A ruler for blood drop impact angle inference

Abstract

The utility model relates to the technical field of tool ruler for blood drop impact angle inference, especially a tool ruler for blood drop impact angle inference, which relates to the technical scheme that includes: measuring scale, is equipped with measuring area and contrast area on the measuring scale, the measuring area includes the scale that is distributed in the four around measuring scale, the maximum length of scale is 28cm, the minimum unit of scale is 1mm, the contrast area includes multiple contrast holes that are uniformly distributed on the measuring scale and are different in size and shape, multiple contrast holes are arranged in a 6*6 layout, and the measuring scale is located on one side of the edge contrast hole and is marked with angle indication and speed indication. The utility model can improve the efficiency of on-site blood analysis, can be used independently, and can also be used together with various tools or technical methods. It plays a very important role in the analysis of the crime process, the reconstruction of the crime scene and the determination of the investigation direction.

Description

Technical Field

[0001] This utility model relates to the field of tool rulers for inferring the impact angle of blood droplets, and in particular to a tool ruler for inferring the impact angle of blood droplets. Background Technology

[0002] Bloodstains are a common piece of physical evidence at crime scenes, including assault and homicide cases. Rapid analysis of bloodstains at the scene aids in case reconstruction and investigation. Based on the different morphological differences caused by the angle of impact between the blood droplet and the target surface, bloodstains can be classified into two types: perpendicular impact and non-perpendicular impact. When a blood droplet impacts the target surface at a 90° angle, a circular bloodstain is formed. When the inner angle of the blood droplet impacts the target surface is acute, the lower part of the blood droplet contacts the target surface first, while the upper part, which has not yet stabilized, continues to move along its original direction due to inertia, forming an elliptical bloodstain. The smaller the impact angle, the greater the stretching of the bloodstain, the smaller its width, and the greater its length.

[0003] In crime scene investigation, the impact angle of blood droplets can be calculated based on the shape of the bloodstains. This impact angle can be used to infer the horizontal velocity of the blood droplets, indicating the speed of the bleeding person or blood-stained object, and can also help locate the source of the blood and reconstruct the crime scene. The conventional method for inferring the impact angle is to measure the length and width of the bloodstain, calculate the width-to-length ratio, and then calculate the arcsine function of that ratio to obtain the impact angle. This method requires not only professional bloodstain analysis knowledge from the investigators but also precise measurement and calculation skills. Especially at crime scenes with large amounts of blood, the subsequent measurement and calculation significantly increases the workload and time-consuming process, hindering rapid analysis and judgment of the scene. Currently, there is no analytical tool for quickly inferring the impact angle of blood droplets. Utility Model Content

[0004] The purpose of this invention is to address the problems existing in the background technology by proposing a special tool for on-site bloodstain angle analysis, specifically a tool ruler for inferring the impact angle of blood droplets.

[0005] The technical solution of this utility model: a tool ruler for inferring the impact angle of a blood droplet, including a measuring ruler, the measuring ruler having a measuring area and a comparison area, the measuring area including a scale distributed around the measuring ruler, the maximum length of the scale being 28cm, the minimum unit of the scale being 1mm, the comparison area including multiple comparison holes evenly distributed on the measuring ruler and having different sizes and shapes, the multiple comparison holes being arranged in a 6*6 layout, the measuring ruler (1) and the side of the edge comparison hole being marked with angle and speed readings;

[0006] Two measuring pens are placed on one side of a measuring ruler, and the two measuring pens measure the width and length of the bloodstain, respectively.

[0007] A coordinate positioning mechanism is installed on the measuring ruler, which positions the corresponding comparison hole on the measuring ruler based on the data measured by the measuring pen.

[0008] Optionally, the coordinate positioning mechanism includes a drive groove and a slide groove disposed on the four sides of the measuring ruler. The slide groove is located above the drive groove and communicates with the surface of the measuring ruler. A magnetic sealing block is slidably installed in the drive groove, and a designated block that moves synchronously with the magnetic sealing block is slidably installed in the slide groove.

[0009] Optionally, the magnetic sealing block includes a first magnetic block that is slidably installed in the drive groove, sealing blocks are fixedly installed on both sides of the first magnetic block, and a first sealing ring is fixedly installed around the sealing block.

