CN220447537U - Drawing ruler for constructional engineering - Google Patents

Abstract

The application discloses building engineering drawing ruler, including the blade, be provided with the scale on the blade, a plurality of breachs have been seted up to the scale along its extending direction equidistance, any the length of breach is 0.3mm-0.6mm, and the width is 0.2mm-0.4mm. According to the construction engineering drawing ruler, the scales are arranged on the ruler body, the plurality of notches are formed in the scales at equal intervals along the extending direction of the scales, so that the nib has a clamping sense when drawing, drawing staff can draw accurate line segments conveniently, and the size of any notch is smaller than that of the nib of a pencil, so that the nib is clamped due to the notch when drawing a drawing, drawing feedback is given to the drawing staff, the drawing staff can directly draw accurate line segments without repeatedly aligning the scale marks, drawing efficiency is improved, and meanwhile, the condition that the drawn line segments are 'wavy lines' due to the notches is avoided.

Description

Drawing ruler for constructional engineering

Technical Field

The utility model relates to the technical field of engineering drawing tools, in particular to a drawing ruler for constructional engineering.

Background

In building construction, engineering drawings not only can provide comprehensive and accurate references for constructors, but also can guide the constructors to conduct implementation of detail work, such as what standard each procedure should reach or what specification of building materials should be adopted. It can be seen that drawing a qualified, canonical engineering drawing is one of the skills each engineering designer must possess.

The applicant obtains following prior art through retrieving, specifically, publication number CN214295276U discloses a construction drawing ruler, including first chi board, the both ends of first chi board are all rotated respectively through pivot mechanism and are connected with second chi board and third chi board, the third chi board is rotated through pivot mechanism and is connected with the fourth chi board, the other end fixedly connected with slide of fourth chi board, the other end fixedly connected with slider of second chi board. The utility model is characterized in that the upper end of the ruler plate is provided with the first transverse ruler, the second transverse ruler is connected with the first transverse ruler in a sliding way, so that staff can draw straight lines and oblique lines during drawing, the second fixing column is connected with the second transverse ruler in a rotating way through the fourth ruler plate, the upper end of the second fixing column is fixedly connected with the first drawing circular plate, and the second drawing circular plate is connected with the first drawing circular plate in a sliding way, so that the staff can draw circles during drawing, the use of the staff is convenient, and the problem that the drawing ruler cannot be integrated in multiple functions is solved.

As can be seen from the above patent, although the architecture worker Cheng Zhitu ruler can realize the multifunctional integration of the drawing ruler, when drawing a drawing staff actually, the pen point needs to be manually aligned with the scale marks on each ruler plate, so that the drawing efficiency of the drawing staff is reduced. In addition, the scale on the current drawing rule usually takes 1cm as a unit length, if a long line segment is drawn, because the gap between adjacent scale lines is only 1mm, the drawing staff is easy to generate visual fatigue after drawing for a long time, and thus the situation of drawing wrong line segment size is easy to occur, so that the drawing size is inaccurate.

Disclosure of Invention

The utility model mainly aims to provide a construction drawing ruler, and aims to solve the problems that the existing construction drawing ruler is easy to reduce the drawing efficiency of drawing staff, and the drawing staff is easy to draw wrong line segment sizes after drawing for a long time, so that the drawing sizes are inaccurate.

In order to achieve the above purpose, the utility model provides a constructional engineering drawing ruler, which comprises a ruler body, wherein scales are arranged on the ruler body, a plurality of notches are formed in the scales at equal intervals along the extending direction of the scales, the length of any notch is 0.3mm-0.6mm, and the width of any notch is 0.2mm-0.4mm.

Preferably, the ruler body is provided with a first chute along the extending direction of the ruler body, a sliding block is slidably arranged in the first chute, a line drawing block for the pen point to be abutted is arranged at the bottom of the sliding block, a marking structure for aligning the scales is arranged at the top of the sliding block, the extending direction of the line drawing block is perpendicular to the extending direction of the first chute, and any side edge of the line drawing block is aligned with the marking structure.

