GB2486235A

GB2486235A - Integrated drawing tool

Info

Publication number: GB2486235A
Application number: GB1020765.2A
Authority: GB
Inventors: Mister King Yan Cheung
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-12-08
Filing date: 2010-12-08
Publication date: 2012-06-13
Also published as: GB201020765D0

Abstract

A drawing tool 1 includes a protractor 2, a ruler 6 rotatably mounted to the protractor 2, and a pointer 17 slidably mounted on top of the ruler 6. The protractor 2 may be provided with an optical magnifying means 4 along its periphery and an optical magnifying optical means 5 at its centre. The ruler 6 includes a linear precision scale 7 on at least one side thereof, and may have a rectangular hole 8 along its central longitudinal axis 32, and a guard 21 at its free longitudinal end. The pointer 17 may be provided with holes 9, 11, 13, 19, optical magnifying means 10, 12, 18, 20, supports (27, 28, 29, 30, Fig.4), and locking means 14, 15, 16 which is operable to lock the pointer 17 against movement relative to the ruler 6.

Description

INTEGRATED DRAWING TOOL

The present invenlion relates to an integrated drawing tool for measuring and drawing angles, straight lines, parallel lines, circular ares and circles, on drawing surfaces, such as paper, black boards, white boards and other similar surfaces.

Background of the Invention

It is known to provide a protractor for measuring and drawing angles on paper, black boards, and white boards, in teaching and learning activities, or others involving similar surfaces. The protractor may be part of a set, known as a multif unction protractor ruler compass set, in which a ruler and a pointer are also provided.

A problem of these rnultifunction protractor ruler compass sets is that they can only be used on paper, or white boards, or black boards, or similar surfaces individually. They work well on some but not on all of these surfaces.

Another problem of these sets is that they use an internal or an external sharp point to locate and fix the position of a point, which causes a potential threat to the user and the surfaces to be drawn.

Some of such sets use a suction cup to locate and fix the position of a point, which is cumbersome and inaccurate.

Some of these conventional sets provide a protractor to be used independently but not as an integrated part of the whole.

All of these existing sets are bulky and clumsy to use, and therefore use up much raw material in manufacturing.

On top of these problems, none of these sets provides angular and linear precision scales.

One final common problem of these sets is that once any part of them is broken or worn out they have to be thrown away and replaced by a whole new set.

It is therefore an object of the present invention to provide a drawing tool which reduces, obviates or mitigates the problems associated with such conventional multifunction protractor ruler compass sets, or at least to provide a useful alternative to the trade and public.

Stalement of Invention According to the present invention, there is provided a drawing tool comprising a protractor having an angular precision scale and a shaft, a ruler having a linear precision scale on at least one side thereof, wherein the ruler is engaged with the protractor, wherein a pointer is mounted on top of the ruler, wherein the ruler is rotatable relative to the protractor, and wherein the pointer is slidabe along the ruler.

Advantageously, the drawing tool may further include optical magnifying means for obtaining clear reading of the angular precision scale of the protractor.

The drawing tool may advantageously further include optical magnifying means for locating and fixing the position of a point.

Suitably, the drawing tool may further include means for preventing the protractor from direct contact with the ruler.

Convenienfly, the drawing tool may further include means for automatically stopping movement of the ruler relative to the protractor and retaining the position of the ruler relative to the protractor.

The drawing tool may advantageously further include means for preventing the pointer from sliding off the ruler.

The pointer of the drawing tool may suitably include optical magnifying means for magnifying readings of the linear precision scale of the ruler.

The drawing tool may conveniently further include means for locking the pointer in position against movement relative to the ruler.

Advantageously, the drawing tool may further include means allowing insertion of at least one writing implement.

Suitably, the drawing tool may further include means for preventing the drawing tool proper from direct contact with the drawing surfaces.

Conveniently, the protractor of the drawing tool may be approximately 2 cm in diameter and 2 mm in thickness.

