHS 3,137,944

COPYING MECHANISMS Filed March 9, 1961 3 Sheets-Sheet 2 Fly. 3

Jnvenfor: H 5&5

$MM JW June 23, 1964 HANS-GERHARD FUCHS 3,137,944

COPYING MECHANISMS 5 Sheets-Sheet 3 Filed March 9, 1961 United States Patent Ofi 3,137,944 Patented June 23, 1964 3,137,944 COPYING MECHANISMS Hans-Gerhard Fuchs, Wilhelmshaven, Germany, assignor to Franz Kuhlmann K.G., Wilhelmshaven, Germany Filed Mar. 9, 1961, Ser. No. 94,583 Claims priority, application Germany Mar. 14, 1960 6 Claims. (Cl. 33-25) This invention relates to a pantograph in which the movement of a scanning or guiding pin is transmitted, in an adjustable size relationship, to an inscribing instrument or to an engraving, milling or copying spindle through the intermediary of pivotally interconnected transmission members.

Most of the pantographs known hitherto are based on the diagraph principle and are formed as parallelogram pantographs. An essential prerequisite for the satisfactory operation of parallelogram pantographs of this kind is that the point of suspension, the engraving spindle and the scanning pin must all lie accurately on one and the same straight line. In order to achieve this accurate adjustment during manufacture, slides are usually employed which are adjusted according to Vernier scales. High demands are therefore made on the accuracy of the slide surfaces, and this leads to comparatively high costs of manufacture.

In three-dimensional copying, a further disadvantage of the simple parallelogram pantographs is that unless additional expedients are employed it is not possible to obtain a transmission ratio of 1: 1, since the working region of the scanning pin and of the engraving or copying spindle would then necessarily coincide. In practice this is not possible. On the other hand, if a special arrangement is used in which the suspension bearing is between the engraving or copying spindle and the scanning or guiding pin and which permits an adjustment to 1:1 during two-dimensional engraving in a plane, then these pantographs can also be used for three-dimensional contour milling without any additional modifications. For the purpose of obtaining any required transmission ratios (including 1:1) in a simple manner, a copying and engraving machine has been proposed which comprises a two-armed support lever rockable about a pivot and slidable relatively to the pivot and carrying two rotary discs one on each arm, which are interconnected by a driving belt. In this known construction the axes of the discs are parallel to the axis of the rocking pivot; moreover, the centres of the discs and of the rocking pivot lie all on one straight line. The scanning pin and the tool are radially adjustably arranged each on a respective one of the discs in such a manner that the axes of the scanning pin, the tool and the pivot lie all on one straight line.

This known belt pantograph certainly makes it possible to obtain any required transmission ratios (including the ratio 1:1) without calling for great constructional expense for this purpose; this construction, however, is pref- 'erably restricted to two-dimensional operations.

For the purpose of obtaining reductions, enlargements and products in the ratio of 1:1 both in a plane and in three dimensions, WithOllthaving the model and workpiece transposed relatively to one another, an engraving and copying machine has been proposed in which a beam guided so as to remain parallel to itself is moved by means of a diagraph and the tool or the guide pin or both can be inserted into the beam. In this known construction, two links arranged in a parallelogram carry a beam on which a longitudinally displaceable carriage slides and carries the tool support or the guide pin or both. In order to permit operations in three dimensions, the diagraph is rockable about an axis parallel to the plane of the model and workpiece, and the links carrying the parallel-guided beam are mounted on a carriage movable perpendicularly to this plane.

-This known construction based on the diagraph principle is, however, comparatively complicated from the point of view of manufacturing technology because of the large number of pivot points required, and also requires a considerable amount of space. Particular difliculties also arise from the fact that the slides of theseparallelogram pantographs have to be accurately adjusted as mentioned at the outset.

The invention is therefore based on the problem of avoiding the disadvantages of the known construction and of so forming a pantograph of the kind mentioned at the outset that in spite of simplicity of mechanical structure it is possible to operate with a transmission ratio of 1:1 without thus causing even partial overlap of the working regions of the scanning pin and of the engraving, milling or copyingspindle. Moreover, the new pantograph is to be so constructed that it can also be used for threedimensional operations Without great additional expense.

