GR20180100258A - Drawing instrument for mechanical designs - Google Patents

Abstract

Novelty: a drawing instrument for mechanical designs or for the modification of ordinary instruments is disclosed (fig.1,2). Technical features: compared to ordinary drawing instruments, the replacement of the empty ink cartridge 127 is achieved in the least possible time by pressing the two fingers on the surface 145 resulted upon increase of the length of the main drawing instrument 106, the empty cartridge 127 being held by other fingers ; the user is in position first to pull the drawing instrument 123 out of the empty cartridge and then to push it into the ink-filled cartridge 127. Advantages: simple construction, reduction of the construction cost and increase of the ink cartridge capacity.

Description

Mechanical drawing design tool.

The present invention relates to a new mechanical design drawing instrument in accordance with the main concept of patent claim 1 and more specifically to a modification of the construction of the body of a conventional drawing instrument, so that: (a) the replacement of the empty ink cartridge (127) is done only with the user's fingers and in the shortest possible time, (b) to produce a structurally simpler and lower-cost drawing instrument (Fig. 2) and (c) to produce a drawing instrument in which the ink cartridge (164) has a capacity of at least twice the capacity of the ink cartridge (110) of the conventional instrument.

The conventional mechanical drawing instrument is an instrument that writes on paper a line with a line thickness that is predetermined by its construction and is widely used by the vast majority of Engineers and mechanical and Civil Engineering drafters and is marketed by the ROTRING Company under the name RAPIDOGRAPH, without this meaning that the present invention is limited only to the drawing instrument of the ROTRING Company and excludes the application of the present invention to other conventional drawing instruments of the same or any other company, as it does not mean that it excludes the application of the present invention to the creation of an entirely new mechanical drawing design tool. This new design instrument is described in detail in the attached drawings.

The original purpose of the present invention was to find another more convenient, simpler and faster way to replace the empty ink cartridge and if possible to come up with a mechanical design drawing instrument with a simpler and less expensive construction. As described in the following paragraphs and pages all my goals were achieved.

As is known, in order for the user to replace the empty ink cartridge (110) in the conventional drawing instrument (Fig. 1) he must:

(a). Unscrew the Mantle (104) from the main drawing instrument (106).

(b). Unscrew from the ink cartridge (110) the outer casing (113) of the ink cartridge (110), which casing (113) consists of a tubular structure, at one end of which there is an internal thread (114), which it is screwed to the external thread (112) on the ink cartridge (110), while an internal thread (115) has been made at the other end of this tubular structure.

(c). Screw the internal thread (115) of the external casing (113) of the ink cartridge (110) to the external thread (108) of the main design tool (106).

(d) Pull the outer casing (113) of the ink cartridge (110) and with it the main drawing instrument (106) out of the empty ink cartridge (110).

(e) Wipe the ink covering the surface of the main drawing instrument (106) with a tissue.

(f) To push the outer casing (113) of the ink cartridge (110) and with it the main drawing instrument (106) into a filled ink cartridge (110) and (f). To unscrew the main drawing instrument from the internal thread (115) of the end of the casing (113) of the ink cartridge, so that the main drawing instrument is ready for use, after the user has first screwed the Cloak (104) back onto the instrument design (106) and the outer casing (113) of the ink cartridge (110) onto the ink cartridge (110).

The solution to this problem is achieved according to the invention by the features mentioned in Claim 1 and the remaining Claims.

In the mechanical drawing drawing instrument of the present invention, by increasing the length of the main drawing instrument (106) by 10 or 20 or even 30 millimeters, the surfaces (122) or (132) which the user can press with two fingers, while holding the empty ink cartridge (127) with two other fingers, to pull the main drawing instrument (123) out of the empty cartridge (127) and then push it into a full cartridge (127) of ink, so the user does not need to use the ink cartridge housing, which is screwed to the main drawing instrument to pull the main drawing instrument (106) out of the empty ink cartridge (110)

It is clear and self-evident that in the system of the present invention the user has the option to fill the empty ink cartridge (163 or 164) from an ink bottle, so he does not need to buy a new full ink cartridge, this is of course also done in conventional drawing instrument (Fig. 1), but the greater capacity of the new cartridge (163 or 164) facilitates this to be done more easily and at much longer intervals.

To make the difference in the replacement time of an empty ink cartridge in the conventional instrument and the design instrument of the present invention more clear, the following is mentioned.

In order to replace the empty ink cartridge (127) in the drawing instrument of the present invention, the user must:

(a) Unscrew the Mantle (119) from the main drawing instrument (123) and possibly unscrew the outer casing (126) of the ink cartridge (127) from the ink cartridge (127),

(b) To pull the outer casing (126) of the ink cartridge (127) and with it the main drawing instrument (123) out of the empty ink cartridge (127).

(c) Wipe the ink covering the surface of the main drawing instrument (106) with a tissue.

(d) To push the outer housing (113) of the ink cartridge (127) and with it the main drawing instrument (123) into a filled ink cartridge (127) and

(e) Screw both the Cloak (119) onto the drawing instrument (123) and the outer housing (126) of the ink cartridge (127) onto the ink cartridge (127) so that the main drawing instrument is ready to use.

An increase in the length of the body of the conventional main drawing instrument (106), i.e. an increase in length of 1 to 2 or even 3 centimeters will cause (a) an equal increase in the length of the Cloak (104), so that the Jacket (119) and (b) should be compensated with at least one of the following increases in length (b-1) increase in the length of the needle (139) (b-2) increase in the length of the piston (138), (b -3) increasing the length of the tube (155) of the cap (109) of Figure 15, so as to produce the tube (154) of the cap (109a) of Figure 20, (b-4) increasing the length proportionally or according to other specifications of all three aforementioned lengths, as will be explained in the next paragraph and (c) will also cause an increase in the length of the assembled drawing instrument of the present invention by one to at least three centimeters.

This increase in the overall length of the assembled drawing instrument of the present invention (a) offers nothing to the functionality of the drawing instrument, because the conventional drawing instrument has the ideal ergonomic length for a drawing instrument, and (b) would require changes in the dimensions of the packages as well of the design instrument, thus also an indirect additional increase in the cost of sale.

Accordingly, this increase in the overall length of the assembled plotter of the present invention can and should be avoided by an equal reduction in the length of the conventional ink cartridge cover (126) to produce the cartridge cover (134). (127) of the ink, because the length of the part of the ink cartridge (127) that enters into the conventional outer casing (126) of the cartridge is much shorter than the total length of the outer casing (126), so as shown in Fig. 2e the space (131) with a length of approximately four centimeters is available, which can easily be removed and the outer casing (134) of the ink cartridge can be obtained, as shown in Fig. 3e.

In the new mechanical design drawing instrument of the present invention (Fig. 2 and Fig. 3) the housing (126 or 134) has lost the most basic role it had in replacing the empty ink cartridge (127) and has become a simple decorative element , which well and for reasons of cost reduction can and should be eliminated by integrating it into the ink cartridge (163 or 164), an integration that also allows the cartridge (163) to store at least twice as much ink.