The ruler of the drawing tool may advantageously be approximately 1 cm in width, 11 cm in length and 2 mm in thickness.

The pointer of the drawing tool may suitably be approximately 1.4 cm in width, 3 cm in length and 4 mm in thickness.

The drawing tool may conveniently further include means allowing drawing of a straight line along a central longitudinal axis of the ruler.

Advantageously, the drawing tool may be adapted to be used on paper, white board, black board, and other similar surfaces.

Brief Description of the Drawings

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will be made, by way of example, to the accompanying drawings, in which: Figure 1 shows a schematic perspective view of a drawing tool according to an embodiment of the present invention with the locking means in a locked position; Figure 2 shows a schematic top view of the drawing tool of Figure 1; Figure 3 shows a schematic side view of the drawing tool of Figure 1; Figure 4 shows a schematic bottom view of the drawing tool of Figure 1; Figure 5 shows an enlarged schematic front view of the drawing tool of Figure 1; Figure 6 shows an enlarged schematic rear view of the drawing tool of Figure 1; Figure 7 shows how the various parts of the drawing tool of Figure 1 can be assembled; Figure 8 shows how the drawing tool of Figure 1 can be used to measure a given angle; Figure 9 shows how the drawing tool of Figure 1 can be used to construct a line segment congruent to a given line segment; Figure 10 shows how the drawing tool of Figure 1 can be used to construct a cirde of a radius of a given length; and Figure 11 shows how the drawing tool of Figure 1 can be used to construct a parallelogram of given lengths and angles.

Description of a Preferred Embodiment

Referring firstly to Figure 1, a drawing tool is indicated generally as 1. The drawing tool 1 includes a protractor 2, a ruler 6 pivotally mounted at one longitudinal end to the protractor 2, and a pointer 17 mounted on top of the ruler 6. The protractor 2 is provided with an angular precision scale 3 along its periphery, as shown in Figures 1, 2, 4 and 5. The angular precision scale 3 may be precise approximately up to 0.5 degree. The protractor 2 is approximately 2 cm in diameter. The ruler 6 may be of a length of approximately 11 cm, a width of approximately 1 cm and a thickness of approximately 2.0 mm. The pointer 17 is approximately 3.0 cm in length, 1 A cm in width and 4.0 mm in thickness.

An optical magnifying means 4 is provided, as shown in Figures 1, 2, 3, and 5, at a location along the periphery of the protractor 2. Another optical magnifying means 5 is provided, as shown in Figures 1 and 2, at the centre of the protractor 2. The optical magnifying means 4, 5 may be transparent hemispherical portions or convex portions protruding upwards from the upper surface of the protractor 2, which optically magnify readings of the angular precision scale 3, thus facilitating accurate measurement of angles and drawings.

At the base of the protractor 2, a cylindrical shaft 26 is provided, as shown in Figures 4, 5, and 7. As shown in Figure 5, a cylindrical shaft 26 snap-fits into a hollow cylindrical springy shaft 24 of a split hollow cylindrical springy shaft 25, which is of a diameter of approximately 0.4 cm. The split hollow cylindrical springy shaft 25 has a wide base 23 of a height of around 1.0 mm, as shown in Figures 4, and 5, so that the protractor 2 can stand stably on its own on this base 23. The hollow cylindrical shaft 24, which is of a diameter of approximately 0.4 cm, is longer than the cylindrical shaft 26, as shown in Figure 5. The cylindrical shaft 24, the split hollow cylindrical springy shaft 25 and the cylindrical shaft 26 are concentric with one another and are rotatable relative to one another about their common central longitudinal axis, so that the protractor 2 can be rotated to any angular position relative to the ruler 6. In addition, by way of such an arrangement, the protractor 2 is not in direct contact with the ruler 6.