This problem is solved, according to the invention, by a construction in which the scanning pin and the milling spindle of a two-circle pantograph are each independently mounted on a respective outer arm pivoted to a respective rockably mounted inner arm, and the ratio between the lengths of the outer and inner arms is the same for the scanning pin as for the milling spindle, and the two inner arms and the two outer arms are in each case interconnected by connecting members permitting pivotal movements ofthe inner and of the outer arms, which movements are independent of one another.

In contradistinction to the known parallelogram pantographs, in the two circle pantographs constructed in accordance with the present invention the scanning pin and the milling spindle are always at an accurately predetermined distance from one another; they do not come into a crossed'position, nor does even partial overlappingof the regions covered by the scanning pin and by the milling spindle occur during operation with a transmission ratio of 1:1. Instead, for all adjustments the region covered remains in an advantageous position over the work table and the model or template table respectively thus permitting particularly easy and accurate work.

The suspension of the scanning pin and the engraving or milling spindle on two separate bearings in accordance with the invention has the further advantage that the bearing for the milling side can be made particularly stable, whereas the bearing for the scanning pin can be made lighter .and therefore more cheaply.

A further particular advantage of the two-circle pantograph constructed in accordance with the present invention is thatthis pantograph can also be used for threedimensional work without great additional expense. For this purpose it is only necessary for the fulcra of the two inner arms to be formed as universal joints permitting pivotalmovement about two axes at right angles to one another. The two-circle pantograph constructed in accordance with the present invention is .thus distinguished by a substantially simpler construction as compared with known pantographs permitting three-dimensional opera tion with a transmission ratio of 1:1.

In one embodiment of the two-circle pantograph of the present invention that has been found to be advantageous, the effectivelength of the outer arm carrying the milling spindle, which length extends from the milling spindle to the pivot bearing of this arm, and the eiiective length of the associated inner arm, which length extends from the pivot bearing of the outer arm to the bearing point of the inner arm, are variable proportionally to one another for the purpose of adjusting the transmission ratio of the pantograph.

In a two-circle pantograph in which the fulcra of the two inner arms are interconnected by a rigid connecting rod and the transmission of the movement from the inner and outer arm of the scanning pin to the inner and outer arm of the milling spindle is effected by two transmission members guided parallel to one another and acting pivotally on the arms, a particularly advantageous solution from a constructional point of view is obtained if the point of action on the inner arm of the milling spindle is displaceable along this arm together with the fulcrum of this arm.

That end of the transmission member between the two outer arms which is adjacent to the scanning pin side preferably acts freely slidably on a rod which forms a parallelogram in conjunction with an arm parallel to the rod, a part of the outer arm and a further arm.

During operation with a transmission ratio of 1:1, in accordance with a further feature of the invention a substantial increase in the rigidity of the pantograph system can be obtained by interconnecting the free ends of the two outer arms by means of a rigid intermediate rod. This intermediate rod is then removed for the purpose of operation with any other transmission ratio.

These and other details of the invention will appear from the following description of an embodiment of the invention chosen by way of example and illustrated in the accompanying drawings, in which:

FIGURE 1 is a diagrammatic view, in elevation, of a two-circle pantograph constructed in accordance with the invention, adjusted to a transmission ratio other than 1:1,

FIGURE 2 is a diagrammatic view, in elevation, of this pantograph system adjusted to 1:1, and

FIGURE 3 diagrammatically illustrates a two-circle pantograph constructed in accordance with the invention, together with a template table and a Work table.

The two-circle pantograph constructed in accordance with the invention contains a scanning or guiding pin 1, an engraving, copying or milling spindle 2 and a lever linkage by which these two members are interconnected and guided with a variable transmission ratio.

The scanning pin 1 is mounted at the end of an outer arm 3 rockably connected to an inner arm 5 at a pivot point 4. The inner arm is also rockably mounted at a pivot point 6.

The milling spindle 2 is adjustably arranged on an outer arm 7 pivotally connected to an inner arm 9 at a point 8. The inner arm 9 is also rockable about a pivot point 10.

The end of the outer arm of the scanning pin 1 remote from the scanning pin 1 is pivotally connected to an arm 11 which forms a parallel guide in conjunction with an arm 12 mounted at the pivot point 6.

A connecting rod 13 acts slidably on the arm 11, and the other end of the connecting rod is pivotally connected to the outer arm 7 of the milling spindle 2.