[0010] Optionally, the designated block includes a second magnetic block that is slidably installed in the groove, with support wheels rotatably installed on both sides of the second magnetic block, and a support block fixedly installed on the second magnetic block, the support block extending above the surface of the measuring scale.

[0011] Optionally, a first indicator line is fixedly installed between the support blocks in the two horizontally arranged slides, and a second indicator line is fixedly installed between the support blocks in the two vertically arranged slides, wherein the first indicator line and the second indicator line are perpendicular to each other.

[0012] Optionally, the measuring pen includes a cylinder, in which a sealing block and a measuring rod are slidably installed. A second sealing ring is fixedly installed around the sealing block. Scale lines are engraved on the measuring rod. The sealing block and the measuring rod are fixedly connected. A pull rod is fixedly installed on the sealing block. The pull rod observes one side of the cylinder and extends to the outside of the cylinder. An identification plate is provided on the surface of the cylinder.

[0013] Optionally, a first connecting pipe is fixedly installed on both sides of the two horizontally arranged drive slots, a second connecting pipe is fixedly installed on both sides of the two vertically arranged drive slots, and a conveying pipe is fixedly installed on both sides of the cylinder. Two conveying pipes on one cylinder are fixedly connected to two first connecting pipes respectively, and two conveying pipes on the other cylinder are fixedly connected to two second connecting pipes respectively.

[0014] Optionally, the cylinder, the first connecting pipe, the second connecting pipe, the conveying pipe, and the drive groove are all filled with a transmission medium.

[0015] In summary, this application includes at least one of the following beneficial technical effects:

[0016] This tool is designed to integrate multiple functions such as physical evidence measurement, angle inference, and speed / height estimation. It can quickly compare bloodstains at bloodshed scenes and obtain results directly on-site, eliminating the tedious steps of measuring bloodstains and then calculating them. This can greatly save time in reconstructing crime scenes using bloodstain analysis technology and improve the efficiency of case analysis and judgment.

[0017] This tool is easy to use and simple to operate. It does not require surveyors to have extensive theoretical knowledge and practical experience. Only a simple introduction is needed to operate it. It has a low barrier to entry and is widely applicable, which can greatly promote the popularization of bloodstain angle analysis technology.

[0018] This tool is designed based on a large amount of experimental data and is highly scientific. Using this tool can reduce analytical errors caused by subjective judgment, reduce misjudgments of investigation direction due to empiricism, and improve the accuracy and reliability of inferring the angle of bloodstains at the scene.

[0019] This tool is easy to operate and carry, making it suitable for practical use by frontline police investigators. Furthermore, the tool is simple to manufacture, inexpensive, and easy to promote.

[0020] In summary, this invention can improve the efficiency of bloodstain analysis at crime scenes. It can be used independently or in conjunction with various tools or techniques. It plays a crucial role in analyzing the crime process, reconstructing crime scenes, and clarifying the direction of investigations. Attached Figure Description

[0021] Figure 1 This is a schematic diagram showing the connection relationship of the delivery pipes;

[0022] Figure 2 This is a schematic diagram of the coordinate positioning mechanism;

[0023] Figure 3 This is a schematic diagram showing the positions of the first connecting pipe and the second connecting pipe;

[0024] Figure 4 This is a schematic diagram of the internal structure of the measuring pen;

[0025] Figure 5 for Figure 2 A magnified view of a section at point A in the middle;

[0026] Figure 6 for Figure 2 A magnified view of a section at point B in the middle;

[0027] Figure 7 A detailed schematic diagram of a ruler for measuring the angle of bloodstains on glass;

[0028] Figure 8 A detailed diagram of a ruler for measuring the angle of bloodstains on tiles.