This increase in the length of the conventional main drawing member (106) will, of course, have an effect on the interior of the new main drawing member (123), because at least one of the lengths, the length of the needle (139 ) or the length of the piston (138) or the length of the tube (155) of the cap (109), or to increase proportionally or according to other specifications and all three of these lengths, as will be explained in the next paragraph.

Therefore, the new drawing instrument of the present invention (Fig. 2 or Fig. 3) differs from the conventional instrument (Fig. 1) in the following ways:

1) The main drawing instrument (123) is longer than the conventional main drawing instrument (106).

2) In the main drawing instrument (123), the external thread (108), present in the conventional drawing instrument (106), has been abolished.

3) The internal thread (115) in the housing (113) of the cartridge (110) has been replaced by a simple opening or hole (125a), simply to allow air to escape when the housing (126 or 134) is screwed into the cartridge (127) ), therefore the new design instrument also has a lower manufacturing cost.

4) The neon housing (134) of the ink cartridge (127) has a shorter length, in order to compensate for the increase in the length of the main drawing instrument (123) and not to unnecessarily increase the length of the assembled new drawing instrument of the present invention, while in the present invention it is even provided to abolish the casing (134) of the ink cartridge (127) by incorporating it into the ink cartridge (127) and

5) The new Cloak (119) is longer than the conventional Cloak (104).

Also, the new design instrument of the present invention (Fig. 2 or Fig. 3) has a lower manufacturing cost than the conventional instrument (Fig. 1) because:

(a) the external thread (108), present in the conventional drawing instrument (106), has been abolished;

(b) the housing (134) of the ink cartridge (127) has a shorter length, its internal thread (125) has been removed and replaced by a hole (125a), while it can also be completely removed by integrating it into the cartridge ( 163 or 164) of the ink,

(c) manufacturing piston (138a) is simpler and cheaper than manufacturing piston (138) and

(d) the cost of one cartridge (163 or 164) with three times the capacity of the conventional cartridge (110 or 127) is much less than the cost of three conventional cartridges (110 or 127).

Therefore, it has been proven that the detachment of the main drawing instrument (123) from the empty ink cartridge (127) is done comfortably and only with the use of the user's fingers, and thus a completely new drawing instrument is obtained, in which not only the replacement of an empty cartridge of ink is done in the minimum possible time, but also its manufacturing cost is significantly lower than the cost of a conventional drawing instrument (Fig. 1).

Sometimes in the conventional drawing instrument and if it has not been used for some time, the ink existing in the gap between the main drawing instrument (106) and the ink cartridge (110) dries up and the main drawing instrument (106) appears as if is stuck with the cartridge (110) and if the user tries to pull the ink cartridge housing (113) to which the main drawing instrument (106) is screwed, so that it comes out of the ink cartridge (110), then because more force is needed, the ejection is somewhat violent and uncontrolled, not excluding even ejection of ink droplets into the environment.

In order to exclude such an unfavorable situation in the neon drawing instrument as well (Fig. 2 or Fig. 3), before pulling the ink cartridge housing (126 or 134), the user must rotate the ink cartridge slightly and reciprocatingly around the body of the main drawing instrument to detach the cartridge from the stuck and dried ink residues in the body of the drawing instrument (123), so the detachment of the main drawing instrument (123) from the empty ink cartridge (127) is done with a simpler and more comfortably and with less force.

Brief description of the plans.

Fig. 1 shows a conventional drawing instrument disassembled and Fig. 2 and Fig. 3 show two drawing instruments according to the present invention.

Figure 4 shows in enlargement to better see the details of the construction of the main body (106) of the conventional drawing instrument shown in Figure 1c.

Fig. 5 shows a longitudinal section of the body of the main drawing instrument (106) of Fig. 4 with the pen (107).

Figure 6 shows the bottom view of the main design tool (106) of Figure 4 or Figure 5.

In Figure 7, Figure 8, Figure 9 and Figure 10, three embodiments of the present invention are shown, so as compared to Figure 4 to once again emphasize the differences between the conventional drawing instrument (Fig, 1) and the drawing instrument of the present invention (Fig. 2 and Fig. 3).

Figure 11 shows indicatively the bottom view of the main design tool (123) of Figure 10.

In Figure 12 and Figure 13 there is shown at the necessary magnification and without scale a section of a plotting instrument of the present invention, so as to show the manner in which the necessary amount of atmospheric air enters the ink cartridge to replace the volume of ink consumed.

Figure 14 shows a section of the plotter of Figure 13 along the line A-A simply to show the location of the notch (153) and without the location of the Sheath (119) being plotted.

Figure 15 shows an enlarged section of the body of the main drawing instrument (123) of an embodiment of the present invention in which to compensate for the increase in the length of the main drawing instrument (106) the length of the needle (139) has been increased, which is adapted to the piston (138), while it is possible to choose any desired length of the piston (138) and the cap (109) has the dimensions of the conventional drawing instrument or even any other dimensions desired by the designer of the present drawing instrument invention, such as e.g. the dimensions of (154) of the cap (109a) of Fig. 20.

In Figure 16 is shown a cross-section of the plotter (123) of the present invention of Figure 15 along the line BB.

In Figure 17 there is shown a cross-section of the plotter (123) of the present invention of Figure 15 along the line C-C.

Figure 18 shows an enlarged version of an alternative design of the slots (142) of Figure 5 in which a conical surface (156) is formed on the end of the piston (138) on which surface four fins (157) are fitted radially.

In Figure 19 there is shown a cross-section of the plotter (123) of the present invention of Figure 18 along the line D-D.

Figure 20 is an enlarged view of an alternative design of the main design tool of Figure 15 in which the piston (158) has a Y-shaped cross-section rather than a cylindrical rod cross-section like the piston (138) of Figure 15.

In Figure 21 is shown a cross-section of the plotter (123) of the present invention of Figure 20 along the line E-E.

In Figure 22 is shown a cross-section of the plotter (123) of the present invention of Figure 20 along line F-F.

In Figure 23 is shown a cross-section of the plotter (123) of the present invention of Figure 20 along the line G-G.

Figure 24 shows an enlarged side view of the piston (138a) of Figure 20.

Figure 25 shows a cross-section of the piston (138a) of Figure 24 along the line H-H.

Figure 26 shows the bottom view of the piston (138a) of Figure 24.

Fig. 27, Fig. 28 and Fig. 29 show a new ink cartridge (163) in which the housing (134) of the ink cartridge (127) has been incorporated.

Detailed description of the plans.

Preferred exemplary embodiments of the present invention are described below with reference to the figures.

Figure 1 includes Fig. 1a, Fig. 1b, Fig. 1c, Fig. 1d and Fig. 1e and shows a disassembled conventional drawing instrument, available on the market by the Rotring Company under the name Rapidograph, so that in comparison with the Fig. 2 and Fig. 3 make clear the differences between the conventional drawing instrument and the two drawing instruments of the present invention.

Fig. 1a shows the protection cover (100) of the pen (107), which protection cover (100) protects the pen (107) of the main drawing instrument (106) from possible impacts and when the cover is screwed or even adjusted on the Mantle (104) an airtight environment is created around the pen (107) of the main drawing instrument (106), in order to avoid as much as possible the drying of the ink inside the pen (107), while on the protective cover (100) the hook (101), which fixes the drawing instrument in the user's pocket, can optionally be fitted. Also in the protection cover (100) of the pen (107) an internal thread (102) has been made, which is screwed onto the external thread (103) of the front part of the drawing instrument or Mantle (104), so as to fix the protection cover (100) ) on the drawing instrument (106).

