GB1494997A - Drawing instrument - Google Patents

Drawing instrument

Info

Publication number
GB1494997A
GB1494997A GB3773973A GB3773973A GB1494997A GB 1494997 A GB1494997 A GB 1494997A GB 3773973 A GB3773973 A GB 3773973A GB 3773973 A GB3773973 A GB 3773973A GB 1494997 A GB1494997 A GB 1494997A
Authority
GB
United Kingdom
Prior art keywords
pivot
protractor
line
observer
constant
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
GB3773973A
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to GB3773973A priority Critical patent/GB1494997A/en
Publication of GB1494997A publication Critical patent/GB1494997A/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
    • B43L13/20—Curve rulers or templets
    • 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
    • B43L13/141—Two-dimensional devices
    • B43L13/144—Two-dimensional devices including protractors

Landscapes

  • Length-Measuring Instruments Using Mechanical Means (AREA)

Abstract

1494997 Drawing instrument D L STEWART 6 Nov 1974 [9 Aug 1973] 37739/73 Heading G1X [Also in Division B6] A drawing instrument comprises a pivot-mounted protractor integral with a centrally-aligned straight edge 10, having marked along it a scale the gradations of which are marked with identifying numerals bearing a R/X relation to the distance X of the gradation from the pivot. Preferably the protractor is marked with the secant of the angle between a line passing through the pivot and a protractor gradation and the extension of the straight edge, multiplied by a constant. The instrument is used to prepare perspective drawings from plans or maps. The pivot is placed over both an "observer" point O on a plan or map F and a corresponding "observer" point on the drawing, which has an "observer's" line at sight OC and a "horizon" line at right angles. The distance OC, the constant of the straight edge scale and the constant of the protractor scale are chosen to facilitate calculation of the vertical distance Y by which a point on the perspective drawing must be raised or dropped from the horizon line.
GB3773973A 1974-11-06 1974-11-06 Drawing instrument Expired GB1494997A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB3773973A GB1494997A (en) 1974-11-06 1974-11-06 Drawing instrument

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3773973A GB1494997A (en) 1974-11-06 1974-11-06 Drawing instrument

Publications (1)

Publication Number Publication Date
GB1494997A true GB1494997A (en) 1977-12-14

Family

ID=10398695

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3773973A Expired GB1494997A (en) 1974-11-06 1974-11-06 Drawing instrument

Country Status (1)

Country Link
GB (1) GB1494997A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2193929A (en) * 1986-08-18 1988-02-24 Wong Siu Bun Ruler

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2193929A (en) * 1986-08-18 1988-02-24 Wong Siu Bun Ruler
GB2193929B (en) * 1986-08-18 1990-10-17 Wong Siu Bun Ruler

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee