GB672563A - A device for facilitating the drawing of the normal at a point on a plane curve - Google Patents

A device for facilitating the drawing of the normal at a point on a plane curve

Info

Publication number
GB672563A
GB672563A GB676950A GB676950A GB672563A GB 672563 A GB672563 A GB 672563A GB 676950 A GB676950 A GB 676950A GB 676950 A GB676950 A GB 676950A GB 672563 A GB672563 A GB 672563A
Authority
GB
United Kingdom
Prior art keywords
interface
curve
blocks
normal
block
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB676950A
Inventor
James Dyson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Associated Electrical Industries Ltd
Original Assignee
Associated Electrical Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Associated Electrical Industries Ltd filed Critical Associated Electrical Industries Ltd
Priority to GB676950A priority Critical patent/GB672563A/en
Publication of GB672563A publication Critical patent/GB672563A/en
Expired legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43L—ARTICLES FOR WRITING OR DRAWING UPON; WRITING OR DRAWING AIDS; ACCESSORIES FOR WRITING OR DRAWING
    • B43L13/00—Drawing instruments, or writing or drawing appliances or accessories not otherwise provided for
    • B43L13/14—Devices for drawing in perspective
    • B43L13/16—Devices for drawing in perspective free-hand
    • B43L13/18—Devices for drawing in perspective free-hand having optical or projecting equipment

Landscapes

  • Lenses (AREA)
  • Optical Elements Other Than Lenses (AREA)

Abstract

672,563. Mathematical drawing-appliances. ASSOCIATED ELECTRICAL INDUSTRIES, Ltd. Jan. 4, 1951 [March 17, 1950], No. 6769/50. Class 97 (iii). A device for drawing the normal at a point 1 on a plane curve 2 comprises two blocks 5, 6 of transparent material cemented together with their top and bottom faces parallel to each other and normal to the interface which is so arranged for reflection that, when the device is placed on the curve with the interface normal to the plane of the curve, on looking down through the top face of one block, e.g. 5, at an angle slightly oblique to the interface, a portion 9 of the curve is seen through the bottom face of the block and a mirror image 10 of this portion is also seen formed by reflection at the interface. One block 6 may be longer than the other so that when the curve seen directly through the bottom face and its mirror image are continuous and without a kink the normal may be drawn by running a pencil point along the extended portions of the block 6.. The position and direction of the normal may be checked by observing a portion of the curve on the other side of the interface in a similar manner through the top surface of the block 6. To magnify any misalignment of the curve and its mirror image a magnifying lens with a convex cylindrical surface may be cemented to or formed integral with the top surface of one or each of the blocks, the cylinder axis being arranged at right angles to the interface in such a manner that when looking through the lens, lengths parallel to the interface are magnified whereas lengths perpendicular to the interface are unchanged. To obtain reflection at the interface one of the blocks may be silvered or aluminized or the like on its surface adjacent the interface. Alternatively the adjacent surfaces at the interface may be cemented together only in part so as to leave an air film between the two blocks or the blocks may be cemented together by means of a material, such as that known by the Trade Name " H.T. Cement," which has a refractive index sufficiently lower than that of the material of the blocks to allow total reflection to take place.
GB676950A 1950-03-17 1950-03-17 A device for facilitating the drawing of the normal at a point on a plane curve Expired GB672563A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB676950A GB672563A (en) 1950-03-17 1950-03-17 A device for facilitating the drawing of the normal at a point on a plane curve

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB676950A GB672563A (en) 1950-03-17 1950-03-17 A device for facilitating the drawing of the normal at a point on a plane curve

Publications (1)

Publication Number Publication Date
GB672563A true GB672563A (en) 1952-05-21

Family

ID=9820418

Family Applications (1)

Application Number Title Priority Date Filing Date
GB676950A Expired GB672563A (en) 1950-03-17 1950-03-17 A device for facilitating the drawing of the normal at a point on a plane curve

Country Status (1)

Country Link
GB (1) GB672563A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3006237A (en) * 1959-09-11 1961-10-31 Robert B King Optical device for viewing and generating curved lines

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3006237A (en) * 1959-09-11 1961-10-31 Robert B King Optical device for viewing and generating curved lines

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