[0029] Reference numerals: 1. Measuring ruler; 2. Drive groove; 201. Slide groove; 202. Sealing block; 203. First magnetic block; 204. First sealing ring; 205. Second magnetic block; 206. Support wheel; 207. Support block; 208. First indicator line; 209. Second indicator line; 3. Cylinder; 301. Sealing block; 302. Measuring rod; 303. Second sealing ring; 304. Scale line; 305. Pull rod; 306. Identification plate; 4. First connecting pipe; 401. Second connecting pipe; 402. Conveying pipe. Detailed Implementation

[0030] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0031] Examples, such as Figures 1 to 2 As shown, this utility model proposes a tool ruler for inferring the impact angle of a blood droplet, including a measuring ruler 1, which has a measuring area and a comparison area (reference). Figure 7-8 The measuring area includes scales distributed around the measuring ruler 1, with a maximum length of 28cm and a minimum unit of 1mm. The comparison area includes multiple comparison holes of different sizes and shapes evenly distributed on the measuring ruler 1. These comparison holes are arranged in a 6x6 pattern. The measuring ruler 1 has angle and velocity readings marked on one side of the edge comparison holes. By measuring the width and length of the bloodstain, and finding the corresponding readings on the horizontally and vertically arranged scales, the intersection of the two readings indicates the shape of the bloodstain. By identifying the corresponding angle and velocity readings, the splash angle and splash velocity of the blood droplet can be determined.

[0032] During on-site investigation, the bloodstain can be directly compared with the comparison hole on measuring ruler 1. If the shape and size are consistent, the impact angle of the blood droplet can be directly read. In addition, the velocity of the blood droplet when it hits the target surface, or the drop height of the blood droplet under the action of gravity alone, can also be determined. If the bloodstain and the comparison hole do not match perfectly, a similarly matching comparison hole can be found, and the impact angle and impact velocity of the blood droplet can also be roughly inferred.

[0033] It should be noted that, taking a typical blood droplet with a volume of 60 μL as an example, this device prepared 576 bloodstain samples for two common stain-bearing objects: glass and ceramic tiles. The samples were prepared under experimental conditions with an initial velocity of 0, heights of 20 cm, 40 cm, 60 cm, 80 cm, 100 cm, and 150 cm, and impact angles of 15°, 30°, 45°, 60°, 75°, and 90°. The length and width of the bloodstains were measured, and based on this, a tool ruler for rapid on-site comparison and measurement of bloodstain angles was designed.

[0034] Specifically:

[0035] Table 1. Length and width of bloodstains (glass) at a 15° angle.

[0036]

[0037] Table 2. Length and width of bloodstains at a 30° angle (glass)

[0038]

[0039] Table 3. Length and width of bloodstains at a 45° angle (glass)

[0040]

[0041] Table 4. Length and width of bloodstains at a 60° angle (glass)

[0042]

[0043] Table 5. Length and width of bloodstains at a 75° angle (glass)

[0044]

[0045] Table 6. Length and width of bloodstains at a 90° angle (glass)

[0046]

[0047] Table 7. Length and width of bloodstains at a 15° angle (on tiles)

[0048]

[0049] Table 8. Length and width of bloodstains at a 30° angle (on ceramic tiles)

[0050]

[0051] Table 9. Length and width of bloodstains at a 45° angle (on tiles)

[0052]

[0053]

[0054] Table 10. Length and width of bloodstains at a 60° angle (on tiles)

[0055]

[0056] Table 11. Length and width of bloodstains at a 75° angle (on tiles)

[0057]

[0058] Table 12 Length and width of bloodstains at a 90° angle (tiles)

[0059]

[0060] This embodiment also includes two measuring pens, located on one side of the measuring ruler 1. The two measuring pens measure the width and length of the bloodstain, respectively. Each measuring pen includes a cylinder 3, inside which a sealing block 301 and a measuring rod 302 are slidably mounted. A second sealing ring 303 is fixedly installed around the sealing block 301. The measuring rod 302 has graduation lines 304 engraved on it. The sealing block 301 and the measuring rod 302 are fixedly connected. A pull rod 305 is fixedly installed on the sealing block 301. The pull rod 305 observes one side of the cylinder 3 and extends to the outside of the cylinder 3. An identification plate 306 is provided on the surface of the cylinder 3. The identification plate 306 indicates whether the measuring pen is measuring the width or length of the bloodstain. The corresponding measuring pen measures the width and length of the bloodstain. During measurement, pulling or pushing the pull rod 305 moves the measuring rod 302. When the length of the measuring rod 302 matches the length or width of the bloodstain, the length or width reading can be read through the graduation lines.