Preferably, the second sliding groove is further formed in the ruler body along the extending direction of the ruler body, a connecting hole is formed in the position, corresponding to the second sliding groove, on the sliding block, a lock hole is formed in one side, facing the sliding block, of the line drawing block, the lock hole is coaxially arranged on the connecting hole, the size of the lock hole is consistent with that of the connecting hole, a locking piece is arranged on the sliding block, and the locking piece sequentially penetrates through the second sliding groove, the connecting hole and the lock hole are matched with the second sliding groove to lock the sliding block into the second sliding groove.

Preferably, the through hole for the nib to pass through is set up on the slider, the bottom at blade both ends all is formed with the location arch, two the location arch corresponds the scale mark setting at scale both ends, just the location arch with the central line parallel and level of first spout.

Preferably, the two ends of the ruler body are provided with grooves, any positioning component used for determining the position of the ruler body is arranged in each groove, each positioning component comprises an elastic piece, an end cover and a positioning column, two ends of each elastic piece are respectively connected with the end cover and the groove bottom of each groove, a through hole is formed in the groove bottom of each groove, one end of each positioning column penetrates through each through hole and is connected with the corresponding end cover through a fastener, and the other end of each positioning column is in tapered arrangement along the extending direction of each positioning column.

Preferably, the elastic piece is a spring, and limiting bosses for installing the spring are formed in the groove and on the end cover.

Preferably, a limit groove is formed in the position, which is away from one side of the end cover and corresponds to the through hole, on the ruler body, a flange for abutting with the bottom of the limit groove is formed on the outer wall of the positioning column.

Preferably, the end cover is detachably connected with a blocking cover, and the outer wall of the blocking cover stretches into the groove and is matched with the groove in a sliding contact mode.

The beneficial effects are that:

1. in the construction drawing ruler provided by the utility model, scales are arranged at the edge near the front side of the ruler body, and a plurality of notches are formed on the scales in a unit length of 1cm and at equal intervals along the left-right direction, namely, notches are formed on the scale marks of each centimeter on the ruler body. Further, when drawing a drawing staff, such as drawing a 15cm line segment, a notch is formed at the scale mark of 15cm, so that the pen point has a clamping sense when drawing to 15cm, and the drawing staff can draw an accurate line segment conveniently.

2. The pencil nib size for engineering drawing in the prior art is usually 0.5mm-1mm, and the length of any notch in the constructional engineering drawing ruler is 0.3mm-0.6mm and the width is 0.2mm-0.4mm, so that the size of the notch is smaller than the size of the pencil nib, thereby ensuring that the nib is blocked by the notch and gives drawing feedback to the drawing staff when drawing a drawing, enabling the drawing staff to directly draw an accurate line segment without repeatedly aligning scale marks, improving drawing efficiency, and simultaneously avoiding the condition that the drawn line segment is 'wavy line' due to the notch.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive faculty for a person skilled in the art.

FIG. 1 is a top view of a construction drawing scale according to one embodiment of the present utility model;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

FIG. 3 is an exploded view of a construction drawing ruler according to an embodiment of the present utility model;

FIG. 4 is a bottom view of an architectural engineering drawing scale according to an embodiment of the present utility model;

FIG. 5 is a cross-sectional view at B-B in FIG. 4;

FIG. 6 is a schematic view of the structure of a slider in a construction drawing ruler according to an embodiment of the present utility model;

FIG. 7 is a schematic view of a positioning column in a construction drawing scale according to an embodiment of the present utility model.

In the figure: 100-a drawing ruler for building engineering; 1-a blade; 2-notch; 3-a first chute; 4-a slider; 5-drawing line blocks; 6-identifying the structure; 7-a second chute; 8-connecting holes; 9-locking holes; 10-locking piece; 11-through holes; 12-grooves; 13-an elastic member; 14-end caps; 15-positioning columns; 16-via holes; 17-limiting bosses; 18-a limit groove; 19-flanges; 20-a baffle cover.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, which are generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, as provided in the accompanying drawings, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present application, it should be noted that, if the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like indicate an azimuth or a positional relationship based on that shown in the drawings, or an azimuth or a positional relationship that a product of the application conventionally puts in use, it is merely for convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element to be referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like in the description of the present application, if any, are used for distinguishing between the descriptions and not necessarily for indicating or implying a relative importance.