As the split hollow cylindrical springy shaft 25 is split and is made of a resilient/springy material, the shaft 24 (which is also split) is provided with a reasonably powerful grip on the cylindrical shaft 26 of the protractor 2. In particular, when assembled, the shaft 24 wraps around the cylindrical shaft 26 of the protractor 2 and acts like a spring clip. Once the protractor 2 is rotated to a desired position relative to the ruler 6, the protractor 2 will stop in that position automatically. The protractor 2 and the ruler 6 will remain in that relative position unless sufficient force is exerted on the protractor 2 or the ruler 6 to overcome the grip of the cylindrical shaft 24 on the cylindrical shaft 26 of the protractor 2.

Such an arrangement can avoid accidental relative rotational movement between the protractor 2 and the ruler 6, in parficular once a desired relative position between them has been reached.

The ruler 6 is fitted pivotally onto the hollow cylindrical shaft 24 of the split hollow cylindrical springy shaft 25, as shown in Figures 3, 4 and 5. The ruler 6 is provided with a linear precision scale 7 on each of its two lateral sides, as shown in Figures 1 and 2. The linear precision scales 7 may be metric (and may be precise approximately up to 0.5 mm), or Imperial, or both. An elongate rectangular hole 8 of a width of approximately 1.0 mm is provided along a central longitudinal axis 32 of the ruler 6, as shown in Figures 1, 2 and 4, such that straight lines passing through the centre of the protractor 2 can be drawn along the hole 8. A hole is provided at another longitudinal end of the ruler 6, such that a pin 31, as shown in Figures 3 and 4, of a drawing pin shaped guard can pass through. A hemispherical head 21, as shown in Figures 1, 2 and 3, of the drawing pin shaped guard prevents the pointer 17 from sliding off the ruler 6. A tongue and groove joint 22, as shown in Figures 1, 3, 4 and 6, is provided on each of the two sides of the ruler 6 such that the pointer 17 can be mounted onto the ruler 6.

The tongue and groove joints 22 also act as rails on which the pointer 17 can slide along freely, as shown in Figures 1, 3, 4 and 6.

The pointer 17 is mounted on top of the ruler 6, as shown in Figures 1, 2, 3, 4, and 6 by tongue and groove jointing. Supports 27, 28, 29, 30, as shown in Figures 1, 3, 4, and 6, are provided on the lower surface of the pointer 17. The supports 27, 28, 29, 30, which may be of a height of 1.0 mm, raise the pointer 17 and the ruler 6 above the drawing surface. Conical insertion holes 9, 11, 13 and 19, as shown in Figures 1, 2, and 4, of a diameter of approximately 2.0 to 1.0 mm are provided, allowing insertion of wrfting implements, e.g. pens or pencils, such that the writing ends of such writing instruments can touch and draw on the drawing surface in contact with the supports 27, 28, 29, 30. Optical magnifying means 10, 12, 18, and 20, as shown in Figures 1, 2, 3, and 6, are provided for magnifying readings on the linear scales 7 of the ruler 6, so as to assist in obtaining accurate and precise readings on the linear scales 7. The optical magnifying means 10, 12, 18, and 20 may be transparent hemispherical portions or convex portions protruding upwards from the upper surface of the pointer 17.

A spring lock with an upper part 16 is provided in which the upper part 16 can be depressed and flipped, by the thumb of a user while the index and third fingers of the user hold a writing implement, into a catch 14, as shown in Figures 1, 2, 3 and 6, thus locking the pointer 17 in any desired position relative to the ruler 6. A lower part 15 of the spring lock, as shown in Figures 1 and 2, is curved and springy. When the pointer 17 is no longer required to be locked against movement relative to the ruler 6, the upper part 16 of the spring lock can be undone, thus releasing the locking of the spring lock. Thus, by way of this arrangement, the pointer 17 can be movable relative to the ruler 6, and can also be locked against movement relative to the ruler 6.

Referring to Figure 7, the upper part 16 and lower part 15 of the spring bck are inserted into the pointer 17. The pointer 17 is then mounted on top of the ruler 6 along the tongue and groove joints 22. The pin 31 of the drawing pin shaped guard is threaded through the hole at the longitudinal free end of the ruler 6, and thus securing the head 21 in place. The head 21 prevents the pointer 17 from sliding off the ruler 6. The ruler 6 is coupled with the hollow cylindrical springy shaft 24. The protractor 2 is then fitted into the hollow cylindrical springy shaft 24.

