US3672062A - Portable drafting device - Google Patents

Portable drafting device Download PDF

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Publication number
US3672062A
US3672062A US122406A US3672062DA US3672062A US 3672062 A US3672062 A US 3672062A US 122406 A US122406 A US 122406A US 3672062D A US3672062D A US 3672062DA US 3672062 A US3672062 A US 3672062A
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United States
Prior art keywords
roller
board
drafting
curvature
magnetized
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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
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US122406A
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English (en)
Inventor
Allister L Baker
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.)
Keuffel and Esser Co
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Keuffel and Esser Co
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Publication of US3672062A publication Critical patent/US3672062A/en
Assigned to CHASE MANHATTAN BANK, N.A. THE; A NATIONAL BANKING ASSOCIATION, BANK OF CALIFORNIA N.A. THE; A NATIONAL BANKING ASSOCIATION, CONTINENTAL ILLINOIS NATIONAL BANK & TRUST CO., OF CHICAGO, A NATIONAL BANKING ASSOCIATION, SECURITY NATIONAL BANK, A NATIONAL BANKING ASSOCIATION FOR ITSELF AND AS AGENT FOR CITIBANK, N.A. A NATIONAL BANKING ASSOCIATION, CHEMICAL BANK, A BANKING INSTITUTION OF reassignment CHASE MANHATTAN BANK, N.A. THE; A NATIONAL BANKING ASSOCIATION SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KEUFFEL & ESSER COMPANY A.N.J. CORP
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Expired - Lifetime legal-status Critical Current

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    • 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
    • B43L13/005—Portable combined drawing-aids including boards
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S33/00—Geometrical instruments
    • Y10S33/01—Magnetic