Fig. 1b shows the front part of the drawing instrument or Mantle (104), which when the drawing instrument is fully assembled partially covers the pen (107) and part of the end of the ink cartridge (110), in which Mantle (104 ) has been made on the one hand an external thread (103) on which the internal thread (102) of the protection cover (100) of the pen (107) is screwed and on the other hand in the lower part of the Mantle (104) an internal thread (105) ), which is screwed onto the external thread (111) of the ink cartridge (110).

Fig. 1c shows the main body (106) of the drawing instrument with the pen (107), in which the main body of the drawing instrument (106) has been made an external thread (108) onto which the internal thread (115) is screwed, which is constructed in the lower part of the outer casing (113) of the ink cartridge (110), so that the user of the drawing instrument can first pull the main body of the drawing instrument (106) out of an empty ink cartridge (110) and then pushing it into a filled ink cartridge (110), also shown is the cap (109), which seals the space (137).

Fig. 1d shows the ink cartridge (110), which supplies ink to the pen (107) of the main drawing instrument and contains a sufficient amount of ink, so that the designer does not need to add ink from time to time, and which cartridge has on the outer surface of two external threads, the external thread (111) on which is screwed during the assembly of the drawing instrument (106) the internal thread (105), which is present in the lower part of the front part of the drawing instrument or Mantle (104) and the external thread (112) onto which the internal thread (114) of the housing (113) of the ink cartridge (110) is screwed, while in the wall of the cartridge (110) there is also a small hole (127a). More manufacturing details of the cartridge (110) are shown in Figure 12 and Figure 13, where on the inner surface of the end of the cartridge (110) there is a spiral projection (150), which projection (150) cooperates with the wall of the drawing instrument creates a spiral conduit (151), which connects the hole (127a) in the wall of the cartridge with the two holes (123a and 123b) in the wall of the drawing instrument.

Fig. 1e shows the outer casing (113) of the ink cartridge (110), at its upper end there is an internal thread (114) into which the external thread (112) of the ink cartridge (110) is screwed, while at the lower end of the outer casing (113) of the cartridge there is an internal thread (115) into which the external thread (108) of the main drawing instrument (106) is screwed, so that the user of the drawing instrument can first pull the main body of the drawing instrument (106) out of an empty ink cartridge (110) and then push it into a full ink cartridge (110).

Figure 2 includes Figures 2a, Figure 2b, Figure 2c, Figure 2d and Figure 2e, and shows a disassembled plotting instrument of an application of the present invention, relating to the modification of the conventional Rapidograph plotting instrument proposed by the system of the present invention so that the replacement of the empty ink cartridge (127) is done using only the user's fingers.

Fig. 2a shows the protective cover (116) of the pen (107), to which is optionally fitted the hook (101), which secures the drawing instrument in the user's pocket. Also in the protection cover (116) of the pen (107) an internal thread (118) has been made, which is screwed onto the external thread (120) of the front part of the Mantle (119), so as to fix the protection cover (116) on the Cloak (119).

Fig. 2b shows the front part of the drawing instrument or Mantle (119), which Mantle (119) when the drawing instrument is fully assembled partially covers the pen (107) and part of the tip of the ink cartridge (127); in which Mantle (119) has been made on the one hand an external thread (120) on which the internal thread (118) of the protection cover (116) of the pen (107) is screwed and on the other hand in its lower part an internal thread ( 121), which is screwed onto the external thread (128) of the ink cartridge (127).

The total length of the Mantle (119) of Fig. 2b is greater than the Mantle (104) of Fig. 1b by a length approximately equal to the elongation of the main body of the drawing instrument (123), which was required for the creation of the surfaces (122 ) and (122a) of Fig. 2c and (132) of Fig. 3c.

Fig. 2c shows the modified according to the present invention main body (123) of the drawing instrument with the pen (107), in which main body (123) of the drawing instrument the flat surface (122) and the flat surface ( 122a) on the opposite side of the drawing instrument body, on which surfaces (122) and (122a) the user must press with his fingers to pull the main drawing instrument (123) from the empty cartridge (127).

It is clear and self-evident that the width of the parallel surfaces (122) and (122a) must be smaller than the outer diameter of the shell of the main design instrument (123) in that region, while the length of these surfaces can vary up to the minimum length necessary for the user to be able to use his fingers to pull it through the empty ink cartridge and this minimum length ranges from 1 to at least 2 or even 3 centimeters.

In Fig. 2c, the external thread (108) of Fig. 1c is not shown because it has been eliminated since there is no need to use the external casing (126) of the ink cartridge (127) to pull the main body of the drawing instrument out of the empty cartridge (127) of the ink and thus there the surface (133) is just a smooth surface, while in the lower part of the main body of the drawing instrument (123) of Fig. 2c there is the stopper (109), which seals a space, like the space (137) of Figure 5.

An extreme case of designing this new shell of the main design tool is for the shell to have more than one pair of parallel sides (122) and (122a) e.g. two or even three pairs of parallel sides, that is, the external shape of the cross-section of the shell of the main design instrument to be square or hexagonal. The choice of the number of parallel shell surfaces depends on what best serves the construction of the shell and which shape has the best manufacturing cost.

Fig. 2d shows the ink supply cartridge (127), which is exactly or the same as the cartridge (110), but with different numbers to avoid confusion, which cartridge (127) shows the external thread (128) on on which the internal thread (121), present at the bottom of the Mantle (119), is screwed during the assembly of the drawing instrument, as is also the external thread (129) on which the internal thread (130) of the casing is screwed ( 126) of the ink cartridge (127).

Fig. 2e shows the outer casing (126) of the ink cartridge (127), at the upper end of which there is an internal thread (130) into which the external thread (129) of the ink cartridge (127) is screwed, while in at the lower end of the outer casing (126) of the cartridge (127) there is an opening or hole (125a) for air to escape when the casing is screwed onto the cartridge.

Fig. 2e shows the outer casing (126) of the ink cartridge (127), which can be either the same as the casing (113) of the cartridge (110) of Fig. 1e, or slightly smaller than it, as the cover (134) of Fig. 3e in order to keep the overall length of the assembled new drawing instrument unchanged.

Fig. 2e also shows the space (131), which is an empty space, because the length of the cartridge (127), which enters the outer casing during assembly of the drawing instrument, is shorter than the length of the outer casing (126).

Because the extension of the length of the main drawing instrument (106) of Fig. 1c to create the surfaces (122) and (122a) of Fig. 2c increase the total length of the drawing instrument by a length of the order of three (3) centimeters , which would require changes even in the packaging box, the elimination of the space (131) and the reduction of the length of the outer casing makes it possible not to increase the overall length of the drawing instrument of the present invention.