The inner arm 5 of the scanning pin 1 is linked to the inner arm 9 of the milling spindle 2 by way of a transmission arm 14. The transmission arm 14 acts on the inner arm 9 at a pivot point 15; this point together with the fulcrum 10 of the inner arm 9 can be displaced along the arm 9 by means of a slide 16. This displacement is made possible by the fact that the sliding guide 17 permits the transmission arm 13 to slide along the arm 11 at the same time. The fulcra 6 and 10 of the inner arms 5 and 9 are rigidly interconnected by a connecting rod 18.

The dimensions of the two-circle pantograph are preferably made such that the effective length of the outer arm 3, which length extends from the scanning pin 1 to the pivot point 4, is exactly the same as the effective length of the inner arm 5, which length extends from the pivot point 4 to the fulcrum 6. The arms 3 and 5 can thus describe circles of equal diameter.

Likewise, the effective length of the outer arm 7 of the milling spindle 2, which length extends from the milling spindle 2 to the pivot point 8, is equal to the clfective length of the inner arm 9, which length extends from the pivot point 8 to the fulcrum 10. The movement of the milling spindle also can thus be ascribed to two basic circles shown in broken lines in the drawing.

The arms 5 and 9 may alternatively be shorter or longer than the arms 3 and 7. In each case, an equalratio transmission must take place.

The manner of operation of the two-circle pantograph constructed in accordance with the invention will be immediately apparent from the foregoing description and from the drawings.

If the scanning pin 1 makes a given movement resulting in a rocking movement of the outer arm 3 about the fulcrum 4 and a rocking movement of the inner arm 5 about the fulcrum 6, then the outer arm 7 and the inner arm 9 of the milling spindle 2 are correspondingly pivotally moved through the intermediary of the connecting rod 13 and the transmission arm 14 respectively. The articulated parallelogram formed by the arms 11 and 12 and by the adjacent parts of the arms 3 and 5, ensures satisfactory parallel guiding of the transmission arms 13 and 14 during these movements.

It is clear from the drawings that the transmission ratio can be changed as required, by changing the effective length of the outer arm 7 and of the inner arm 9. In connection with this it is of particular importance that the length of the transmission arms 13 and 14 should be suitably large so that this change cannot result in any overlapping of the working regions of the scanning pin 1 and of the milling spindle 2. Instead, the working regions of these two members remain on the model table and work table respectively.

FIGURE 2 shows the two-circle pantograph constructed in accordance with the invention, with a transmission ratio of 1:1. In this case the slide 16 is at the end of the inner arm 9 of the milling spindle 2; the transmission arm 13 acts on the pivot point 19 between the outer arm 3 and the rod 11. The slide 17 coincides with the pivot point 19.

In order to increase the rigidity of the pantograph system, when the transmission ratio is 1:1 the two outer arms 3 and 7 are interconnected by a rigid removable connecting rod 20.

If the two-circle pantograph constructed in accordance with the invention is also to be used for three-dimensional operations, then the fulcra 6 and 10 of the two inner arms 5 and 9 are formed as universal joints permitting rocking movement in two directions at right angles to one another, that is to say, in the plane of the drawing and at right angles to the plane of the drawing. The construction is preferably made such that in three dimensional milling the whole system can be additionally rocked about the longitudinal axis of the connecting rod 18 or axes parallel to this axis.

In the two-circle pantograph constructed in accordance with the invention it is possible, as in the known pantograph systems for three-dimensional operation, to interchange the scanning pin and the engraving pin together with its driving means, so that the machine which previously supplied a reduced version of the model in accordance with a required transmission ratio, can now make a corresponding enlargement.

FIGURE 3 diagrammatically illustrates a two-circle pantograph constructed in accordance with the invention, together With a template table and a work table.

The pantograph system is mounted at a pivot point 31 on a support pedestal 30 by means of a connecting arm 18. The pantograph support pedestal 30 is rigidly connected to a column 25.

The column 25 is provided with a transverse beam 34 used for transverse displacement of brackets 32 and 33.

The work table bracket 32 can be laterally adjusted in a horizontal direction by means of a hand wheel 24, and

the template table bracket 33 can be similarly adjusted by means of hand wheel 23.

The template table support 22 can be moved in a vertical direction on the template table bracket 33 by means of a hand wheel 26. On its top side this support carries a rockably mounted template table 28.

Similarly, the work table support 21 can be moved vertically on the work table bracket 32 by means of a hand wheel 35. A handle 27 is also provided to enable the work table 29, which is provided on the work table support 21, to be displaced forwards or backwards in a horizontal direction.