Definitions

  • ABSTRACT A lightweight drafting device comprises a ferrous board and a magnetized roller which acts as a paper holder and guide means for a drafting element.
  • the strong magnetic attraction between the board and roller ensure a fixed relation between the paper and drafting element, and maintains parallelism between drawn lines.
  • the device is readily transportable and is operable in any convenient attitude.
  • ATTORNEY BACKGROUND Drafting machines broadly preferred in the field of engineering drawing are generally of a type which provides vertical and horizontal straightedges associated with appropriate mechanics which afford such straightedges a wide range of movement in two orthogonal degrees of freedom over the face of a drawing surface. Such a drafting machine is described in U.S. Pat. No. 3,279,073.
  • the drafting device ploys a magnetized roller which is strongly retained by magnetic attraction in close association with a ferrous drafting board.
  • the force of the magnetic field generated by the magnetic elements of the roller effectively prevents movement of the roller in any direction but that transverse to the axis of the roller, i.e., a straight and true rolling movement of the roller guide element is established regardless of the attitude of the drafting board.
  • the present drafting device further comprises a yoke element which overlies the roller, engaging the surface of the latter at internal concave bearing faces by means of which the yoke can readily ride with the rolling movement of the roller or slide axially upon the circumferential surface of the roller.
  • the yoke member is thereby afforded two precisely orthogonal degrees of movement.
  • a line guide member such as a drafting triangle or the like, which comprises two orthogonally disposed straightedges, one of which is parallel to the axis of the roller element engaging faces of the yoke member.
  • the straightedges are thus adapted to respectively maintain parallelism regardless of the movement of the line guide element upon the drafting surface.
  • the magnetic attraction between the drafting device roller element and the ferrous drafting board serves an additional practical function.
  • a sheet of drawing paper or similar drafting medium overlays the board element and is retained in a fixed relation to the board element by the magnetized roller element positioned upon the sheet.
  • This fixed relation and disposition between the board, paper, and roller element establish a base line for the drawing which remains true throughout the operation of the drafting device.
  • the drawing base line may be later quickly reestablished and retained throughout the further use of the drafting device.
  • the use of tapes and tracks are additionally obviated, thereby providing a greater useful area on the drafting medium.
  • FIG. 1 is a plan view of a drafting device according to the present invention
  • FIG. 2 is a partial section view of the drafting device taken at 2-2 ofFlG. 1;
  • FIG. 4 is a view, partially in section, of a segment of another embodiment of the magnetized roller member of the present invention.
  • FIG. 1 A preferred embodiment of the portable drafting device of the present invention is shown in FIG. 1 and generally comprises a drafting member assembly 10, a magnetic roller member 11 and a drafting board member 20.
  • the drafting member assembly 10 comprises a yoke element 14 to which is rigidly attached a line guide element 16.
  • Guide element 16 is preferably a transparent acrylic sheet having the form of a common drafting triangle.
  • a major straightedge of the triangle may be conveniently marked in units of measure and serves as one of a pair of orthogonal lining guides.
  • a slot 17 in the body of the triangle provides the second of the line guide straightedges which may be similarly marked in units of measure.
  • a protractor segment 18 having indexing indicia (not shown) is mounted for rotation in a known manner at a circular cutout in the body of triangle element 16. Slots 19 provide finger access to assist in rotary movement of protractor element l8.
  • Roller member 11 comprises a cylindrical body 12 having magnetic elements 13 affixed axially at both ends of the body, thereby forming a magnetic rod or roller which is strongly attracted to any ferrous body.
  • the construction of roller member 1 l is shown in greater detail in FIG. 3.
  • Drafting board member 20 is a generally rectangular sheet of steel or other ferrous material which is of sufficient thickness to provide a practical degree of rigidity.
  • One edge of drafting board 20 is partially folded back upon itself to form a straightedge lip 21 which serves during operation of the drafting device as the primary baseline guide and additionally functions as a paper stop and alignment edge.
  • FIG. 1 A sheet of paper or other drafting medium 15 is set upon the surface of board member 20 and is pushed into squared abutment along one edge with drafting board corner 33 (FIG. 2).
  • roller member I After general orientation of the paper 15 upon board member 20, roller member I] is set upon the face of the paper in a position generally axially parallel to the baseline edge 31 of board lip 21.
  • the magnetic attraction of roller member 11 to board 20 firmly affixes the paper in generally squared position upon the face of the board.
  • Yoke 14 of drafting member assembly 10 is then set upon roller 11, closely engaging the roller at internal faces 26, 26' of like radius of curvature to the surface of roller 11.
  • the assembled combination 10, 11 is moved toward board lip 21 until yoke tail section 29 engages board lip 21 at baseline edge 31.
  • tail section 29 is not in contact with edge 31 along its entire length, sufficient force is applied to yoke 14 to overcome the magnetic attraction between the roller and the board member so that contact is made between the squaring edge 31 and yoke tail section 29 along the entire length of the latter.
  • This squaring operation establishes a baseline between the paper 15 and the lining straightedges of triangle 16 which may be readily reestablished by a like operation even after intermittent disassembly of the drafting device.
  • the assembled drafting device provides a truly orthogonal movement of the line guide element 16 and its associated straightedges. Horizontal movement is established through the rolling action of member 1 1 over the face of the board 20 and drafting sheet 15 while vertical movement is established by the axial sliding of yoke 14 on the face of roller member 11. Representative movement of the drafting member assembly 10 is shown at 10'.
  • protractor member 18 is inset into a circular guide in the body of triangle 16.
  • the protractor element is readily rotatable within the circular guide as indicated in phantom at 18'.
  • the drafting device is seen in preliminary squared baseline adjustment with the yoke tail section 29 in abutment with the squaring edge 31 of board lip 21.
  • a preferred construction of the device is also seen wherein yoke 14 is conveniently formed by extrusion from a non-ferrous material such as aluminum or plastic.