Figure 3 includes Figures 3a, Figure 3b, Figure 3c, Figure 3d and Figure 3e, and shows an alternative design of the main design tool of the present invention in which instead of the two planes of parallel surfaces (122) and ( 122a) of Fig. 2c, on the cylindrical surface created by the extension of the length of the main drawing instrument, grooves or ridges (132) have been created, so as to increase the friction between the user's fingers and the shell of the main drawing instrument (123) , without the present invention excluding the other means, which increase the sliding friction of the fingers on the cylindrical surface such as bumps or protrusions or transverse grooves.

Fig. 1c also shows the hole (106a) in the wall of the main drawing instrument, which hole in Fig. 2c and Fig. 3c has the number (123a), through which the space (137) inside the drawing instrument is connected with the gap (150) of Fig. 12 between the drawing instrument body (104 or 123) and the inner surface of the ink cartridge (127), as shown in more detail in Fig. 4, Fig. 5, Fig. 12 and Fig. 13.

Figure 4 shows in enlargement to better see the details of the construction of the main body (106) of the conventional drawing instrument shown in Figure 1c.

Figure 4 shows the pen of the drawing instrument (107), the external thread (108) into which the internal thread (115) of the lower end of the casing (113) of the ink cartridge (110) of Fig. 1e is screwed, when the main drawing instrument (106) is to be extracted or inserted from the ink cartridge (110), the ring (135), which has the slot (135a) and the ring (136), which somehow seal the gap between the cartridge (110) and the main body (106) of the drawing instrument and the holes (106a) and (106b), through which holes the ink or the air that has entered the cartridge to replenish its volume escapes or returns of consumed ink, when the piston (138) of Fig. 5 reciprocates within the body of the main drawing instrument, when the user reciprocates the drawing instrument to continue the flow of ink through the pen (107).

Figure 4 also shows the cap (109), which seals the space (137) inside the body of the main drawing instrument (106), which cap (109) presents an opening (141) through which opening during operation it enters in the space (137) the ink contained in the cartridge (110), also in the cap (109) there is also the device (160) with which the cap (109) is locked onto the shell of the main drawing instrument (106) in a way so that it cannot be detached from the shell when the piston (138) hits the cap (109) during the reciprocating movements made by the user in order not to interrupt the flow of ink to the pen (107).

Fig. 5 shows a longitudinal section of the body of the main drawing instrument (106) of Fig. 4 with the pen (107), the external thread (108) onto which the internal thread (115) is screwed, which is made in bottom of the outer housing (113) of the ink cartridge (110), so that the user of the conventional drawing instrument can first pull the main body of the drawing instrument (106) out of an empty ink cartridge (110) and then push into a full ink cartridge (110), as also shown by the aforementioned holes (106a) and (106b), while between the piston (138) and the housing of the main drawing instrument (106) there is the gap (161).

When the user reciprocates both the conventional and the drawing instrument of the present invention mainly to restore an interrupted flow of ink, then within the space (137) reciprocates the piston (138) to the end of which the needle (139) is firmly attached ), which during reciprocating movements facilitates the flow of ink through the annular gap (140) between the needle (139) and the pen wall (107) away from the end of the pen (107) and possibly into from the gap (140) any dried ink residue that may be present there.

In Fig. 5 in the lower part of the main body of the drawing instrument (106) there is the cap (109) with the tube (155) attached to the cap, which seals the space (137) and the opening (141) through which opening ( 141) during operation, the ink contained in the cartridge (110) enters the space (137).

When the user uses the drawing instrument the piston (138) must not interrupt the flow of ink to the pen (107) for this reason the end of the piston (138), to which the needle (139) is attached, is shaped and presents notches (142) at the end of the piston (138) or alternatively through the gaps between the fins (157), which are fitted onto the conical surface (156) of Figure 18, so that in cooperation with the conically shaped wall of space (137a) at that point in the space (137), so that the flow of ink can not only continue even when, during the use of the drawing instrument, the pen (107) has a downward direction, so the piston (138) necessarily due to gravity it remains at the end of its reciprocating movement, but also to be able to escape the ink from the space (137a), when the piston (138) approaches the space (137a) during the reciprocating movements.

Here it should be noted that this outflow of ink from the space (137a), when the piston (138) approaches, must be done without developing that overpressure inside the space (137a), which would cause ink leakage from the tip of the pen (107).

An alternative design of the slots (142) is to have a conical surface (156) formed at the end of the piston (138) on which surface four fins (157) are fitted radially, as shown in detail in Figure 18.

On the surface of the conventional main design tool (104) and especially on the surface of the ring (135) at least one notch (135a) has been made, which notch in cooperation with the wall of the Mantle (104) creates an opening (151) through the through which opening the necessary supply of atmospheric air is introduced, which supply of air through the gap (152) between the drawing instrument and the Mantle (104) and through a hole (127a) in the wall of the cartridge (110) and through the spiral duct (150 ), which is generated between the cartridge (127) and the drawing instrument and through the two holes (123a and 123b) in the wall of the drawing instrument, ends up inside the ink cartridge to replenish the volume of the consumed ink inside the ink cartridge (127) and that no negative pressure is created inside the cartridge

On the surface of the main drawing instrument (123) of the present invention and because the ring (135) has a much increased length, the notch (135a) has been replaced by the notch (148) in the upper part of the main drawing instrument (123) which notch (148) participates in the transport of atmospheric air into the cartridge (127) in the manner described in the description of Fig. 12 and Fig. 13.

Fig. 4 and Fig. 6 also show the notch (135a) in the ring (135) through which in the conventional drawing instrument the necessary inflow of atmospheric air takes place to replenish the volume of the consumed ink, while in the drawing instrument of the present invention the corresponding notch is the notch (148), as analyzed in Fig. 13.

Figure 6 shows the bottom view of the main design tool (106) of Figure 4.

Figure 7, Figure 8, Figure 9, Figure 10 and Figure 11 show three embodiments of the present invention, so as compared to Figure 4 to once again emphasize the differences between the conventional drawing instrument and the drawing instrument of the present invention.

In Figure 7, the main drawing instrument of the present invention is shown enlarged, shown in Fig. 2c a drawing of the drawing instrument (123) of the present invention in which the length of the parallel planes of surfaces (122) and (122a), as well as of (144) and (144a) of Fig. 8, is such that the user, by pressing these surfaces with two fingers and the empty cartridge (127) with another two, can first detach the main drawing instrument (123) through the empty ink cartridge (127) and then push the main drawing device (123) into a full ink cartridge (127), also in the cap (109) there is also the device (160) with which the cap (109) locks onto the housing of the main drawing instrument (106) in such a way that it cannot be detached from the housing when the piston (138) strikes the cap (109) during the reciprocating movements made by the user to not to interrupt the flow of ink before s the pen (107).

Figure 8 shows an alternative design of the drawing tool (123) of the present invention of Figure 7 in which the cylindrical surface (145) of Figure 7 is longer than the length of surfaces (122) and (122a).

Figure 9 shows the bottom view of the main design tool (123) of Figure 7 and Figure 8.