The other reference numerals used for the pantograph system of FIGURE 3 are the same as in FIGURES 1 and 2 in FIGURE 3, the system is adjusted to the transmission ratio 1:1.

I claim:

1. In a three dimension pantograph having two points, one said point being used as a scanning point and the other said point being used as a copying point, a first inner arm and a second inner arm each pivoted at a fixed distance from each other on fixed pivots, first parallelogram link means connecting said inner arms to hold said inner arms parallel to each other at all times as they move on their pivots, the first of said inner arms being adjustable in length and the second of said arms being fixed in length, a first outer arm pivoted to the end of said first inner arm, and a second outer arm pivoted to the end of said second inner arm, parallelogram linkage means including said second inner arm and said second outer arm providing a link at all times parallel to said second inner arm, means carrying a pivot adjustable along said link parallel to said second inner arm, a link pivotally connected to said first outer arm and to said means carrying a pivot whereby said first and second outer arms may be held in parallelism at all times, means on said first outer arm adjustable therealong adapted to carry one of said points, the other of said points being carried by said second outer arm, the adjustability of the length of said first inner arm, and the adjustability of the position of the means adapted to carry one of the points on said first outer arm providing for proportioning the effective lengths of said first inner and outer arms with respect to said second inner and outer arms to provide adjustable pantograph motion between said two points, said first and second inner arms and said first and second outer arms lying at all times in a generally common plane, the said inner arms being pivoted at said fixed pivots for angular movement normal to a line connecting said fixed pivots.

2. The pantograph as claimed in claim 1, comprising an intermediate rod rigidly connecting the free ends of the two outer arms in the case of a transmission ratio of 1:1.

3. Pantograph comprising a scanning pin and a copying spindle, means by which said pin and spindle are connected with one another in an adjustable size relationship, said means including first and second outer arms, each having a rearward extension, one of said outer arms carrying the scanning pin and the other the copying spindle, first and second inner arms, each having an outer end and a rearward extension, means rockably mounting each of said outer arms on the outer end of respective ones of said inner arms, fixed pivot means associated with each of said rearward extensions of said inner arms, means rigidly connecting said fixed pivot means with respect to each other, a rigid connecting member connecting together said rearward extensions of said inner arms, said rigid connecting member and said means for rigidly connecting forming a parallelogram for guiding the inner arms in an angularly parallel manner, the inner arm on the copying spindle side being adjustable in length extending from said parallelogram, the rearward extensions of the outer arms being connected with one another through the intermediary of parallel guided connecting members in the form of an angularly parallel guiding parallelogram, which is formed by the inner arm on the scanning pin side, the rearward extension of the associated outer arm and two parallel extending supplementary rods, a rod connecting the rearward extension of the outer arm carrying the copying spindle to the supplementary rod extending parallel to the inner arm on the scanning pin side, and means providing for adjustment along the supplementary rod.

4. Pantograph comprising a scanning pin and a copying spindle which are pivotally connected with one another in an adjustable size relationship, parallel guided transmission members displaceable at their free ends along base circles, two outer arms, the scanning pin and the copying spindle being each independently mounted on one of said outer arms, each said outer arm including a rearward extension, two inner arms, first pivot means for pivoting each said inner arm on a respective outer arm, said inner arms being also provided with rearward extensions, second pivot means associated with said rearward extensions of said inner arms, a rigid connecting member connecting the rearward extensions of said inner arms, a rigid connection supporting the said second pivot means of the inner arms, said rigid connecting member and said rigid connection forming a parallelogram linkage guiding the inner arms in an angularly parallel manner, the said first pivot means of the two inner arms being formed as universal joints so that a pivotal movement about two axes at right angles to one another is provided, one of the axes being parallel with the connecting member for the two inner arms, parallel guided connecting members connecting the rearward extensions of said outer arms including a parallelogram formed by the inner arm of the scanning pin, the rearward extension of the associated outer arm and two parallel extending supplementary links, and a link connecting the rearward extension of the outer arm carrying the copying spindle to the supplementary rod extending parallel to the inner arm on the scanning pin side and adjustably pivoted on the supplementary rod.