  • the inner surface of yoke 14 comprises two inward protruding ridges, the surfaces 26, 26 of which conform precisely in concave curvature to the circumferential curvature of the roller member as represented by the cylindrical tube roller body 12.
  • the concave surfaces 26, 26' present a low-friction bearing surface such as can readily be obtained by a layer of polytetrafluoroethylene bearing material or any of a number of commercially available bake-on" dry lubricants comprising, for example, mixtures of silicon, graphite, and epoxy resin binder.
  • a lip section 28 is conveniently included in the extruded form of yoke 14 and includes a channel generally parallel to the baseline alignment surface of yoke tail section 29 by means of which guideline element 16 may conveniently be affixed to yoke 14.
  • the joint between yoke 14 and guideline element 16 may be permanently achieved through the use of adhesive and press forming, or provision (not shown) may be included for removable attachment of guideline element 16 in order to provide interchangeability of various shapes of element 16.
  • roller 11 The construction of a preferred embodiment of roller 11 is shown in FIG. 3 and comprises a cylindrical, tubular roller body 12, preferably of non-ferrous material such as aluminum or plastic. At each end of body 12 there is inserted a soft iron bushing 37 having a center hole through which a non-ferrous threaded rod 36 is inserted. Arranged upon the extending ends of rod 36 are center-bored discs, or rings 13 of permanently magnetized material alternating with center-bored soft iron discs, or rings 35 which form pole pieces in the magnet assembly. Any desired number of elements in this alternating structure combination may be included and the assembly is finally completed by a tapped nut element 39, preferably of soft iron to act as the final pole piece of the assembly.
  • a tapped nut element 39 preferably of soft iron to act as the final pole piece of the assembly.
  • Magnetized disc elements of the present construction are commercially available and are preferably formed of pre magnetized ceramic composition or other permanently magnetized material, for example as described in U.S. Pat. No. 2,762,777.
  • the pre-magnetized discs are characteristically polarized in their axial direction and present a definite North pole at one face and South pole at the opposite face.
  • the pole dispositions are specifically noted in FIG. 3 where the preferred arrangement is depicted as the alternation of N-S elements 13 and S-N elements 13' along the length of roller 11.
  • This arrangement with the further inclusion of alternating soft iron ring discs 35 which act as pole pieces for the respective pairs 13, 13' of the magnetized discs result in a strong, closely-formed magnetic field along the whole surface of the magnet sections of roller 11.
  • a final operation in the construction of roller 11 comprises the centerless surface grinding of the entire member to achieve parallel surfaces to insure true rolling movement of the drafting device when in operation.
  • the radius of curvature of the surface of roller 11 may be conveniently adjusted to precisely conform with the radius of curvature of surfaces 26, 26 of yoke member 14 as previously noted.
  • FIG. 4 Another embodiment of a roller member is shown in FIG. 4 and comprises a solid cylindrical rod body element 41 of nonferrous metal or plastic to the ends of which are adhered, by epoxy adhesive composition or the like, alternating discs of soft iron 35 and magnetized ceramic 13 in the manner described previously.
  • the N-S discs 13 are similarly arranged in alternating sequence with S-N discs 13 with intervening soft iron pole pieces 35 to obtain the strong, directed magnetic field as earlier described.
  • Yet another embodiment in the construction of the magnetized roller may include the use of a combination of a central alignment rod and a tubular body section as in FIG. 3 with the adhesive junctures employed in the embodiment of FIG. 4. In any event, the final operation of centerless gnndrng to achieve true rolllng surfaces and close mating with the curvature of surfaces 26, 26' of yoke 14 completes the construction of the magnetized roller.
  • the drafting device of the present invention has been found to provide in its movement and manner of handling, a convenient and faithful reproduction of the larger, premanentlyaffixed beam-type drafting machines. Besides providing a handy tool for the traveling design engineer, the drafting device represents a particularly useful training apparatus for engineering students due to the faithful duplication of commercial drafting machines in all its movements.
  • the invention provides a low-cost, readily-portable replica of more expensive drafting machines and provides students with an early opportunity to become well acquainted with the manner of operation of apparatus which they would not ordinarily encounter until their employment years.
  • a portable drafting device comprising, in combination:
  • a drafiing board member comprising a substantially flat magnetically attractable working surface
  • a line guide member comprising a yoke element encompassing a substantial segment of the circumferential surface of said roller member, said yoke element including bearing means engaging said roller surface at a plurality of points defining at least one roller surface area which intersects a plane which is perpendicular to said board member and contains the axis of the roller, thereby establishing two orthogonal degrees of freedom for movement of said line guide member with respect to said board member.
  • said drafting board member includes an upstanding wall segment presenting abutment surface portions respectively providing bases of alignment between said board and a paper sheet overlaying said board, and between said board and said roller member.
  • a device according to claim 2 wherein said abutment surface portions present substantially parallel base lines of reference for alignment of said roller member and at least one straight edge of a sheet of paper overlaying said board.
  • said yoke element bearing means comprises a planoconcave surface having a radius of curvature equal to the radius of curvature of the curvature of the circumferential surface of said roller member.
  • said yoke element includes a substantially vertically disposed surface portion forming an abutment edge which is substantially parallel to the axis of curvature of said plano-concave bearing surface.
  • roller member comprises a plurality of magnetized cylindrical segments axially affixed to a cylindrical body and of like circumference thereto, said magnetized segments each exhibiting a north and a south magnetic pole.
  • said drafting board member comprises a substantially rectangular rigid flat plate of ferro-metallic material, said plate having at least one straight edge and having a portion adjacent said straight edge folded back along a line parallel to said straight edge to yield an upstanding wall segment forming an acute angle with the remaining portion of said plate.
US122406A 1971-03-09 1971-03-09 Portable drafting device Expired - Lifetime US3672062A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US12240671A 1971-03-09 1971-03-09

