A tape measure

Abstract

The present disclosure provides a tape measure. The tape measure comprises a housing, a main tape and a first hook, the housing is provided with an opening; the main tape comprises a plurality of tape strips and a fixing member, the fixing member is fixed to the movable end of all the tape strips; the tape strips are provided with a plurality of magnetic members, when the tape strips are extended out of the opening, any two adjacent tape strips extended out of the housing can be adsorbed together through the corresponding magnetic members, so that the parts of all the tape strips extended out of the housing are surrounded into a closed shape; at least one tape strip is provided with a first scale; the first hook is connected to the fixing member and is clamped outside the opening of the housing, for simultaneously pulling all the tape strips to extend out of the housing and be clamped on the surface of the object to be measured. The main tape composed of a plurality of tape strips has a certain bending strength, is suitable for length measurement of larger size, improves the measurement range, and can also reduce the precision loss caused by its own deformation.

Description

Technical Field

[0001] This disclosure relates to the field of measuring tools, and more specifically, to a measuring tape. Background Technology

[0002] Length measurement is required in various fields such as machining and engineering. Existing tools for measuring length mainly include vernier calipers, tape measures, laser trackers, and 3D optical measurement.

[0003] Vernier calipers can achieve high-precision measurements, but because they are mostly made of metal, they are heavy and only suitable for measuring small lengths. If the length exceeds 1 meter, the weight makes operation inconvenient. For lengths exceeding 1 meter, measuring tapes are often used, but existing measuring tapes have low strength and will deform under their own weight when extended, thus affecting measurement accuracy. Large coordinate measuring instruments such as laser trackers and 3D optical measuring instruments are expensive and require a constant temperature environment to maintain their accuracy, limiting their application range.

[0004] It should be noted that the information in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this disclosure is to provide a measuring tape that solves one or more problems existing in current measuring tapes.

[0006] According to one aspect of this disclosure, a measuring tape is provided, comprising:

[0007] A housing, wherein multiple rollers are disposed inside the housing, and an opening is provided on the housing;

[0008] The main ruler includes multiple ruler strips and fixing members. The fixing members are fixed to the movable ends of all the ruler strips. The main ruler is located inside the housing and can extend out from the opening. Multiple magnetic elements are provided on the ruler strips. When the multiple ruler strips extend out of the opening, the portions of any two adjacent ruler strips extending out of the housing can be attracted together by the corresponding magnetic elements, so that the portions of all the ruler strips extending out of the housing form a closed shape. At least one of the ruler strips is provided with a first scale.

[0009] The first hook is connected to the fixing part of the main ruler and is locked outside the opening of the housing. The first hook is used to simultaneously pull all the ruler strips out of the housing and lock them onto the surface of the object to be measured.

[0010] In one exemplary embodiment of this disclosure, the number of ruler strips is at least three.

[0011] In one exemplary embodiment of this disclosure, the plurality of magnetic elements on the ruler strip includes two magnetic element groups, the two magnetic element groups being respectively close to two opposite long sides of the ruler strip, and all the magnetic elements in each magnetic element group being distributed at intervals along the length direction of the ruler strip; on two adjacent ruler strips, the positions of the magnetic elements in the two magnetic element groups that are close to each other correspond one-to-one.

[0012] In one exemplary embodiment of this disclosure, the cross-section of the ruler strip in the width direction is arc-shaped, such that the two opposite sides of the ruler strip are concave and convex, respectively, and the convex surface of the portion of any ruler strip extending outside the housing is attracted together with the convex surface of the adjacent ruler strip by the magnetic element.

[0013] In one exemplary embodiment of this disclosure, the cross-section of the ruler strip in the width direction is arc-shaped, such that the two opposite sides of the ruler strip are concave and convex, respectively, and the convex surface of any part of the ruler strip extending outside the housing is attracted together with the concave surface of the adjacent ruler strip by the magnetic element.

[0014] In one exemplary embodiment of this disclosure, the magnetic element is made of neodymium iron boron, and the ruler is made of steel.

[0015] In one exemplary embodiment of this disclosure, the shape of the housing opening is the same as the shape of the portion of the ruler extending out of the housing.

[0016] In one exemplary embodiment of this disclosure, a limiting device for limiting the extension length of the ruler strip is provided on the inner side of the housing opening.

[0017] In one exemplary embodiment of this disclosure, the first hook is rotatably disposed on the fixing member and can rotate about the extension direction of the main ruler.

[0018] In one exemplary embodiment of this disclosure, the first hook is detachably disposed on the fastener.

