US2669025A - Apparatus for producing perspective drawings - Google Patents

Description

Feb. 16, 1954 H sm 2,669,025

APPARATUS FOR PRODUCING PERSPECTIVE DRAWINGS Filed March 22. 1949 Patented Feb. 16, 1954 UNITED sures APPARATUS FOR PRODUCING PERSPECTIVE DRAWINGS H o Erik G. Hysing, Stockholm, Sweden, assignor to Aktiebolaget 'Kontrollinstrument, Stockholm Sweden, a corporation of Sweden Application March 22, 1949, Serial No. s2,752

7 Claims.

known type of apparatus for producing perspective drawings contains two rulers, mutually turnably connected, which are each separately slidably arranged in a fixture which is in its turn turnably mounted about a fixed point. In; this way there is thus formed a triangle, the sides of which are the two rulers and the connection line between the two fixed points, respectively. In the connection point between the two rulers, finally there is turnably mounted a third ruler which is preferably intended for the vertical' position. v

I The two first mentioned rulers are arranged t'obe pushed into orpulled out of rollers, provided in immediate vicinity of the fixed points.

In the hitherto known perspective drawing apparatus of the above mentioned kind, one has had no freedom in choosing the perspective. The pe'rspective'is determined by two distances, via. the socalled D-distance or D-value and the so called H-distance or H-value. The D-value is the distance from the midpoint of the horizontal line to the vanishing point on the one side of the horizontal line, or in other'words, half the perspectively reproduced horizontal line, whereas the H-value is represented by the distance from theobservation point to the midpoint of the horizontal line. As a measure of the perspective it is customary to state the tangent of the per'spectiveangle orin other words, the I-I-value, divided by" the D-value. It is now obvious that in a perspective ruler of the above mentioned kind, one canput the H-value in any chosen way and, consequently, obtain any desired value of the perspective angle. Any separate value of the perspective angle, however, will be directly related to a predetermined'scale, because the D- value in the hitherto known perspective rulers hasbeen fixed and could not be changed. The advantage of a perspective ruler of the kind here described, however is, that one can place perspectively graded scales along the rulers in the apparatus, but even these scales must obviously be fixed,,one for each chosen perspective angle. Therefore, the disadvantage will occur that one cannot by the same perspective drawing apparatus' draw a large object and a small object,

tion with the attached drawings in which Fig. 1 shows an apparatus for producing perspective drawings according to the invention in total view,

and Figs. 2, 3, 4, and 5 show parts of the arrangement according to Fig. 1.

It is assumed that the arrangement according to Fig. 1 is clamped on a drawing board it, on the back side of which there are according to the invention arrangements for slidably fixing bars I I and I2, so that they extend exactly in line with each other. The bars areprovided, at their outer ends, with a perpendicular pivot or shaft 50, see Fig. 3, on which rollers l3, M are mounted. The rollers l3, I4 contain, in a manner known from so called steel tape measures, transversally bent steel tapes or metal tapes l5, 16, which can be rolled up on the rollers and which are turnably and the third side of the triangle being disposed at a predetermined angle, the so called perspective angle. In such apparatus for producing perspective drawings which are intended for use with different perspective angles, the triangular template 2| should preferably be interchange-- able, which may, for instance, the efiected by loosening the grip l1, changing the template for another one and tightening again the grip in place.

In connection with the change of the triangular member, as a rule, the scales of the perspective rulers I 9, 20 must also be changed. In order that this shall be possible, the scales are put in place by inserting their ends under a pair of hook forming means 22, 23, and 24, 25, respectively.

The scale of the ruler I8 is linearly marked, whereas the scales [9 and 20 are mutually equal although inverted. They may be calculated or they may be constructed in such a way that they give direct perspective length measure in the chosen perspective, represented by the scales l9 Figs. 2, 3, 4, and 5 show details of the invention, and it is assumed that the function of these figurges will be apparent from the above description.

Thus, Fig. 2 shows the grip H, the parts of the rulers l5, I6, and I8, connected thereto, and the locking members 26 and 21, the latter ones having the form of excentric plates with a wing, intended to contact the edge 49 of the lower part of the grip under a pressure, that may be controlled by turning the excentric plates by means of the wing.