Publications (1)

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US3672062A true US3672062A (en) 1972-06-27

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US122406A Expired - Lifetime US3672062A (en) 1971-03-09 1971-03-09 Portable drafting device

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US (1) US3672062A (US06811534-20041102-M00003.png)
JP (1) JPS511173B1 (US06811534-20041102-M00003.png)
AU (1) AU454619B2 (US06811534-20041102-M00003.png)
BE (1) BE780193A (US06811534-20041102-M00003.png)
BR (1) BR7201276D0 (US06811534-20041102-M00003.png)
CA (1) CA959255A (US06811534-20041102-M00003.png)
CH (1) CH547714A (US06811534-20041102-M00003.png)
DE (1) DE2210807B2 (US06811534-20041102-M00003.png)
DK (1) DK138981B (US06811534-20041102-M00003.png)
FR (1) FR2131991B1 (US06811534-20041102-M00003.png)
GB (1) GB1375065A (US06811534-20041102-M00003.png)
IT (1) IT957539B (US06811534-20041102-M00003.png)
NL (1) NL7202881A (US06811534-20041102-M00003.png)
SE (1) SE374892B (US06811534-20041102-M00003.png)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4403423A (en) * 1979-09-07 1983-09-13 Ford Alan T Drafting instrument
US4823475A (en) * 1988-03-21 1989-04-25 Hoegh Poul E Drafting device
US4934061A (en) * 1986-04-03 1990-06-19 Jonathan Knight Draughting tables, drawing boards, drawing instruments and analogous apparatus
US5012586A (en) * 1989-08-28 1991-05-07 Ashworth Anthony J Plotting and drafting apparatus with magnetic guide
USRE33654E (en) * 1988-03-21 1991-08-06 Drafting device
US5343625A (en) * 1992-11-25 1994-09-06 Chen Chiang M Portable magnetic drafting board
US7895760B1 (en) * 2006-12-06 2011-03-01 Bareis Kathryn M Universal design sheet material holder assembly

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2213947A (en) * 1987-12-23 1989-08-23 Keith Wah Chan Drawing instrument

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2360911A (en) * 1941-02-04 1944-10-24 William H Tress Navigational plotter
US2689404A (en) * 1951-07-13 1954-09-21 Pettersen Mfg Company Pointer attachment for straight edge and roller assemblies
US3122840A (en) * 1960-08-08 1964-03-03 Karstens Edward Siegfried Precision leveling device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1686980A (en) * 1927-07-26 1928-10-09 Claude C Nuckols Drawing board and attached straightedge
FR1206363A (fr) * 1958-08-13 1960-02-09 Appareil à dessiner magnétique

