GB229189A - Improvements in protractors - Google Patents

Improvements in protractors

Info

Publication number
GB229189A
GB229189A GB1741724A GB1741724A GB229189A GB 229189 A GB229189 A GB 229189A GB 1741724 A GB1741724 A GB 1741724A GB 1741724 A GB1741724 A GB 1741724A GB 229189 A GB229189 A GB 229189A
Authority
GB
United Kingdom
Prior art keywords
disc
cylinder
arm
knob
marked
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
GB1741724A
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 GB1741724A priority Critical patent/GB229189A/en
Publication of GB229189A publication Critical patent/GB229189A/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
    • B43L13/001—Mathematical drawing instruments

Landscapes

  • Length-Measuring Instruments Using Mechanical Means (AREA)

Abstract

229,189. McLeod, J. D. July 21, 1924. Protractors.-The instrument consists of a base 1 having a semi-circular graduated part 2 and provided with a raised cylindrical bearing block 7 on which a disc 10 is mounted so as to be rotatable about an axis 12 pasing through the centre of the part 2. Also mounted on the axis 12 is an arm 13 provided with a bolt 15 passing through a slot 18 in the disc 10, to permit of adjustment of the arm over the disc. The arm is formed at its inner end with two recesses 23, 24, either of which can be passed over the pivot 12, so that either edge of the arm can be made to pass through the centre of the disc. The disc is formed with teeth 35 engaging a worm 34 on a shaft 30 connected by gears 36, 37 with a shaft 40 carrying a cylinder 42 and provided with a knob 41, so that by rotating the knob the disc 10 is turned, the gearing being such that one revolution of the cylinder turns the disc one degree. The ends of the cylinder are marked with graduations representing minutes of arc which are read aginst a stationary bar 45 above the cylinder. The surface of the cylinder is marked with lines arranged in the manner of a diagonal scale so as to indicate seconds of arc by their intersections with the graduated edge of the bar 45.
GB1741724A 1924-07-21 1924-07-21 Improvements in protractors Expired GB229189A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1741724A GB229189A (en) 1924-07-21 1924-07-21 Improvements in protractors

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1741724A GB229189A (en) 1924-07-21 1924-07-21 Improvements in protractors

Publications (1)

Publication Number Publication Date
GB229189A true GB229189A (en) 1925-02-19

Family

ID=10094826

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1741724A Expired GB229189A (en) 1924-07-21 1924-07-21 Improvements in protractors

Country Status (1)

Country Link
GB (1) GB229189A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109572286A (en) * 2018-12-17 2019-04-05 刘景典 A kind of mathematics drawing instruments

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109572286A (en) * 2018-12-17 2019-04-05 刘景典 A kind of mathematics drawing instruments
CN109572286B (en) * 2018-12-17 2020-07-03 刘景典 Mathematical drawing device

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