Fig. 3 shows a roller I4 from the side, the pivot pin 50, by means of which the roller is guided in the bar l2, and the locking screw 28, by means of which the roller I4 is pressed together in such a way that the ruler 16 which is formed by a transversally bent steel band, cannot move in relation to the roller I4.

Fig. 4 shows the hooks 22, 23 on the ruler l5 5 for fixing the scale bar [9 in place.

Finally, Fig. 5 shows the fixture 5|, which is intended to be fixed on the back side of the drawing board In by means of the screws 52, 53, 54, and 55. Two square section pipes or guides 56 and 51, respectively, are secured to the fixture, so that the bars H and 12 are movably guided within them. Two lock nuts 58 and 59 are provided for fixing the bars I l and 12 in correct po'- sition. In this way, it is possible in every case to adapt the D-value according to the present need, the usability of the perspective drawing apparatus thereby being increased to a very high degree.

The invention shall not be regarded as limited to the form of execution, shown in the drawing said tapes adjacent their point of intersection, a

linear scale pivotally secured to said tapes at their point of intersection and extending to one side thereof, a triangular template integral with said linear scale and extending from the opposite sides of the tapes, means for locking said rollers.

against rotation, and means for locking said tapes and said linear scale against relative pivotal movement whereby a perspective drawing may be accurately constructed to scale.

2. An apparatus as defined in claim 1 in which said tapes are formed of steel and are concaveconvex in cross section.

3. An apparatus as defined in claim 1 in which the means for locking said tapes and said linear scale against relative pivotal movement comprise pivotally mounted cams engaging the pivot means pivotally connecting said tapes and said linear scale having finger engaging extensions.

4. An apparatus as defined in claim 1 in which said tapes and said linear scale are pivotally connected by a hand engaging member whereby manipulation of said apparatus is facilitated.

5. Apparatus for producing perspective drawings comprising axially aligned bars adapted to be slidably mounted on the underside of a drawing board and extending from opposite sides thereof, a roller pivotally mounted on the extending end of each bar, an extensible and retractible tape received on each roller, said tapes being pivotally connected at their points of intersection, scales calibrated in accordance with the perspective to be drawn detachably secured to said tapes adjacent their point of intersection, a linear scale pivotally secured to said tapes at their point of intersection and extending to one side thereof. and a triangular template intergral with said linear scale and extending from the opposite side of said tapes whereby a perspective drawing may be accurately constructed to scale.

6. Apparatus for producing perspective drawings comprising axially aligned bars adapted to be slidably mounted on the underside of a drawing board and extending from opposite sides thereof, a roller pivotally mounted on the extending end of each bar, an extensible and retractible tape received on each roller, said tapes being pivotally connected at their point of intersection, scales calibrated in accordance with the perspective to be drawn detachably secured to said tapes adjacent their point of intersection, and a linear scale pivotally secured to said tapes at their point of intersection and extending to one side thereof whereby a perspective drawing may be accurately constructed to scale.

7. Apparatus for producing perspective drawings comprising a drawing board, axially aligned bars slidably mounted on the underside of said board and extending from opposite sides thereof, an extensible and retractible tape adjustably secured to the extending end of each bar, said tapes being pivotally connected at their point of intersection, scales calibrated in accordance with the perspective to be drawn detachably secured to said tapes adjacent their point of intersection, and a linear scale pivotally secured to said tapes at their point of intersection and extending to one side thereof whereby a perspective drawing may be accurately constructed to scale.

ERIK G. HYSING.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 535,717 McLean Mar. 12, 1895 577,472 White Feb. 23, 1897 1,657,301 De Postels Jan. 24, 1928 1,990,040 Launay Feb. 5, 1935 2,380,073 Robinson July 10, 1945 2,454,388 Hurst Nov. 23, 1948 FOREIGN PATENTS Number Country Date 19,824 Great Britain Dec. 4, 1890 360,730 Great Britain Nov. 12, 1931 591,691 Great Britain Aug. 26, 1947

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