Furthermore, the terms "horizontal," "vertical," and the like in the description of the present application, if any, do not denote a requirement that the component be absolutely horizontal or overhang, but rather may be slightly inclined. As "horizontal" merely means that its direction is more horizontal than "vertical", and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present application, it should also be noted that, unless explicitly stated and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" should be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art in a specific context.

Example 1:

the present utility model proposes a construction drawing ruler 100.

In an embodiment of the present utility model, the construction drawing ruler 100 includes a ruler body 1, scales are provided on the ruler body 1, a plurality of notches 2 are equidistantly provided on the scales along the extending direction of the scales, the length of any notch 2 is 0.3mm-0.6mm, and the width is 0.2mm-0.4mm.

Specifically, in the construction drawing ruler 100 provided by the utility model, scales are arranged at the edge near the front side of the ruler body 1, and a plurality of notches 2 are formed on the scales in a unit length of 1cm at equal intervals along the left-right direction, namely, the notch 2 is formed at the scale mark of each centimeter on the ruler body 1, and the notch 2 is formed at the scale mark of 1cm and the scale mark of 2cm as shown in fig. 2. Further, when drawing a drawing staff, for example, drawing a 15cm line segment, a notch 2 is formed at the scale line of 15cm, so that the pen point has a clamping sense when drawing to 15cm, and the drawing staff can draw an accurate line segment conveniently.

It can be understood that the pencil nib size used for engineering drawing in the prior art is usually 0.5mm-1mm, and in the construction engineering drawing ruler 100 of the utility model, the length of any notch 2 is 0.3mm-0.6mm, and the width is 0.2mm-0.4mm, namely, the distance of any notch 2 along the left-right direction is 0.5mm-0.8mm, and the distance along the front-back direction is 0.2mm-0.4mm, so that the size of the notch 2 is smaller than the size of the pencil nib, thereby not only ensuring that the nib can be blocked by the notch 2 and give drawing feedback to the drawing personnel when drawing the drawing, enabling the drawing personnel to directly draw accurate line segments without repeatedly aligning the scale marks, improving the drawing efficiency, but also avoiding the situation that the drawn line segments are 'wavy lines' due to the notch 2.

Compared with the prior art, the construction engineering drawing ruler 100 has the advantages that scales are arranged on the ruler body 1, and the scales are provided with the plurality of notches 2 at equal intervals along the extending direction of the scales, so that a nib can feel stuck during drawing, drawing of accurate line segments by drawing staff is facilitated, and because the size of any notch 2 is smaller than that of a pencil nib, the nib can be stuck due to the notch 2 and give drawing feedback to the drawing staff when drawing a drawing, the drawing staff can directly draw accurate line segments without repeatedly aligning the nib with scale marks, drawing efficiency is improved, and meanwhile the condition that the drawn line segments are 'wavy lines' due to the notches 2 is avoided.

In an embodiment, a first chute 3 is provided on the ruler body 1 along the extending direction thereof, a sliding block 4 is slidably provided in the first chute 3, a line drawing block 5 for the pen point to abut is provided at the bottom of the sliding block 4, a marking structure 6 for aligning with the scale is provided at the top of the sliding block 4, the extending direction of the line drawing block 5 is perpendicular to the extending direction of the first chute 3, and any side edge of the line drawing block 5 is aligned with the marking structure 6.

Specifically, as shown in fig. 1 to 4, since the first chute 3 is opened on the rule body 1 along the left-right direction, and the slider 4 is provided in the first chute 3, the slider 4 is in sliding contact with the first chute 3 and can slide along the left-right direction, the bottom of the slider 4 is provided with the marking block 5 for the nib to abut against, and the top of the slider 4 is provided with the marking structure 6 for aligning the scale, the extending direction of the marking block 5 is the front-back direction and is perpendicular to the extending direction of the first chute 3, when the drawing staff needs to draw parallel lines or equidistant lines, the drawing staff slides the slider 4 and aligns the marking structure 6 on the top thereof with the scale lines, and the marking block 5 slides synchronously under the driving of the slider 4, at this time, the drawing staff can draw a reference line through the marking block 5, and slide the slider 4 again after the drawing of the reference line is completed, the marking structure 6 is aligned with the scale line of the target distance on the rule body 1, and simultaneously the marking block 5 is drawn again through the marking block 5 with the parallel line segments, thereby two parallel lines or equidistant lines are completed, the drawing is simple and flexible, and the drawing scope of the utility model is also enlarged, and the drawing scope of the drawing staff 100 is easy to use.