Figure 10 shows an alternative design of the drawing tool (123) of the present invention in which the cylindrical surface (145) of Figure 8 instead of having the two parallel surfaces (144) and (144a) has the grooves (146), which increase the friction between the user's fingers and the surface of the drawing instrument body so that the user can either twist the drawing instrument body to free the nib (107) from the blocked internal thread of the cap (126) of the cartridge or even pull the drawing instrument (123) out of the empty cartridge (127), without the system of the present invention being limited to only a cylindrical surface (145) with grooves (146) and excluding in other applications the cylindrical surface (145) to present other equivalent means, which increase the friction between the user's fingers and the surface (145), such as e.g. many small bumps or small protrusions or small fins or even a very rough surface.

Figure 7, Figure 8 and Figure 10 also show the device (160) with which the cap (109) is locked onto the shell of the main design tool (106) in such a way that it cannot be detached from the shell, when the piston (138) hits the stopper (109) during the reciprocating movements made by the user so that the flow of ink to the pen (107) is not interrupted.

Figure 11 shows indicatively the bottom view of the main design tool (123) of Figure 10.

Figure 7, Figure 8, Figure 9, Figure 10 and Figure 11 also show the body of the main drawing instrument (123), the ring (136), the two holes (123) and (123a), which are the same as the holes (106a) and (106b) of Fig. 4, the cap (109), which seals the space (137) inside the drawing instrument as well as the opening (141) through which the ink flows into the space (137) , while the device (160) locks and secures the plug (109) on the housing of the main design instrument (123), so that the plug (109) remains attached to the housing (123) even when the piston (138) impacts forcefully upon it.

In Fig. 7, Fig. 8, Fig. 9, Fig. 10 and Fig. 11, the external thread (108) shown in Fig. 1c has not been made and the surface of the main drawing tool body in that area (147) is smooth and this is because the user no longer needs the intervention of the cartridge outer casing (126) or (134) to replace the empty ink cartridge, but can press the surfaces with his fingers and detach the main body of the drawing instrument from the empty cartridge and push it back into the full ink cartridge.

In Figure 10 the length of the surface with the grooves (146) can be of the order of 10 to 17 or even 30 millimeters in order to provide the user with sufficient contact surfaces and comfort of handling. According to the remaining characteristics there is no difference between Fig. 10 and Fig. 8 and Fig. 7.

A very important difference between Fig. 8 and Fig. 10 and Fig. 4 is that in the area (147) of the body surface of the drawing instrument (123) of Fig. 10 the external thread (108) has not been made. , shown in Fig. 4 and the surface of the body of the main drawing instrument in that area (147) is smooth and this is because the user no longer needs the mediation of the outer casing of the cartridge (113) to replace the clearance ink cartridge, but he can use his fingers to press the surfaces and detach the main body of the drawing instrument from the empty cartridge and push it back into the full ink cartridge.

In Figure 12 as well as in Figure 13, a cross-section of a plotting instrument of the present invention is shown at the necessary magnification to show how the necessary amount of atmospheric air enters the ink cartridge to replace the volume of ink consumed.

In Figure 12 as in Figure 13 and for the sake of simplifying the figures, both the piston (138) and the needle (139), which can move reciprocatingly in the space (137), have not been designed to keep the ink flow uninterrupted through the gap (140) of Figure 5.

In more detail, Figure 12 shows the cartridge (127) of the ink in which the lower end of the shell of the main drawing instrument is placed, such as the one shown with the number (123) of Figure 10 and with the cylindrical surface with the grooves ( 146), without this meaning that it limits the present invention and excludes in another application to use a design instrument of the present invention, as shown in Fig. 2c or in Fig. 3c or in Fig. 7, Fig. 8, Fig. 9, Fig. 10 and Figure 11.

Also shown in Figure 12 in dotted lines is the location of the Shroud (119), which surrounds the ink cartridge (127) and the internal thread (121) of the Shroud (119), which is screwed onto the external thread (128). of the ink cartridge (127).

Also shown in Figure 12 are dotted lines and the location of the ink cartridge housing (126) or (134) of the ink cartridge (127), which ink cartridge housing, may be as shown in Figure 2e with the number (126) or in Figure 3e with the number (134), while the internal thread (130) of the housing (126) or (134) appears to be screwed to the external thread (129) of the ink cartridge (127).

Figure 12 also shows the holes (123a) and (123b) in the body of the main design tool (123), which are the same as the holes (106a) and (106b) of Fig. 1c, Fig. 2g and Fig. 3c, as also the hole (127a) in the wall of the ink cartridge (127), while on the inner surface of the end of the ink cartridge (127) a spiral projection (150) has been made, which spiral projection (150) in cooperation with the surface of the shell of the main drawing instrument (123) creates a spiral duct (151), which spiral duct (151) connects the hole (127a) with the holes (123a) and (123b).

Also shown in Figure 12 is the ring (136), which closes the gap (153) between the Mantle (119) and the end of the cartridge (127) and thus allows the space of the holes (123a) and (123b) to communicate with the gap (153) only through the spiral duct (151) and the hole (127a) in the ink cartridge (127).

Figure 13 shows the rest of the section, shown in Figure 12 without the pen protective covers and without drawing the piston (138) and the needle (139) for the sake of simplification.

In Figure 13 is shown in dotted lines the position of the top of the Mantle (119), which surrounds the main drawing instrument (123) and causes it to remain stationary inside the ink cartridge (127), while leaving a small cylindrical gap (151) between the Mantle (119) and the body of the main drawing instrument (123) or any other main drawing instrument is provided by the present invention.

In Figure 13 on the front surface of the main drawing instrument (123) at least one notch of triangular cross-section (148) has been made and in fact the cross-section of the notch (148) preferably decreases as it approaches the axis of the main drawing instrument, so that through the gap ( 151) and the notch or slit (148) to allow atmospheric air to enter the gap (153) between the Mantle (119) and the body of the main design instrument (123), without the present invention being limited to this design of the notch (148) or only one notch and exclude any other notch with any equivalent plan or cross-sectional shape.

It is clear and self-evident that the flow of atmospheric air through the gap (153) is also facilitated by the construction of grooves, such as the grooves (146) of Figure 10 or the construction of the two parallel surfaces (122) and (122a) of Figure 7 or both (144) and (144a) of Figure 8.

The design consumption of any amount of ink from the ink, which the ink cartridge (127) contains, will create a small vacuum inside the cartridge, which through the holes (123a) and (123b), of the aforementioned spiral duct (151 ) and through the hole (127a) in the wall of the cartridge (127) will be transferred to the space of the gap (153) of Figures 12 and 13 between the inner wall of the Mantle (119) and the outer surface of the tip of the cartridge (127) of of ink, so due to this small gap, atmospheric air will be drawn through the gap (153) and notch (148) of Figure 13.

This facilitates a controlled introduction of atmospheric air into the ink cartridge to replenish the volume of ink consumed, while making it difficult for ink to leak from the ink cartridge into the environment, because any ink leakage must only be through the holes ( 123a) and (123b), the spiral duct (150) of the hole (127a), the gap (153), the notch (148) and the gap (151), since an ink leakage through the small gap (151) is almost impossible.

The design of the notch (148) is a modification of a corresponding notch (135a), which exists in the conventional design instrument in the ring (135) of Figure 4, a modification, which is necessary because in the design instrument of the present invention, the ring (135) has replaced by a cylindrical surface with grooves or even parallel surfaces and with a length of at least up to about two or three centimeters.