5. Pantograph comprising a scanning pin and a copying spindle which are pivotally connected with one another in an adjustable size relationship through the intermediary of parallel guided transmission members displaceable at their free ends along base circles, said transmission members including two outer arms, a scanning pin and a copying spindle being each independently mounted on one of said outer arms, inner arms pivoted to said outer arms and having rearward extensions, said inner arms being pivotally connected to a fixed base, a rigid connecting member connecting said rearward extensions of said inner arms to form with the fixed base connection of the pivots of the inner arms a parallelogram linkage guiding said inner arms in an angularly parallel manner, said parallelogram linkage being freely displaceable along the inner arm on the copying spindle side to provide for adjustment of the effective length of said inner arm, parallel guided connecting members connecting the rearward extensions of the outer arms with one another, said parallel guided connecting members being designed in the form of an angularly parallel guiding parallelogram linkage which is formed by the inner arm placed on the scanning pin side, the rearward extension of the associated outer arm and two parallel extending supplementary rods, the rearward extension of the outer arm carrying the copying spindle being connected by a rod to the supplementary rod extending parallel to the inner arm on the scanning pin side, and an adjustable pivot adjustably displaceable on the supplementary rod in such a manner that the adjustable length relationships of the inner and outer arm on the scanning pin side and the copying spindle side are the same in each case.

6. In a pantograph of the type having a scanning pin and a copying spindle connected together by a lever and linkage system to give adjustable proportional movement between said scanning point and said copying spindle, a scanning point outer arm having a scanning point, a scanning point inner arm, said scanning point inner and outer arms being pivoted at respective fixed points, saidfixed points being at a fixed distance from each other and also pivoted to said scanning point outer arm, said scanning point being mounted on said scanning point outer arm at a distance from said pivot between said scanning point outer and inner arms identical to the distance between said pivot between said scanning point arms and said fixed point, a first parallelogram link means including said scanning point outer and inner arms and including a link parallel at all times to said scanning point inner arm, a copying spindle outer arm, and a copying spindle inner arm pivoted to each other, a fixed pivot for said copying spindle inner arm, said copying spindle inner arm being pivoted at said fixed pivot and adjustable with respect thereto to adjust the distance between said fixed pivot and the pivot between said copying spindle inner and outer arms, a copying spindle adjustably mounted on said copying spindle outer arm, a second parallelogram link means connecting said copying spindle inner arm and said scanning point inner arm to hold said inner arms parallel at alltimes, and a link pivoted to said copying spindle outer arm at one end, and pivoted to a means at the other end adapted to be adjusted along the length of the link of said first parallelogram link means that is parallel at all times to said scanning point inner arm, and means by which said pantograph device may be pivoted about an axis through the said fixed points at which said inner arms are pivoted.

References Cited in the file of this patent UNITED STATES PATENTS 370,939 Frankenberg Oct. 4, 1887 725,654 Barr Apr. 21, 1903 1,030,807 Frew June 25, 1912 1,347,695 Gillespie July 27, 1920 1,884,960 Anderson Oct. 25, 1932 FOREIGN PATENTS 219,002 Australia Nov. 27, 1958

Claims (1)

1. IN A THREE DIMENSION PANTOGRAPH HAVING TWO POINTS, ONE SAID POINT BEING USED AS A SCANNING POINT AND THE OTHER SAID POINT BEING USED AS A COPYING POINT, A FIRST INNER ARM AND A SECOND INNER ARM EACH PIVOTED AT A FIXED DISTANCE FROM EACH OTHER ON FIXED PIVOTS, FIRST PARALLELOGRAM LINK MEANS CONNECTING SAID INNER ARMS TO HOLD SAID INNER ARMS PARALLEL TO EACH OTHER AT ALL TIMES AS THEY MOVE ON THEIR PIVOTS, THE FIRST OF SAID INNER ARMS BEING ADJUSTABLE IN LENGTH AND THE SECOND OF SAID ARMS BEING FIXED IN LENGTH, A FIRST OUTER ARM PIVOTED TO THE END OF SAID FIRST INNER ARM, AND A SECOND OUTER ARM PIVOTED TO THE END OF SAID SECOND INNER ARM, PARALLELOGRAM LINKAGE MEANS INCLUDING SAID SECOND INNER ARM AND SAID SECOND OUTER ARM PROVIDING A LINK AT ALL TIMES PARALLEL TO SAID SECOND INNER ARM, MEANS CARRYING A PIVOT ADJUSTABLE ALONG SAID LINK PARALLEL TO SAID SECOND INNER ARM, A LINK PIVOTALLY CONNECTED TO SAID FIRST OUTER ARM AND TO SAID MEANS CARRYING

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