By way of such an arrangement, when assembled, the ruler 6 and the protractor 2 are supported above the drawing surface by the base 23 and the pin 31. Such an arrangement reduces wear and tear of the protractor 2 and the ruler 6 resulting from directly rubbing against the drawing surfaces. If required, the various parts of the drawing tool I can be taken apart in a reverse order of the process described above, replaced and reassembled.

Figure 8 shows how the drawing tool I can be used to measure the size of a given angle ABC. The ruler 6 is rotated such that a central longitudinal axis 32 (shown in Figures 1 and 2) is aligned with a zero-degree marking of the protractor 2. The point B of angle ABC is then located and fixed by looking through the optical magnifying means 5 of the protractor 2, and the elongate rectangular hole 8 aligned with arm BC of angle ABC. With a finger of the left hand of the user holding the protractor 2 in position, the ruler 6 is then rotated relative to the protractor 2 in the direction of the arrow by the right hand of the user until the rectangular hole 8 is aligned with arm BA of angle ABC. The size of angle ABC can then be read off the precision scale 3 through the optical magnifying means 4 of the protractor 2.

Figure 9 shows how the drawing tool I can be used to construct a line segment CD congruent to a given line segment AB. The ruler 6 is first rotated relative to the protractor 2 untfl the central longitudinal axis 32 (shown in Figure 2) is aligned with the 90degree marking of the protractor 2. A ray CE is then constructed with the rectangular hole 8 of the ruler 6. The point A is then located and fixed by looking through the optical magnifying means 5 of the protractor 2, and the central longitudinal axis 32 is aligned with line segment AS. With a finger of the left hand of a user holding the protractor 2 in position, the insertion hole 11 of the pointer 17 is moved, with the right hand of the user, to a position right on top of point B, and locked against movement relative to the ruler 6 by depressing and flipping the upper part 16 into the catch 14 of the spring lock. With point C as the centre and with AS as the radius, an arc is drawn, with a writing implement inserted into the insertion hole 11, to intersect ray CE at D. Line segment CD will be congruent to line segment AB. lf required, the exact length of CD can be read off the linear precision scale 7 of the ruler 6 through the optical magnifying means 12 of the pointer 17.

Figure 10 illustrates how the drawing tool 1 can be used to construct a circle with a radius of a given length, e.g. 3.0 cm. A ray OP is constructed with the rectangular hole 8 of the ruler 6. The drawing tool 1 is then moved along ray OR The point 0 is located and fixed through the optical magnifying means 5 of the protractor 2. Holding the protractor 2 in position with a finger of the left hand of a user, the pointer 17 is moved along ray OP, with the right hand of the user, until the insertion hole 11 is exactly 3.0 cm from point 0. This is assisted by reading off the linear precision scale 7 through the optical magnifying means 12 of the pointer 17. The pointer 17 is then locked in position against movement relative to the ruler 6. A circle is then drawn with a writing implement inserted into the insertion hole 11 and with the ruler 6 rotated about the central longitudinal axis of the protractor 2 for a full circle. The radius of the circle will be exactly 3.0 cm.