In Figure 13, the drawing instrument of the present invention is not equipped with an external thread, such as the external thread (108) of Figure 1c, so at that point the surface of the drawing instrument body (123) is a smooth cylindrical surface ( 147), as in Figure 10 and this is because the housing (113) of the ink cartridge (110) need not be used to extract the drawing instrument from the cartridge.

Figure 14 shows a section of the plotter of Figure 13 along the line A-A merely to show the location of the notch (148) and without the location of the Mantle (119) being plotted.

The system of the present invention proposes to increase the length of the main drawing instrument (106) and the Designer of the main drawing instrument of the present invention in order to compensate for the increase in the length of the main drawing instrument (123) has the opportunity to choose at least one of following changes (a) changing the length of the needle (139), (b) changing the length of the piston (138), (c) changing the length of the tube (154), which is fitted to the stopper (109a) and (d) change in length of all three proportionally.

In the system of the present invention, with the proposed changes, the length of the main drawing device (123), which enters into the ink cartridge (127), is not affected, so this length remains unchanged. The only case where a change in this length can occur is if the length of the piston (138a) of Figure 24 needs to be greatly increased, e.g. to ensure a working weight for the plunger (138a), so this length can be increased because the end of the main drawing member (123) in the assembled member is about 40 millimeters from the bottom of the ink cartridge (127).

Figure 15 shows an enlarged section of the body of the main drawing instrument (123) of an embodiment of the present invention, in which application to balance the increase in the length of the body of the drawing instrument (123) the length of the needle has been correspondingly increased ( 139), which is fitted to the piston (138).

Figure 15 also shows the Designer's ability to select any desired length of the piston (138), while the cap (109) with its attached tube (155) has the dimensions of a conventional design instrument, although it can to have any other dimensions desired by the designer of the design tool of the present invention, such as e.g. the tube (154) of the cap (109a) of Figure 20.

Figure 15 also shows the annular gap (161) between the piston (138) and the shell of the main drawing device (106), as well as the holes (123a and 123b), which, as shown in more detail in Figure 12, allow communication the space (137) with the spiral duct (150) between the cartridge (127) of the ink and the shell of the main drawing instrument (123).

In Figure 16 is shown a cross-section of the plotter (123) of the present invention of Figure 15 along the line BB.

In Figure 17 there is shown a cross-section of the plotter (123) of the present invention of Figure 15 along the line C-C.

Figure 18 shows an enlarged version of an alternative design of the slots (142) of Figure 5 in which a conical surface (156) is formed on the end of the piston (138) on which surface four fins (157) are fitted radially.

Figure 19 shows a cross-section of the plotter (123) of the present invention of Figure 18 along line D-D.

In the case where the increase in the length of the main design tool is chosen to be countered by the increase in the length of the piston (138), we notice that the distance of the space (137a) from the holes (123a) and (123b) increases greatly, with the result that when the piston (138) impinges on the conical wall of the space (137a) the flow of the amount of ink, expelled by the piston (138) from the space (137a), is forced to pass through the annular cross-sectional gap (161) between of the shell of the main design instrument (123) and the piston (138), which gap (161) has some length and where this flow will encounter relatively large resistances resulting in an overpressure in the space (137a) and perhaps a small outflow of ink from the end of the pen (107), an event that must be avoided at all costs or at least mitigated in duration and intensity.

Therefore, an attempt had to be made to reduce the amount of ink displaced by the piston (138) when during reciprocating movements the piston (138) moves through the ink, and the best way to achieve this is to reduce the frontal surface of the piston ( 138) during its movement in the ink and if it is possible to improve as much as possible the hydrodynamic characteristics of the new frontal surface of the new piston (138a).

Figure 20 shows in enlargement an alternative design of the main drawing instrument of Figure 15, made as a result of an attempt to reduce the resistances to the flow of the piston in the ink during the reciprocating movements, during which design the piston (138a) has a Y-shaped cross-section, and could even have a cross-shaped cross-section instead of the cylindrical rod cross-section, such as the piston (138) of Figure 15.

Also shown in Figure 20 is an alternative suggestion to balance at least part of the increase in the length of the body of the drawing instrument (123) with an increase in the length of the tube (154), which is adapted to the cap (109a).

Figure 20 shows the body (123) of the main drawing instrument, the pen (107), the needle (139) inside the pen (107), the notch (148), as well as the grooves (146), the cylindrical surface with the grooves (146), the two holes (123a) and (123b), the ring (136), the space (137), the plug (109a), which seals the space (137) inside the instrument, the opening (141) through which the ink flows into the space (137), the space (162) between the shell of the main drawing instrument (106) and the piston (138a) as well as the device (160), which locks and secures the neon plug (109a) to the housing of the main drawing instrument (123) so that the plug (109a) remains attached to the housing (123) even when the piston (138a) impinges on it.

It has sometimes been observed when using the conventional drawing instrument that when the flow is interrupted and the instrument does not write the user reciprocates the drawing instrument and then tries to write and does not write, then the user necessarily makes stronger or even more violent reciprocating movements , but then from the tip of the pen (107) an air-ink foam starts to come out for a few seconds, which indicates the existence of some small and temporary overpressure in the space (137a) of Figure 20.

During the reciprocating movements of the conventional drawing instrument, the piston (138) at one moment violently impacts the conical walls of the space (137a) displacing from the space (137a) a quantity of ink equal to the volume resulting from the product (Front surface of piston X stroke length), an amount of ink that must pass either through the annular cross-section of the gap (161), between the piston (138) and the inner head of the housing of the main drawing instrument (106), to finally diffuse into the space (137) or to pass through the holes (106a) and (106b) or (123a) and (123b) in the annular conduit (150) and through the hole (110a or 123a) in the space (153), as shown in more detail in Figure 12. Which path will be taken by the amount of ink leaving the space (137a) will depend on the resistances to flow presented by each path and on local conditions, e.g. dried ink residue in the ducts (153).

When the piston (138) of the conventional drawing instrument (106) impinges on the tube of the cap (109), then the amount of ink forced to leave the space (137) passes smoothly through the opening (141) of the cap ( 109) and diffuses into the ink cartridge (110).

In the case of the drawing instrument of the present invention, which has been chosen to compensate for the increase in the length of the main drawing instrument by lengthening the needle (139) of the piston (138), then nothing changes from what was mentioned above about the escape routes of the ink , which leaves the space (137a).

In the case of the drawing instrument of the present invention, which has been chosen to compensate for the increase in the length of the main drawing instrument by lengthening the piston (138), then the amount of ink forced to leave the space (137a) has only one escape path, i.e. to escape only through the gap (161) between the piston (138) and the inner surface of the shell of the main drawing instrument (123), a path, which has a relatively long length, i.e. from the space (137a) to the holes (123a) and (123b) of Figure 20, a path, which also translates into significant resistances to the flow of ink until this flow of ink escapes either through the tube (154) in the cartridge or also through the holes. (123a) and (123b).

It is obvious and self-evident that when the piston moves towards the pen (107) then some overpressure will be created in the space (137a) and when then some underpressure (vacuum) is removed and respectively the opposites occur in the space (137), which is next to the holes (123a) and (123b).

