EP0065375B1 - Set square - Google Patents
Set square Download PDFInfo
- Publication number
- EP0065375B1 EP0065375B1 EP19820302248 EP82302248A EP0065375B1 EP 0065375 B1 EP0065375 B1 EP 0065375B1 EP 19820302248 EP19820302248 EP 19820302248 EP 82302248 A EP82302248 A EP 82302248A EP 0065375 B1 EP0065375 B1 EP 0065375B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- set square
- angles
- straight edge
- edge portions
- line
- 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
Links
Images
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
- B43L7/00—Straightedges
- B43L7/027—Plural non-adjustable straightedges fixed at right angles
- B43L7/0275—Triangles
Definitions
- the present invention relates to a set square.
- Set squares in general are well known.
- the usual form is that of a right angled triangle whose other angles are both 45° or are 60° and 30°.
- the square is commonly made of a plastics material or metal.
- Patent US-A-2,043,729 discloses a 90/45/45° set square having three cut-outs which provide various straight edges at predetermined angles to external edges.
- US-A-1,598,690 discloses a 90/60/30° set square with three apertures (a slot and two triangles) for providing further angles. The triangles are right-angled, with the perpendicular sides parallel to those of the set-square. Thus only the hypotenuses provide additional angles. Generally, a given angle is obtainable only relative to one particular external side. Thus the user must locate the square the correct way up, and select the correct aperture.
- a substantially triangular set square having three external straight edge portions with angles of 30°, 60° and 90° defined by respective pairs thereof, and an internal substantially triangular aperture having respective straight edge portions which define angles of 15° and 45° with each of the external straight edge portions.
- a draughtsman using a T-square can set the four usual angles (30, 45, 60, 90°), and also obtain angles of 15° and 75°.
- the straight edge portions of the aperture define a 30°, 30°, 120° triangle.
- a user even without a T-square, can set angles precisely. Angles can be drawn easily and accurately, particularly interior angles of the aperture, but also angles formed by one side of the cut-out and one external edge portion. Use of the interior angles to draw vertices is of course not affected by the degradation of the external corner portions of the square, which commonly happens in use.
- a straight line at right-angles to one of the external straight edge portions other than that defining the hypotenuse said line traversing the aperture.
- This line can be used to set 45, 60, 75 and 90° angles precisely, without the need for a T-square. The line is then used as a reference instead of an external edge/portion.
- protractor scale arranged so that the origin of the protractor is at the intersection of said line and the straight edge portion at right angles thereto, said line indicating the 90° line of the protractor. Having the origin of the protractor at the edge makes the protractor particularly simple to use, e.g. for setting the square at any desired angle to a given line.
- the versatility of the implement can be increased by providing one or more of the edge portions with measuring scales and/or by providing a plurality of holes at predetermined spacings for receiving pencil points for drawing arcs of predetermined radii.
- the set square 1 shown in Figures 1 and 2 has the general form of a 30/60/90° triangle ABC, having sides a and c at right angles, and side b as hypotenuse. Angles A and C are 30° and 60° respectively.
- An aperture 2 has the form of a 30/30/120° triagnel PQR, the sides p and r and the angles P and R being equal. It is oriented so that its longest side q is adjacent the hypotenuse b, and makes an angle of 15° therewith, approaching nearer it towards the vertex C.
- the single cut-out 2 provides angles of 15° and 45° to each external side a, b, c as follows:
- Angles of 75° to sides a and c are also provided, by sides r and p respectively.
- the square 1 may bear indicia for showing the user where to obtain various angles.
- a line 3 is indicated (suitably by an inked indentation), extending at right angles to edge c from a point 0 thereon.
- the line 3 is interrupted by the aperture 2, and continues on the other side thereof until it reaches an arcuate slot 4 furnished with protractor scales 5.
- the slot and scales have their centre of origin at 0.
- the edge c and the line 3 are respectively the 0/180° and 90° lines of the protractor.
- the square 1 can easily be positioned at any desired angle to a given line.
- the slot 4 extends only over about 95°, angles up to 180° can be measured or set by using either the edge c or the line 3 as the reference line. Having the line 3 traverse the aperture 2 makes it easy to align with a line on a drawing even if the square 1 is opaque.
- the longer external sides b, c are provided with scales 7 graduated in inches and centimetres respectively.
- Adjacent side c is a line of small apertures 8: five with 2 mm spacings, seven more at 1 cm spacings, and another 7 cm from the last of these.
- the apertures 8 are dimensioned to receive pencil points with minimal play, so that arcs of known radii can be drawn using two pencils.
- This instrument design does not necessitate transparency, and it may be manufactured in any suitable material such as metal or plastics by any conventional means. If sheet metal or plastics is to be used, section X-Y in Figure 2 shows typically how its structure can be stiffened to minimise the material thickness and weight, and also provide additional benefits. A fold 9 can be pressed or moulded all round the periphery of the instrument, resulting in bevelled edges 10 for the scales 7. This not only provides stiffening, but improves the appearance, and also enables the instrument to be used face down with advantage when using pen and ink, to discourage running of the ink as may occur with a flat surface against the paper.
- Figure 3 shows an alternative arrangement with an aperture 2' formed as a 30/60/90° triangle XYZ with sides x, y, z.
- the hypotenuse y is at 15° to side b, and 45° to side a.
- the shortest side z is at 15° to side c, and 45° to side a.
- the other side x is at 15° to side a and 45° to side b.
Landscapes
- Length-Measuring Instruments Using Mechanical Means (AREA)
Description
- The present invention relates to a set square.
- Set squares in general are well known. The usual form is that of a right angled triangle whose other angles are both 45° or are 60° and 30°. The square is commonly made of a plastics material or metal.
- Numerous proposals have been made to render set squares more versatile. However none of these seems to have had any success. This is probably because they either add little to the potential utility of the square, or because they are so complicated as to frighten off potential users and/or to increase manufacturing costs substantially.
- For example, Patent US-A-2,043,729 (Bilder) discloses a 90/45/45° set square having three cut-outs which provide various straight edges at predetermined angles to external edges. There are also numerous apertures for use in drawing circles, and a protractor scale. The whole is of dauntingly complicated appearance, and would apparently require much practice to master. US-A-1,598,690 (Petronio) discloses a 90/60/30° set square with three apertures (a slot and two triangles) for providing further angles. The triangles are right-angled, with the perpendicular sides parallel to those of the set-square. Thus only the hypotenuses provide additional angles. Generally, a given angle is obtainable only relative to one particular external side. Thus the user must locate the square the correct way up, and select the correct aperture. There is also a protractor scale, symmetrical about the 90° angle of the square, its origin indicated by an aperture.
- Further examples of patent specifications disclosing modified set-squares are:
- FR-A-9081 63 (Vardanian)
- FR-A=934943 (Le Material Automatique Electrique)
- FR-A-957869 (Lewin)
- FR-A-981857 (Cordani)
- FR-A-1124247 (Balloche)
- FR-A-1208614 (Hoellinger)
- FR-A-2351801 (Bord)
- US-A-1845449 (Smith)
- US-A-3375589 (Dolgorukov)
- CH-A-276736 (Clerc)
- GB-A-794192 (Midulla)
- According to the present invention there is provided a substantially triangular set square having three external straight edge portions with angles of 30°, 60° and 90° defined by respective pairs thereof, and an internal substantially triangular aperture having respective straight edge portions which define angles of 15° and 45° with each of the external straight edge portions.
- By means of such a set square, a draughtsman using a T-square can set the four usual angles (30, 45, 60, 90°), and also obtain angles of 15° and 75°.
- Preferably the straight edge portions of the aperture define a 30°, 30°, 120° triangle. Then a user, even without a T-square, can set angles precisely. Angles can be drawn easily and accurately, particularly interior angles of the aperture, but also angles formed by one side of the cut-out and one external edge portion. Use of the interior angles to draw vertices is of course not affected by the degradation of the external corner portions of the square, which commonly happens in use.
- Preferably there are means indicating a straight line at right-angles to one of the external straight edge portions other than that defining the hypotenuse, said line traversing the aperture. This line can be used to set 45, 60, 75 and 90° angles precisely, without the need for a T-square. The line is then used as a reference instead of an external edge/portion.
- Preferably there are means defining a protractor scale arranged so that the origin of the protractor is at the intersection of said line and the straight edge portion at right angles thereto, said line indicating the 90° line of the protractor. Having the origin of the protractor at the edge makes the protractor particularly simple to use, e.g. for setting the square at any desired angle to a given line.
- The versatility of the implement can be increased by providing one or more of the edge portions with measuring scales and/or by providing a plurality of holes at predetermined spacings for receiving pencil points for drawing arcs of predetermined radii.
- There may be indicia indicating the angular relationships of at least some of the straight edge portions.
- Some preferred embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:
- Figure 1 is a plan view of a preferred embodiment of a set square according to the invention;
- Figure 2 is a section along XY in Figure 1; and
- Figure 3 is a schematic view of a second embodiment.
- The
set square 1 shown in Figures 1 and 2 has the general form of a 30/60/90° triangle ABC, having sides a and c at right angles, and side b as hypotenuse. Angles A and C are 30° and 60° respectively. Anaperture 2 has the form of a 30/30/120° triagnel PQR, the sides p and r and the angles P and R being equal. It is oriented so that its longest side q is adjacent the hypotenuse b, and makes an angle of 15° therewith, approaching nearer it towards the vertex C. - Thus, the single cut-out 2 provides angles of 15° and 45° to each external side a, b, c as follows:
-
- As indicated at 6, the
square 1 may bear indicia for showing the user where to obtain various angles. - A
line 3 is indicated (suitably by an inked indentation), extending at right angles to edge c from apoint 0 thereon. Theline 3 is interrupted by theaperture 2, and continues on the other side thereof until it reaches anarcuate slot 4 furnished with protractor scales 5. The slot and scales have their centre of origin at 0. The edge c and theline 3 are respectively the 0/180° and 90° lines of the protractor. Thus thesquare 1 can easily be positioned at any desired angle to a given line. Although theslot 4 extends only over about 95°, angles up to 180° can be measured or set by using either the edge c or theline 3 as the reference line. Having theline 3 traverse theaperture 2 makes it easy to align with a line on a drawing even if thesquare 1 is opaque. - The longer external sides b, c are provided with
scales 7 graduated in inches and centimetres respectively. Adjacent side c is a line of small apertures 8: five with 2 mm spacings, seven more at 1 cm spacings, and another 7 cm from the last of these. Theapertures 8 are dimensioned to receive pencil points with minimal play, so that arcs of known radii can be drawn using two pencils. - This instrument design does not necessitate transparency, and it may be manufactured in any suitable material such as metal or plastics by any conventional means. If sheet metal or plastics is to be used, section X-Y in Figure 2 shows typically how its structure can be stiffened to minimise the material thickness and weight, and also provide additional benefits. A fold 9 can be pressed or moulded all round the periphery of the instrument, resulting in
bevelled edges 10 for thescales 7. This not only provides stiffening, but improves the appearance, and also enables the instrument to be used face down with advantage when using pen and ink, to discourage running of the ink as may occur with a flat surface against the paper. - Although the arrangement shown in Figure 1 is felt to be particularly useful, others are possible and may be favoured in some circumstances. Other shapes and orientations of the
aperture 2 are possible, while still giving the desired angles with the external sides. Thus Figure 3 shows an alternative arrangement with an aperture 2' formed as a 30/60/90° triangle XYZ with sides x, y, z. The hypotenuse y is at 15° to side b, and 45° to side a. The shortest side z is at 15° to side c, and 45° to side a. The other side x is at 15° to side a and 45° to side b.
Claims (9)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8113988 | 1981-05-07 | ||
GB8113988 | 1981-05-07 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0065375A1 EP0065375A1 (en) | 1982-11-24 |
EP0065375B1 true EP0065375B1 (en) | 1984-11-28 |
Family
ID=10521636
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19820302248 Expired EP0065375B1 (en) | 1981-05-07 | 1982-04-30 | Set square |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0065375B1 (en) |
DE (1) | DE3261353D1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106079978A (en) * | 2016-08-11 | 2016-11-09 | 鲁子航 | Lattice rule |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1598690A (en) * | 1924-10-23 | 1926-09-07 | Jerome A Petronio | Drafting triangle |
DE585040C (en) * | 1931-12-15 | 1933-09-28 | Christof Kammerer | Right-angled triangle |
US2043729A (en) * | 1932-06-08 | 1936-06-09 | James K Bilder | Drafting instrument |
CH205209A (en) * | 1938-09-15 | 1939-06-15 | Sartori Antonio | Drawing angle. |
-
1982
- 1982-04-30 EP EP19820302248 patent/EP0065375B1/en not_active Expired
- 1982-04-30 DE DE8282302248T patent/DE3261353D1/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
EP0065375A1 (en) | 1982-11-24 |
DE3261353D1 (en) | 1985-01-10 |
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