[0061] This embodiment also includes a coordinate positioning mechanism installed on the measuring ruler 1. The coordinate positioning mechanism positions the corresponding comparison hole on the measuring ruler 1 based on the data measured by the measuring pen. After the measurement is completed by the measuring pen, the corresponding comparison hole on the measuring ruler 1 will be directly indicated, thus facilitating a quick and accurate determination of the splash angle and speed of blood. The coordinate positioning mechanism includes a drive groove 2 and a sliding groove 201 located on the four sides of the measuring ruler 1. The sliding groove 201 is located above the drive groove 2 and communicates with the surface of the measuring ruler 1. A magnetic sealing block is slidably installed in the drive groove 2, and a designated block that moves synchronously with the magnetic sealing block is slidably installed in the sliding groove 201. When the magnetic sealing block moves, it will drive the designated block to move under the action of magnetic force.

[0062] Specifically, the magnetic sealing block includes a first magnetic block 203 slidably installed in the drive groove 2, sealing blocks 202 fixedly installed on both sides of the first magnetic block 203, and a first sealing ring 204 fixedly installed around the sealing blocks 202. The drive groove 2 can be sealed by the first sealing ring 204. The magnetic sealing block includes a second magnetic block 205 slidably installed in the slide groove 201, support wheels 206 rotatably installed on both sides of the second magnetic block 205, and a support block 207 fixedly installed on the second magnetic block 205, extending above the surface of the measuring scale 1. Through the mutual magnetic attraction between the first magnetic block 203 and the second magnetic block 205, the second magnetic block 205 will move with the first magnetic block 203. When the second magnetic block 205 moves, it will drive the support block 207 to move.

[0063] A first indicator line 208 is fixedly installed between the support blocks 207 in the two horizontally arranged slides 201, and a second indicator line 209 is fixedly installed between the support blocks 207 in the two vertically arranged slides 201. The first indicator line 208 and the second indicator line 209 are perpendicular to each other. The intersection of the first indicator line 208 and the second indicator line 209 is the corresponding bloodstain parameter, which facilitates quick judgment of information when bloodstains splatter.

[0064] It is worth noting that first connecting pipes 4 are fixedly installed on both sides of the two horizontally arranged drive slots 2, and second connecting pipes 401 are fixedly installed on both sides of the two vertically arranged drive slots 2. Conveying pipes 402 are fixedly installed on both sides of the cylinder 3. Two conveying pipes on one cylinder 3 are fixedly connected to two first connecting pipes 4 respectively, and two conveying pipes 402 on the other cylinder 3 are fixedly connected to two second connecting pipes 401 respectively. The internal cross-sectional area of ​​the cylinder 3 is larger than the internal cross-sectional area of ​​the drive slot 2. The cylinder 3, the first connecting pipes 4, the second connecting pipes 401, the conveying pipes 402, and the drive slots 2 are all filled with transmission medium. When the measuring rod 302 is moved, the sealing block 301 will move. The moving sealing block 301 will cause the transmission medium inside the cylinder 3 to flow. The transmission medium is a liquid that can be compressed in an inoperable environment. The compressed transmission medium will enter the corresponding drive groove 2 through the delivery pipe 402 and the first connecting pipe 4 or the second connecting pipe 401. The hydraulic medium entering the drive groove 2 will compress the first magnetic block 203, thereby causing the first magnetic block 203 to drive the second magnetic block 205 to move. Thus, according to the measurement reading of the measuring pen, the position of the intersection of the first indicator line 208 and the second indicator line 209 can be changed, thereby achieving the purpose of quickly reading the reading.

[0065] The working principle of this embodiment is as follows: During on-site investigation, the bloodstain can be directly compared with the comparison hole on the measuring ruler 1. If the shape and size are consistent, the impact angle of the blood droplet can be directly read. In addition, the velocity of the blood droplet when it hits the target surface, or the drop height of the blood droplet under the action of gravity alone, can also be determined. If the bloodstain and the comparison hole do not match perfectly, a similarly consistent comparison hole can be found, and the impact angle and impact velocity of the blood droplet can be roughly inferred.