Figure 11 illustrates how the drawing tool 1 can be used to construct a parallelogram CDEF, with CD 4.0 cm long, CF 3.5 cm long, and containing an angie of 45 degrees. The ruler 6 is first rotated relative to the protractor 2 such that the central longitudinal axis 32 (shown in Figures 1 and 2) is aligned with the zero-degree marking of the protractor 2. Rays AB and CO are constructed with the parallel straight lateral edges of the ruler 6. The point A is then located and fixed through the optical magnifying means 5 of the protractor 2, and the central longitudinal axis 32 of the ruler 6 aligned with ray AB. With the protractor 2 being held in position, the ruler 6 is rotated such that its central longitudinal axis 32 is aligned with the 45-degree marking of the protractor 2. The protractor 2 is then moved along ray AB until point C is located and fixed in the rectangular hole 8 of the ruler 6. A ray CH is constructed with a writing implement inserted into and drawn along the rectangular hole 8. Wfth 4.0 cm as the length of the radius, an arc is drawn to intersect ray AB at M. With M as the centre, and with the central longitudinal axis 32 of the ruler 6 aligned with the 45-degree marking of the protractor 2, another ray DL is constructed with the rectangular hole 8 of the ruler 6 to intersect ray CO at D. With C as the centre, and 3.5 cm as the length of the radius, an arc is drawn to intersect ray CH at F. With D as the centre, and 3.5 cm as the length of the radius, another arc is drawn to intersect DL at E. Points F and E are then joined with a straight line to complete parallelogram CDEF.

It will be appreciated that the drawing tool 1 according to this invention is highly adaptable, since it can be used as a protractor, a ruler, a setsquare and a compass independently and integrally. It is of a small size, and therefore takes up a small volume of raw materials. It is convenient to store and carry. It provides angular and linear precision scales. It works equally well on paper, white boards, black boards or other similar surfaces. As the drawing tool 1 is supported by means such that it is not in direct contact with the surfaces to be drawn, it is more durable. It does not comprise any sharp point, and it does not need an external sharp point for locating and fixing the position of a point. it can be conveniently 1) taken apart, and the parts can be easfly replaced and reassembled if required.

The drawing tool 1 substantiafly obviates or at least mitigates the problems associated with existing multif unction protractor ruler compass sets.

Claims

CLA$MS 1. A drawing toot comprising a protractor having an angular precision scale and a shaft, a ruler having a linear precision scale on at least one side thereof, wherein the ruler is engaged with the protractor, wherein a pointer is mounted on top of the ruler, wher&n the ruler is rotatable relative to the protractor, and wherein the pointer is slidable along the ruler.
2. A drawing tool as claimed in claim 1, further including opUcal magnifying means for obtaining clear reading of the angular precision scale of the protractor.
3. A drawing tool as claimed in claim 1 or 2, further including optical magnifying means for locating and fixing the position of a point.
4. A drawing tool as claimed in any of the preceding claims, further including means for preventing the protractor from direct contact with the ruler.
5. A drawing tool as claimed in any of the preceding claims, further including means for automatically stopping movement of the ruler relative to the protractor and retaining the position of the ruler relative to the protractor.
6. A drawing tool as claimed in any of the preceding claims, further including means for preventing the pointer from sliding off the ruler.
7. A drawing tool as claimed in any of the preceding claims, wherein the pointer includes opfical magnifying means for magnifying readngs of the linear precision scale of the ruler.
8. A drawing tool as claimed in any of the preceding daims, further induding means for locking the pointer in position against movement relative to the ruler.
9. A drawing tool as claimed in any of the preceding daims, further induding means allowing insertion of at least one writing implement.
10. A drawing tool as claimed in any of the preceding claims, further including means for preventing the drawing tool proper from direct contact with the drawing surfaces.
11. A drawing tool as claimed in any of the preceding claims, wherein the protractor is approximately 2 cm in diameter and 2 mm in thickness.
12. A drawing tool as claimed in any of the preceding claims, wherein the ruler is approximately 1 cm in width, 11 cm in length and 2 mm in thickness.
13. A drawing tool as claimed in any of the preceding claims, wherein the pointer is approximately 1.4 cm in width, 3 cm in length and 4 mm in thickness.
14. A drawing tool as claimed in any of the preceding claims, further including means allowing drawing of a straight line along a central longitudinal axis of the ruler.
15. A drawing tool as claimed in any of the preceding claims, wherein the drawing tool is adapted to be used on paper, white board, black board, and other similar surfaces.
16. A drawing tool substantially as described herein with reference to and as illustrated in Figures 1 to 11 of the accompanying drawings.