As a possible cause of the aforementioned outflow of ink foam and air from the tip of the pen (107) the underwriter of the present Description considers the intake of a small amount of air either through the slit (135a) or through the gap (140) between the needle (139) and of the pen (107) during particularly intense reciprocating movements.

Therefore, the greater the resistance to the flow of the piston (138) in the ink and the greater the resistances to the flow of the ink escaping from the space (137a) during the reciprocating movements, the greater the overpressure that will be created once in the space (137a) and the other time first inside the cartridge (110 or 127) of the ink.

But to reduce the resistance to the flow of the piston (138) in the ink the only feasible way is to reduce the frontal surface, which presents the piston (138) to the flow in the ink and thus the piston (138a) came to have a a Y-shaped cross-section or even a cross-shaped cross-section without excluding any other equivalent cross-sectional shape.

By way of example some dimensions are mentioned here, in the conventional main design instrument (106) the piston (138) has a diameter of 2.5 millimeters, its shell has an outer diameter of 5.0 millimeters and an inner diameter of 4.0 millimeters of the meter, so the annular cross-sectional gap (161) between the housing of the main design instrument (106) and the piston (138) presents an area of 7.7 square millimeters.

Illustratively mentioned here are some dimensions for the main drawing instrument (123) of the present invention, where the piston (138a) has a Y-section, formed by a body of 1.0 mm diameter with three fins of 0.2 mm thickness and length 1, 5 millimeters and a frontal surface of 3.03 square millimeters, so the gap (162) between the housing of the main drawing device (123) and the piston (138a) presents a surface of 9.6 square millimeters and therefore with the selection of the piston (138a ) with a Y cross-section the ink leakage area from 7.7 square millimeters of the gap (161) increased to 9.6 square millimeters of the gap (162), i.e. increased by about 25%.

The face of the 2.5mm diameter piston is 4.9 square millimeters, the face of the piston (138a) is about 3 square millimeters, so with this choice the face is reduced by about 38%, so the weight of a piston (138a) with a Y cross-section will be 38% less than the weight of a piston (138), when these two pistons are the same length. So for two pistons (138a) to have the same weight with a Y cross-section, the length of one must be greater by 60% of the length of the other.

With this reduction in piston cross-section, a piston weight issue may also arise if the length of the piston (138a) is kept equal to the length of the conventional piston (138), which is approximately 25 millimeters and any deficiency in weight of the plunger can be addressed by increasing the length of the plunger (138a), because the lengthening of the main drawing member (123) allows up to doubling the length of the plunger (138a).

In the system of the present invention, the Designer of the design instrument, if it is required that the neon piston (138a) has a length longer than the two lengths of the conventional piston, that is 2x25 = 50 millimeters then and as mentioned above, he has the possibility to increase the length as well of that portion of the main drawing instrument (123), which enters into the ink cartridge (134 or 163 or 164), because the distance of the end of the main drawing instrument (123), which enters into the ink cartridge (127) from the bottom of the cartridge (127) is about 34 millimeters, while this distance in the cartridges (163 and 164) will be even greater by 10 or even 20 millimeters.

By choosing the Y-section, the frontal surface of the piston was reduced by 38%, while the ink escape surface was increased by 25%.

In Figure 21 is shown a cross-section of the plotter (123) of the present invention of Figure 26 along the line EE.

In Figure 22 is shown a cross-section of the plotter (123) of the present invention of Figure 26 along the line F-F.

Figure 23 shows a cross-section of the drawing tool (123) of the present invention of Figure 26 along the line G-G and Figure 24 shows an enlarged side view of the piston (138a) of Figure 20.

Figure 25 shows a cross-section of the piston (138a) of Figure 24 along the line H-H. and Figure 26 shows the bottom view of the piston (138a) of Figure 24.

In Figure 27, Figure 28 and Figure 29 there is shown a change in the shape and size of the ink cartridge (127), a change, which comes as a necessary consequence of the changes in the use of the housing (113) of the ink cartridge (110), brought about by the present invention, in which changes the cartridge housing (110), which in the conventional drawing instrument is the most important tool for replacing an empty cartridge (110) with a full ink cartridge (110), in the neon drawing instrument of the present invention has become a mere decorative casing (126 or 134) of the ink cartridge (127), so it may well be eliminated by incorporating it into the ink cartridge (163).

The construction material of the new ink cartridge (163 or 164) can be the same relatively transparent construction material of the conventional ink cartridge (110) or any other transparent or opaque material with any color chosen for commercial reasons, even today with the transparent material most of the time you can't tell whether or not there is still ink inside the cartridge.

As can be understood by integrating the housing (134) into the cartridge (127) the wall of the housing (134) and the wall of the cartridge (127) are unified into one wall and thus the capacity of the cartridge (127) of ink is greatly increased, even and in the case that the length of the cartridge (163) with the integrated housing (134) remains the same as the length of the conventional ink cartridge (127), because the inner diameter of the ink space changes..

In more detail in Figure 27, an ink cartridge (127) and the housing (134) of the ink cartridge are shown in high magnification with dotted lines, so that it is easier to compare with Figure 28 and Figure 29.

In Figure 27, as in Figure 28 and Figure 29, the spiral projections (149) inside the tip of the ink cartridge (127) of Figure 12 have not been drawn only for the sake of simplification of Figure 27, since the incorporation of the housing ( 134) in the cartridge (127) has absolutely nothing to do with the spiral projections (149).

Figure 28 shows the new cartridge (163) in which the casing (134) of the ink cartridge has been incorporated so that the ink capacity of the ink cartridge can also be greatly increased, because the inner diameter of the ink cartridge (110 or 127) is about 7 millimeters, while the inner diameter of the new cartridge (163) with the integrated ink housing can be 9 millimeters, so the cross section of the ink cartridge is increased by 1.65 times.

In the conventional drawing instrument the distance from the tip of the pen (107) to the tip of the cartridge (110) is about 77 millimeters, and the distance of the tip of the pen (107) from the end of the cartridge housing (113) is 117 millimeters , which is also a correct ergonomic length for a mechanical design drawing instrument.

In the drawing instrument of the present invention the distance from the tip of the pen (107) to the tip of the cartridge (127) will be increased along the length of e.g. 20 millimeters, which increased the length of the main drawing instrument (123), i.e. the distance of the tip of the pen (107) from the end of the cartridge housing (134) integrated in the cartridge will be approximately 97 millimeters, while the total ergonomic length of drawing instrument must be 115 millimeters, so the length of the cartridge (163) with the integrated casing (134), must be increased by approximately 20 millimeters. Therefore the length of the cartridge (163) must be increased from 66 millimeters to 86 millimeters of the cartridge (164) to ensure the ergonomic length of the drawing instrument of 115 millimeters, without this limiting the present invention and excluding other lengths for the cartridge of ink.

It is clear and self-evident that the above applies only as long as the increase in the main body of the design instrument is 20 millimeters and that if this increase will not be 20 millimeters but 30 millimeters, then the new cartridge (164a) could still have and a length of 76 millimeters and not 86 millimeters, simply to maintain the ergonomic length of the drawing instrument at 115 millimeters, without excluding the Designer of the drawing instrument of the present invention from choosing any other length of the drawing instrument he wishes to any commercial or advertising specifications are met.