[0066] The identification plate 306 indicates whether the measuring pen is used to measure the width or length of the bloodstain. The corresponding measuring pen measures the width and length of the bloodstain. This requires moving the measuring rod 302, which in turn moves the sealing block 301. The moving sealing block 301 causes the transmission medium inside the cylinder 3 to flow. The transmission medium is a liquid that can be compressed under non-operating conditions. The compressed transmission medium enters the corresponding drive groove 2 through the delivery pipe 402 and the first connecting pipe 4 or the second connecting pipe 401. The hydraulic medium entering the drive groove 2 compresses the first magnetic block 203, causing the first magnetic block 203 to move the second magnetic block 205. Based on the measurement reading of the measuring pen, the position of the intersection of the first indicator line 208 and the second indicator line 209 can be changed, thus achieving rapid reading of the reading.

[0067] The above specific embodiments are merely several optional embodiments of this utility model. Based on the technical solution of this utility model and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A ruler for determining the impact angle of a blood droplet, characterized in that, Includes a measuring ruler (1), which has a measuring area and a comparison area. The measuring area includes a scale distributed around the measuring ruler (1). The maximum length of the scale is 28cm and the minimum unit of the scale is 1mm. The comparison area includes multiple comparison holes evenly distributed on the measuring ruler (1) and of different sizes and shapes. The multiple comparison holes are arranged in a 6*6 layout. The measuring ruler (1) is marked with angle and speed readings on one side of the edge comparison holes. Two measuring pens are placed on one side of the measuring ruler (1), and the two measuring pens measure the width and length of the bloodstain respectively; The coordinate positioning mechanism is installed on the measuring ruler (1) and positions the corresponding comparison hole on the measuring ruler (1) according to the data measured by the measuring pen.

2. A ruler for determining the impact angle of a blood droplet according to claim 1, characterized in that, The coordinate positioning mechanism includes a drive groove (2) and a slide groove (201) on the four sides of the measuring ruler (1). The slide groove (201) is located above the drive groove (2) and communicates with the surface of the measuring ruler (1). A magnetic sealing block is slidably installed in the drive groove (2), and a designated block that moves synchronously with the magnetic sealing block is slidably installed in the slide groove (201).

3. A ruler for determining the impact angle of a blood droplet according to claim 2, characterized in that, The magnetic sealing block includes a first magnetic block (203) that is slidably installed in the drive groove (2), and sealing blocks (202) are fixedly installed on both sides of the first magnetic block (203). A first sealing ring (204) is fixedly installed around the sealing block (202).

4. A ruler for determining the impact angle of a blood droplet according to claim 3, characterized in that, The designated block includes a second magnetic block (205) slidably installed in the slide groove (201), with support wheels (206) rotatably installed on both sides of the second magnetic block (205), and a support block (207) fixedly installed on the second magnetic block (205), the support block (207) extending above the surface of the measuring ruler (1).

5. A ruler for determining the impact angle of a blood droplet according to claim 4, characterized in that, A first indicator line (208) is fixedly installed between the support blocks (207) located in two horizontally arranged slides (201), and a second indicator line (209) is fixedly installed between the support blocks (207) located in two vertically arranged slides (201). The first indicator line (208) and the second indicator line (209) are perpendicular to each other.

6. A ruler for determining the impact angle of a blood droplet according to claim 5, characterized in that, The measuring pen includes a cylinder (3), in which a sealing block (301) and a measuring rod (302) are slidably installed. A second sealing ring (303) is fixedly installed around the sealing block (301). A scale line (304) is engraved on the measuring rod (302). The sealing block (301) and the measuring rod (302) are fixedly connected. A pull rod (305) is fixedly installed on the sealing block (301). The pull rod (305) observes one side of the cylinder (3) and extends to the outside of the cylinder (3). An identification plate (306) is provided on the surface of the cylinder (3).

7. A ruler for determining the impact angle of a blood droplet according to claim 6, characterized in that, The two horizontally arranged drive slots (2) are each fixedly installed with a first connecting pipe (4) on both sides, and the two vertically arranged drive slots (2) are each fixedly installed with a second connecting pipe (401) on both sides. The cylinder (3) is fixedly installed with a conveying pipe (402) on both sides. The two conveying pipes on one cylinder (3) are respectively fixedly connected to the two first connecting pipes (4), and the two conveying pipes (402) on the other cylinder (3) are respectively fixedly connected to the two second connecting pipes (401).

8. A ruler for determining the impact angle of a blood droplet according to claim 7, characterized in that, The cylinder (3), the first connecting pipe (4), the second connecting pipe (401), the conveying pipe (402), and the drive groove (2) are all filled with a transmission medium.

Images