Further, since the extending direction of the line drawing block 5 is perpendicular to the extending direction of the first chute 3, the line drawing block 5 and the ruler body 1 are in a mutually perpendicular state in the same horizontal plane, so that a plotter can draw two mutually perpendicular line segments through the line drawing block 5 and the ruler body 1, and the application range of the constructional engineering drawing ruler 100 is further widened.

It can be appreciated that the marking structure 6 can adopt a pointer in the prior art, and the pointer is arranged at the top of the sliding block 4 and is used for pointing to the scale mark, so that a plotter can observe the moving distance of the sliding block 4 conveniently, and drawing parallel lines and equidistant lines with different pitches can be facilitated; meanwhile, in order to save cost and simplify the structure, an arrow, a polygonal block or a transverse line and the like can be directly stuck or formed on the top of the sliding block 4, namely, the arrow points to the scale line, any vertex of the polygonal block points to the scale line, the transverse line is flush with the scale line and other modes for pointing to the scale line, and the like, so that the same beneficial effects as the pointer can be generated, as shown in fig. 6, the identification structure 6 is a triangle structure formed on the top of the sliding block 4, and one vertex of the triangle points to the scale line.

It should be noted that, as shown in fig. 1 and 3, a zero scale line is further formed on the top surface of the rule body 1 near the second chute 7, a notch 2 is formed at the zero scale line, and another marking structure 6 is further disposed on the top of the slider 4, where the marking structure 6 is used for pointing to the zero scale line, so that a plotter can conveniently draw the datum line in two parallel lines or equidistant lines.

In an embodiment, the second sliding groove 7 is further formed in the ruler body 1 along the extending direction of the ruler body, the connecting hole 8 is formed in the position, corresponding to the second sliding groove 7, on the sliding block 4, the locking hole 9 is formed in one side, facing the sliding block 4, of the line drawing block 5, the locking hole 9 and the connecting hole 8 are coaxially arranged, the size of the locking hole is consistent with that of the locking hole 8, the locking piece 10 is arranged on the sliding block 4, and the locking piece 10 sequentially penetrates through the second sliding groove 7 and the connecting hole 8 and is matched with the locking hole 9 to lock the sliding block 4 into the second sliding groove 7.

Specifically, as shown in fig. 1 to 6, since the second chute 7 is provided on the blade 1 along the left-right direction, and the connecting hole 8 is provided on the slider 4 corresponding to the position of the second chute 7, the lock hole 9 is provided on the top surface of the line drawing block 5, the lock hole 9 can be provided as a threaded hole, the lock hole 9 is coaxially provided with the connecting hole 8 and has the same size, the slider 4 is provided with the locking member 10, the locking member 10 can be a set screw in the prior art, after the drawing staff moves the slider 4 in place, the slider 4 can be fixed in the chute through the threaded fit of the locking member 10 and the lock hole 9, thereby avoiding the line drawing block 5 from driving the slider 4 to slide when drawing a line segment, facilitating drawing, and being reliable in use.

It can be appreciated that when the set screw is loosened, the line drawing block 5 can rotate relative to the sliding block 4, so that the line drawing block 5 can be rotated to the bottom of the ruler body 1, thereby having the effect of rotating and storing the line drawing block 5, avoiding the line drawing block 5 from scratching drawing staff in the process of taking, preventing the line drawing block 5 from being damaged due to being always positioned outside the ruler body 1, and further enabling the appearance of the constructional engineering drawing ruler 100 to be more attractive.