In Figure 28 the new ink cartridge (163) is the same length as the cartridge (110 or 127) about 65 millimeters, but to have the correct ergonomic length for an engineering drawing instrument, which the conventional drawing instrument also has, ie 115 millimeters, the neon drawing instrument with the housing integrated in the ink cartridge (113) must be increased by 20 millimeters the length of the cartridge (163) and in total the cartridge (164) has a length of 85 millimeters, as shown in Figure 29.

The ink storage space in the conventional cartridge (110 or 127) consists of a space with an inner diameter of about 6 millimeters and a length of 34 millimeters with a total capacity of about 1000 cubic millimeters.

The ink storage space in the cartridge (164) with its built-in housing of the present invention consists of a space of 8 mm internal diameter and 54 mm length with a total capacity of about 2700 cubic millimeters, that is, about 2.7 times the capacity of the conventional cartridge (110 or 127).

Although the foregoing description of the preferred embodiments of the present invention has been presented in drawings and descriptions with reference to specific embodiments and applications, which are presently preferred embodiments, it has been presented for illustrative and descriptive purposes and is not intended to be an exhaustive description, nor to be a limiting description of the specific embodiments and applications described, but instead is intended to cover all modifications and all equivalent and alternative forms that fall within the scope and spirit of the appended Claims.

Claims (7)

1. Mechanical design drawing instrument (Fig. 3), in order to quickly achieve the replacement of the empty ink cartridge (127) and a simpler and lower cost construction of it, which includes: - the main drawing instrument (123) with the pen (107), which in its interior includes a space (137), which is sealed with a plug (109), which plug with the device (160) locks the plug (109) onto the shell (123) and limits within the space (137) and the plunger (138) with the needle (139), which reciprocates inside the pen (107) when the user reciprocates the drawing instrument to keep the gap (140) clear and the ink flowing continuously to the pen, while the ink can flow through the slots (142) in the end of the piston (138) or alternatively through the gaps between the fins (157), from the space (137) to the space (137a) and vice versa, without to be affected by the position of the piston (138), - the device for sucking air into the cartridge (127) to replenish the volume of ink, which is consumed during use, which device includes the gap (151), the slot or notch (148), the grooves (146), the gap (153), the hole (127a), the spiral duct (150) and the holes (123a and 123b), leading through the space (137) and the opening (141) inside the cartridge (127), - the ink cartridge (127), which feeds the pen (107) and which cartridge (127) has an external thread (112) to screw there the internal thread (114) of the housing (113) and an external thread ( 111) for the Mantle (104) to be screwed there, while in the wall of the cartridge (127) there is also a small hole (127a) and on the inner surface of the end of the cartridge there is a spiral projection (149), which projection (149) in cooperation with the shell of the drawing instrument (123) creates a spiral duct (150), which connects the hole (127a) with the two holes (123a and 123b) in the wall of the drawing instrument (123), - the Mantle (119) , which surrounds the end part of the main drawing instrument (123) and the end of the ink cartridge (127), which Mantle (119) at its lower end has an internal thread (121) for screwing the Mantle onto the external thread (128) of the ink cartridge (127), while the Mantle (119) has an external thread ( 120), onto which the internal thread (118) of the protective cover (116) of the pen (107) is screwed, - the protective cover (116) of the pen, which both protects the pen and creates an airtight environment around the pen (107), - the outer casing (126) of the ink cartridge (127), at one end of which there is an internal thread (130), which is screwed onto the thread (129) of the ink cartridge (127), while at the other end there is an opening or hole (125a) for air to escape when the housing (126 or 134) is screwed onto the cartridge (127); which drawing instrument is characterized by a cylindrical surface (145) of suitable length, created at least by lengthening the part of the main drawing instrument (106), which does not enter into the ink cartridge (127), which cylindrical surface (145) has undergone a special treatment so that the user's fingers do not slip on the surface (145), so that the user of the drawing instrument pressing with his two fingers the surface (145), while with two others he presses the empty cartridge ink cartridge (127) to be able to first pull the main drawing instrument (123) out of the empty ink cartridge (127) and then push it into a full ink cartridge, thus reducing ink cartridge replacement time to a minimum possible. 2. A mechanical drawing drawing instrument as in Claim 1, characterized in that the increase in length of the main drawing instrument (106) is compensated within the main drawing instrument (123) by at least one of the following length increases (a) length increase of the piston (138), (b) increasing the length of the needle (139), (c) increasing the length of the tube (154), which is fitted to the cap (109a), and (d) increasing the length of all three of these lengths , according to the Designer's specifications, while apart from the main design tool (123) this increase also requires a corresponding increase in the length of the Mantle (119), while in order not to increase the total length of the assembled design tool, it is possible to reduce the length of the ink cartridge housing (126) to be the length of the ink cartridge housing (134). 3. An instrument for drawing a mechanical plan as in Claims 1 and 2, characterized in that the appropriate treatment of the cylindrical surface (145) is the construction in the body of the main drawing instrument (123) of one or more pairs of parallel plane surfaces (122 or 122a). 4. A mechanical design drawing instrument as in Claims 1 and 2, characterized in that the suitable treatment of the cylindrical surface (145) is to present means, which increase the friction in the movement of the user's fingers on the surface (145), which selected at least from one of the following categories grooves (146), or protrusions or bumps with suitable dimensions or even a strongly rough surface, so that the user can more comfortably and quickly detach the drawing instrument (123) from the clearance ink cartridge (127) and then push it into a full ink cartridge. 5. An instrument for designing a mechanical design according to one of the previous Claims, characterized in that the piston (138a) has a cross-section in the shape of a Y or a cross, so that the frontal surface presented by the piston (138a) when it moves reciprocatingly in the ink, when the user reciprocates the drawing instrument, while the reduction in the weight of the piston can be compensated by a significant increase in the length of the piston (138a), while by reducing the cross-section of the piston (138) the cross-section of gap (161) between the piston (138a) and the shell of the main drawing device (123), so the resistances to the flow of the amount of ink, which by advancing the piston (138) is expelled from the space (137a), are also reduced. 6. An instrument for drawing a mechanical drawing according to Claim 5 characterized by the extension of the part of the main drawing instrument, which enters into the cartridge (127) of the ink and enables the length of at least the piston (138a) with a Y-type cross-section or of the cross can be greater than 35 millimeters by up to at least 20 millimeters. 7. An instrument for drawing a mechanical plan according to one of the preceding Claims, characterized in that the housing (126 or 134) of the ink cartridge (127) has been removed by its integration into the wall of the ink cartridge (127), so that the cartridge (163) of the ink, the length of which may vary from a length equal to the length of the cartridge (127) to at least the length of the cartridge (164), which is 10 to 15 millimeters longer than the length of the conventional cartridge (127), so that the length of the assembled new drawing instrument is of the order of 115 millimeters, which is also the ergonomic length of a mechanical drawing drawing instrument, so the new ink cartridge (164) has almost three times the ink capacity of the cartridge ( 127), without excluding even longer ink cartridge lengths, if this is required by commercial or aesthetic specifications.