US2551082A - Drafting instrument - Google Patents

Drafting instrument Download PDF

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Publication number
US2551082A
US2551082A US178845A US17884550A US2551082A US 2551082 A US2551082 A US 2551082A US 178845 A US178845 A US 178845A US 17884550 A US17884550 A US 17884550A US 2551082 A US2551082 A US 2551082A
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US
United States
Prior art keywords
spring
head
drafting
block
instrument
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 - Lifetime
Application number
US178845A
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English (en)
Inventor
Anderegg Hermann
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.)
Cellophane SA France
Original Assignee
Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US2551082A publication Critical patent/US2551082A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • B43L13/02—Draughting machines or drawing devices for keeping parallelism
    • B43L13/04—Guides for rulers
    • B43L13/06—Guides for rulers with pivoted guide rods

Definitions

  • This invention relates to drafting instruments and more particularly to ruling devices mounted for parallel motion over the surface of the drawing board.
  • Drafting instruments of this character generally include a forearm supporting the head of the instrument, which is fitted with the right-angled rules, linked to another arm which in turn swings around fan anchoring means attached to the drawing board.
  • K y l v When the drawing boardis inclined, the as- Asembly described above tends to fall of its own weight towardsY the, foot ofthe board. It is therefore desirable to balance drafting instruments intended for. Work at a ⁇ certain inclination in such a manner that the draftsman can, without appreciable effort, displace the head over the entire surface of the board, and that this head will remain at a point where it has been placed without tending to shift when re-released.
  • the present invention accomplishes this purpose in a simple and improved manner.
  • FIG. 1 is a plan view of a drafting instrument embodying the present invention.
  • This device is shown for purposes of illustration as applied to a parallelogram type instrument. However it is equally applicable to a band instrument.
  • a drawing board I is mounted on a suitable support and is adapted to be inclined in any position from horizontal to vertical.
  • An anchoring bracket 2 is attached to the board and carries parallelogram links t and ft which are pivoted to the bracket '2 at 5 and 5 respectively.
  • the other ends of the links 3 and 4 are pivoted at I and 3 respectively to a block 9 to which parallelogram links lil and II are pivoted.
  • a support i2 carrying the drafting head I3 is attached to the second parallelogram by means of links IG and II pivoted at III and I5 respectively.
  • the drafting head I3, which is rotatable about its axis, carries a set of rules I6 and I1 set at right angles in the usual manner.
  • the rod 28 is rnade ⁇ of elastically ⁇ deformable material, such as pianoV wire and is adapted to iiex in response to an excessive pull by the spring 24 which may occur in certain positions of the drafting head.
  • the spring 24 normally balances the pull of the drafting head.
  • the spring may exert more pull than that required to balance the head and tend to pull the head upwardly.
  • the piano wire 28 flexes in response to such pull and relieves the tension of the spring. This prevents instability of the head when the spring '24 is under such excessive tension although the rod 28 normally provides a xed path for the trolley 21.
  • This rod 28 is clamped to the bracket 2 by means of a screw 2B which xes its position once its curved portion has been properly oriented.
  • the trolley 21 When the parallelogram links 3 and f3 are inclined to the left or to the right of the vertical X-Y, the trolley 21 is automatically displaced to the left or to the right along the curve of the rod 28, in such a manner that the axis of the spring 24 is always directed along the normal to this curve. Thus, e. g. in the dotted position of the first parallelogram in the figure, the trolley 21 has moved to the position 21.
  • the tension of the spring represented by the vector OR, may be resolved into two components OM and ON.
  • the component OM applied to the block 9 is without effect, being directed towards the points 5 and 6, whereas the component ON applied to the block 9 counterbalances the eifect of the weight of the parallelogram links 3 and 4, the block 9, and the parts carried thereby.
  • the parallelogram links In and II and head I3 likewise tend to fall of their own weight.
  • the wire 20 exertsa force represented by the vector OR upon the point I5 and this may be resolved into its two components OM' and ON. The latter opposes the effect of gravity upon the head I3 and the parts carried thereby.
  • the spring may be fitted with a simple and known device with which it is possible, for a given inclination of the board, to obtain a suitable tension relative to that inclination.
  • the device described has a single spring for balancing the two arms.
  • a drawing board having an instrument mounted on a member to swing with a parallel motion over the surface of the board, and a spring attached at one end to said member and adapted to exert a pull for balancing the weight of said member, an anchor for the other end of said spring and a curved exible wire track supporting said anchor for movement along a normally xed path in response to the swinging of saidmember, said path being selected to cause the spring to oppose the effect of gravity in all positions of said member, said wire being deformable in response to an excessive pull of said spring caused by said member when in certain positions.
  • a pair of parallelogram links pivoted to swing thereover and carrying a block
  • a second pair of parallelogram links pivoted to said block and carrying a drafting head
  • a pulley on said block a flexible tension member attached to said head and extending around said pulley, said tension member being adapted to exert a pull for balancing the weight of said head
  • a trolley attached to the free end of said tension member
  • a flexible wire supporting said trolley for movement along a normally fixed path in response to the swinging of said block, said path being selected to cause said tension member to oppose the effect of gravity in all positions of said head and being deformable in response to an excessive pull of said tension member caused by said head when in certain positions.

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  • Tension Adjustment In Filamentary Materials (AREA)
  • Manipulator (AREA)
US178845A 1947-06-02 1950-08-11 Drafting instrument Expired - Lifetime US2551082A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR2551082X 1947-06-02

Publications (1)

Publication Number Publication Date
US2551082A true US2551082A (en) 1951-05-01

Family

ID=9686401

Family Applications (1)

Application Number Title Priority Date Filing Date
US178845A Expired - Lifetime US2551082A (en) 1947-06-02 1950-08-11 Drafting instrument

Country Status (5)

Country Link
US (1) US2551082A (enrdf_load_html_response)
BE (1) BE490085A (enrdf_load_html_response)
CH (1) CH279325A (enrdf_load_html_response)
DE (1) DE804414C (enrdf_load_html_response)
NL (1) NL72784C (enrdf_load_html_response)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1014884B (de) * 1956-08-20 1957-08-29 Janez Peklenik Dipl Ing Zeichenvorrichtung mit Parallelfuehrung
DE1101218B (de) * 1960-05-05 1961-03-02 Franz Kuhlmann K G Praez Smech Gewichtsausgleich eines an einer Parallelogrammfuehrung aufgehaengten Zeichenkopfes einer Zeichenvorrichtung

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB175183A (en) * 1921-02-01 1922-02-16 William Mavitia Improvements in drafting machines
DE551532C (de) * 1928-12-15 1932-06-02 Philips Nv Elektrische Gluehkathodenentladungsroehre
GB411243A (en) * 1933-02-28 1934-06-07 Viktor Graf Improvements in or relating to draughting machines of the parallelogram type

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB175183A (en) * 1921-02-01 1922-02-16 William Mavitia Improvements in drafting machines
DE551532C (de) * 1928-12-15 1932-06-02 Philips Nv Elektrische Gluehkathodenentladungsroehre
GB411243A (en) * 1933-02-28 1934-06-07 Viktor Graf Improvements in or relating to draughting machines of the parallelogram type

Also Published As

Publication number Publication date
CH279325A (fr) 1951-11-30
NL72784C (enrdf_load_html_response)
DE804414C (de) 1951-04-23
BE490085A (enrdf_load_html_response)

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