In an embodiment, the slider 4 is provided with a through hole 11 for the nib to pass through, positioning protrusions are formed at the bottoms of the two ends of the ruler body 1, the two positioning protrusions are arranged corresponding to scale marks at the two ends of the scale, and the positioning protrusions are flush with the central line of the first chute 3. Specifically, when a plotter needs to draw a circle, the plotter passes a pen point through the through hole 11 on the slide block 4 and presses any one of the left end and the right end of the ruler body 1, and the plotter rotates the ruler body 1 by taking a positioning bulge at any one end of the bottom of the ruler body 1 as a fixed point, so that the drawing of the circle can be realized by taking the pen point as a moving point, and the practicability of the constructional engineering drawing ruler 100 is improved. Understandably, when the sliding block 4 is slid, the alignment condition of the mark structure 6 and the scale marks is checked, so that the center of the through hole 11 on the sliding block 4 is aligned with the scale marks, and circles with different sizes are drawn by matching with the pen point, and the use is flexible and convenient; meanwhile, the sliding block 4 is fixed in the sliding groove through the locking piece 10, so that the sliding block 4 is prevented from sliding randomly in the drawing process, and the use is reliable.

In another embodiment, the two ends of the rule 1 are provided with grooves 12, a positioning component for determining the position of the rule 1 is arranged in any groove 12, the positioning component comprises an elastic piece 13, an end cover 14 and a positioning column 15, two ends of the elastic piece 13 are respectively connected with the end cover 14 and the bottom of the groove 12, a through hole 16 is formed in the bottom of the groove 12, one end of the positioning column 15 penetrates through the through hole 16 and is connected with the end cover 14 through a fastener, and the other end of the positioning column 15 is gradually reduced along the extending direction of the positioning column.

Specifically, as shown in fig. 1 to 3, the left end and the right end of the rule body 1 are both provided with grooves 12, the lower end of an elastic member 13 in the positioning assembly is connected with the bottom of the grooves 12, the upper end of the elastic member 13 is connected with an end cover 14, the bottom of the grooves 12 is provided with a through hole 16, the upper end of a positioning column 15 passes through the through hole 16 and is connected with the end cover 14 through a fastener, the fastener can also be a set screw in the prior art, the end cover 14 is provided with a mounting hole, the upper end of the positioning column 15 is provided with a threaded hole, the set screw passes through the mounting hole and is in threaded fit with the threaded hole on the positioning column 15 to realize the mounting of the positioning column 15, and the positioning column 15 can slide up and down in the through hole 16 relative to the rule body 1.

Further, the end cover 14 always keeps the positioning column 15 in the through hole 16 under the action of the elastic piece 13, and the lower end of the positioning column 15 does not exceed the bottom surface of the ruler body 1, so that the ruler body 1 can be stably placed on a drawing sheet, and drawing staff can draw line segments conveniently. It can be appreciated that when the drawing of a circle is needed, the drawing staff presses the end cover 14 to enable the lower end of the positioning column 15 to extend out to the bottom surface of the ruler body 1 and to be abutted to the surface of the drawing paper, and then the positioning column 15 can be used as a fixed point to draw the circle in cooperation with the pen point penetrating through the sliding block 4, so that the structural design is ingenious and reasonable. In addition, the lower end of the positioning post 15 is tapered along the up-down direction, so that the positioning post 15 is fixed on the drawing sheet.

In one embodiment, as shown in fig. 3 and 5, the elastic member 13 is a spring, and a limiting boss 17 for installing the spring is formed in the groove 12 and on the end cover 14. It can be understood that the elastic member 13 is a spring, and the spring has the characteristics of compact structure, easy material taking and large elastic deformation force, so that the end cover 14 is convenient to jack up and the positioning column 15 is always kept in the through hole 16, meanwhile, the limiting boss 17 for installing the spring is formed at the bottom of the groove 12 and below the end cover 14, so that the spring is prevented from running in the pressing and rebounding processes, and the comfort and stability of the pressing end cover 14 are improved.

In an embodiment, as shown in fig. 3, 4, 5 and 7, a limit groove 18 is formed on the side, away from the end cover 14, of the blade 1 and corresponding to the position of the through hole 16, and a flange 19 for abutting against the bottom of the limit groove 18 is formed on the outer wall of the positioning column 15, so that the end cover 14 is prevented from being ejected out of the groove 12 due to excessive elastic restoring force in the spring rebound process, namely, the flange 19 and the bottom of the limit groove 18 can play a limiting role in the up-down direction on the positioning column 15, and the structural design is simple and reasonable.