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2360911A (en) * 1941-02-04 1944-10-24 William H Tress Navigational plotter
US2689404A (en) * 1951-07-13 1954-09-21 Pettersen Mfg Company Pointer attachment for straight edge and roller assemblies
US3122840A (en) * 1960-08-08 1964-03-03 Karstens Edward Siegfried Precision leveling device

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4403423A (en) * 1979-09-07 1983-09-13 Ford Alan T Drafting instrument
US4934061A (en) * 1986-04-03 1990-06-19 Jonathan Knight Draughting tables, drawing boards, drawing instruments and analogous apparatus
US4823475A (en) * 1988-03-21 1989-04-25 Hoegh Poul E Drafting device
USRE33654E (en) * 1988-03-21 1991-08-06 Drafting device
US5012586A (en) * 1989-08-28 1991-05-07 Ashworth Anthony J Plotting and drafting apparatus with magnetic guide
US5343625A (en) * 1992-11-25 1994-09-06 Chen Chiang M Portable magnetic drafting board
US7895760B1 (en) * 2006-12-06 2011-03-01 Bareis Kathryn M Universal design sheet material holder assembly

Also Published As

Publication number Publication date
JPS511173B1 (US06811534-20041102-M00003.png) 1976-01-14
DE2210807A1 (de) 1972-09-14
DK138981B (da) 1978-11-27
AU454619B2 (en) 1974-10-11
CH547714A (fr) 1974-04-11
BE780193A (fr) 1972-07-03
BR7201276D0 (pt) 1973-06-14
DE2210807B2 (de) 1975-12-04
DK138981C (US06811534-20041102-M00003.png) 1979-05-14
AU3965272A (en) 1973-09-13
NL7202881A (US06811534-20041102-M00003.png) 1972-09-12
FR2131991B1 (US06811534-20041102-M00003.png) 1976-06-11
FR2131991A1 (US06811534-20041102-M00003.png) 1972-11-17
CA959255A (en) 1974-12-17
GB1375065A (US06811534-20041102-M00003.png) 1974-11-27
SE374892B (US06811534-20041102-M00003.png) 1975-03-24
IT957539B (it) 1973-10-20

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AS Assignment

Owner name: CHEMICAL BANK, A BANKING INSTITUTION OF, NEW YORK

Free format text: SECURITY INTEREST;ASSIGNOR:KEUFFEL & ESSER COMPANY A.N.J. CORP;REEL/FRAME:003969/0808

Effective date: 19820323

Owner name: BANK OF CALIFORNIA N.A. THE; A NATIONAL BANKING AS

Free format text: SECURITY INTEREST;ASSIGNOR:KEUFFEL & ESSER COMPANY A.N.J. CORP;REEL/FRAME:003969/0808

Effective date: 19820323

Owner name: CONTINENTAL ILLINOIS NATIONAL BANK & TRUST CO., OF

Free format text: SECURITY INTEREST;ASSIGNOR:KEUFFEL & ESSER COMPANY A.N.J. CORP;REEL/FRAME:003969/0808

Effective date: 19820323

Owner name: CHEMICAL BANK, A BANKING INSTITUTION OF NY.

Free format text: SECURITY INTEREST;ASSIGNOR:KEUFFEL & ESSER COMPANY A.N.J. CORP;REEL/FRAME:003969/0808

Effective date: 19820323

Owner name: CHASE MANHATTAN BANK, N.A. THE; A NATIONAL BANKING

Free format text: SECURITY INTEREST;ASSIGNOR:KEUFFEL & ESSER COMPANY A.N.J. CORP;REEL/FRAME:003969/0808

Effective date: 19820323

Owner name: SECURITY NATIONAL BANK, A NATIONAL BANKING ASSOCIA

Free format text: SECURITY INTEREST;ASSIGNOR:KEUFFEL & ESSER COMPANY A.N.J. CORP;REEL/FRAME:003969/0808

Effective date: 19820323