In one embodiment, the end cap 14 has a retaining cap 20 removably attached thereto, with the outer wall of the retaining cap 20 extending into the recess 12 and in sliding contact engagement with the recess 12. As can be appreciated, as shown in fig. 1 and 3, by forming mutually matched threads on the outer wall of the end cover 14 and the inner wall of the baffle cover 20, the detachable connection between the end cover 14 and the baffle cover 20 is realized, and the outer wall of the baffle cover 20 extends into the groove 12 and is matched with the groove 12 in a sliding contact manner, so that the positioning assembly can be completely shielded, and not only is the difficulty in pressing the end cover 14 caused by entering foreign matters in the groove 12 avoided, but also the appearance is more attractive and normative.

In another embodiment, the outer wall of the end cover 14 is in sliding contact fit with the wall of the groove 12, so that the baffle cover 20 is not required to be additionally arranged, the structure is simplified, and the cost is saved.

The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the same, but rather, various modifications and variations may be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims (8)

1. The utility model provides a building engineering drawing ruler, includes blade (1), be provided with the scale on blade (1), its characterized in that, a plurality of breach (2) have been seted up to the scale along its extending direction equidistance, arbitrary the length of breach (2) is 0.3mm-0.6mm, and the width is 0.2mm-0.4mm.

2. The constructional engineering drawing ruler according to claim 1, wherein a first chute (3) is formed in the ruler body (1) along the extending direction of the ruler body, a sliding block (4) is slidably arranged in the first chute (3), a line drawing block (5) for enabling a pen point to abut against is arranged at the bottom of the sliding block (4), a marking structure (6) for aligning scales is arranged at the top of the sliding block (4), the extending direction of the line drawing block (5) is perpendicular to the extending direction of the first chute (3), and any side edge of the line drawing block (5) is aligned with the marking structure (6).

3. The building engineering drawing ruler according to claim 2, wherein a second sliding groove (7) is further formed in the ruler body (1) along the extending direction of the ruler body, a connecting hole (8) is formed in the position, corresponding to the second sliding groove (7), of the sliding block (4), a lock hole (9) is formed in one side, facing the sliding block (4), of the line drawing block (5), the lock hole (9) is coaxially arranged with the connecting hole (8) and is consistent in size, a locking piece (10) is arranged on the sliding block (4), and the locking piece (10) sequentially penetrates through the second sliding groove (7) and the connecting hole (8) and is matched with the lock hole (9) to lock the sliding block (4) into the second sliding groove (7).

4. A drawing ruler for constructional engineering according to claim 3, wherein the sliding block (4) is provided with a through hole (11) for a pen point to pass through, positioning protrusions are formed at the bottoms of two ends of the ruler body (1), two positioning protrusions are arranged corresponding to scale marks at two ends of the scale, and the positioning protrusions are flush with the central line of the first sliding groove.

5. A construction drawing ruler according to claim 3, wherein grooves (12) are formed in two ends of the ruler body (1), positioning components used for determining the position of the ruler body (1) are arranged in any groove (12), each positioning component comprises an elastic piece (13), an end cover (14) and a positioning column (15), two ends of each elastic piece (13) are respectively connected with the end cover (14) and the groove bottom of the corresponding groove (12), through holes (16) are formed in the groove bottom of the corresponding groove (12), one end of each positioning column (15) penetrates through each through hole (16) and is connected with the corresponding end cover (14) through a fastener, and the other end of each positioning column (15) is in tapered arrangement along the extending direction of the corresponding positioning column.

6. The construction drawing ruler according to claim 5, wherein the elastic piece (13) is a spring, and limiting bosses (17) for installing the spring are formed in the groove (12) and on the end cover (14).

7. The constructional engineering drawing ruler according to claim 6, wherein a limit groove (18) is formed in the ruler body (1) at a position which is away from one side of the end cover (14) and corresponds to the through hole (16), and a flange (19) used for being abutted with the bottom of the limit groove (18) is formed on the outer wall of the positioning column (15).

8. The construction drawing ruler according to claim 7, wherein a blocking cover (20) is detachably connected to the end cover (14), and the outer wall of the blocking cover (20) extends into the groove (12) and is in sliding contact fit with the groove (12).