[0019] In an exemplary embodiment of this disclosure, the fixing member includes a base, a fixing sleeve, a spring, a connecting rod, a sliding block, and a bushing. The base is fixed to the movable ends of all the ruler strips. The fixing sleeve is sleeved outside the base and forms a first cavity with the base. A through hole is provided on the side of the fixing sleeve opposite to the base in the extension direction of the ruler strip. The bushing is sleeved outside the fixing sleeve. The sliding block is located in the first cavity and has a protrusion that extends out of the through hole and is fixed to the bushing. The sliding block is also provided with a guide groove. One end of the connecting rod is fixed to the base, and the other end is slidably disposed in the guide groove and can move along the guide groove. The spring is sleeved outside the connecting rod, with one end fixed to the base and the other end fixed to the sliding block. The first hook is sleeved on the bushing.

[0020] In one exemplary embodiment of this disclosure, the housing is further provided with a plurality of rollers, the number of which is equal to the number of ruler strips, and the plurality of ruler strips are wound one-to-one on the plurality of rollers.

[0021] In one exemplary embodiment of this disclosure, the measuring tape further includes a vernier scale located outside the housing; the vernier scale includes a secondary scale and a second hook disposed on the secondary scale, the secondary scale being disposed on the main scale and slidable relative to the main scale, and having a second graduation, the second hook being used to engage with the first hook shown to engage on the surface of the object to be measured.

[0022] In one exemplary embodiment of this disclosure, the secondary ruler is fixed to the housing, or the secondary ruler is slidably sleeved on the main ruler.

[0023] In one exemplary embodiment of this disclosure, both the first hook and the second hook include a snap-fit ​​surface, and the snap-fit ​​surfaces of the first hook and the second hook are arranged opposite to each other or back to back; or both the first hook and the second hook include a hole positioning structure, which can be snapped into a hole on the object to be measured.

[0024] In one exemplary embodiment of this disclosure, the measuring tape further includes a display screen and an automatic testing unit. The display screen is disposed on the housing, and the automatic testing unit includes:

[0025] A displacement sensor, disposed inside the housing, is used to measure the length of the main scale strip extending out of the housing;

[0026] The processor, located inside the housing, is connected to the displacement sensor and is used to calculate the length of the object to be measured based on the length data sensed by the displacement sensor and display it on the display screen.

[0027] In one exemplary embodiment of this disclosure, the automatic testing unit further includes a temperature sensor disposed on the housing for sensing the ambient temperature; wherein, the processor is further configured to correct the length of the object under test based on the temperature data sensed by the temperature sensor, and display the corrected result as the actual length of the object under test on the display screen.

[0028] In one exemplary embodiment of this disclosure, the automatic testing unit further includes an angle sensor disposed within the housing, used to sense the angle between the main scale and the length direction to be measured; wherein, the processor is further used to correct the length of the object to be measured based on the angle data sensed by the angle sensor, and display the corrected result as the actual length of the object to be measured on the display screen.

[0029] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0031] Figure 1 This is a three-dimensional structural diagram of the measuring tape according to the present disclosure;

[0032] Figure 2 This is a schematic diagram of the structure of a ruler strip in one exemplary embodiment;

[0033] Figure 3 This is a cross-sectional schematic diagram of a main ruler composed of three ruler strips according to an embodiment of the present disclosure;

[0034] Figure 4 This is a cross-sectional schematic diagram of another main ruler composed of three ruler strips according to an embodiment of this disclosure;

[0035] Figure 5 This is a cross-sectional schematic diagram of a main ruler composed of four ruler strips according to an embodiment of the present disclosure;

[0036] Figure 6 This is a cross-sectional schematic diagram of another main ruler composed of four ruler strips according to an embodiment of this disclosure;

[0037] Figure 7 This is a schematic diagram of a combined structure of a magnetic component and a ruler strip according to an embodiment of the present disclosure;

[0038] Figure 8 for Figure 1 A schematic diagram of the housing and main scale in the direction of main scale extension;

[0039] Figure 9 This is a schematic diagram of another opening structure of the shell in an embodiment of this disclosure;

[0040] Figure 10 for Figure 1 A schematic diagram of the housing and main scale in a direction perpendicular to the extension of the main scale;

[0041] Figure 11 This is a schematic diagram of a thickness compensation structure according to an embodiment of the present disclosure;

[0042] Figure 12 This is a schematic diagram of a measuring tape with a fixed vernier scale according to an embodiment of the present disclosure.

[0043] Figure 13 This is a schematic diagram of a measuring tape with a floating vernier scale according to an embodiment of the present disclosure;

[0044] Figure 14 This is a schematic diagram of a measuring tape structure with fixed and floating vernier scales according to an embodiment of the present disclosure;

[0045] Figures 15-17 This is a schematic diagram showing three possible combinations of the first and second hooks;

[0046] Figure 18 This is a schematic diagram of a measuring tape structure with a handle and a cover according to an embodiment of the present disclosure.

[0047] In the diagram: 10. Housing; 20. Main scale; 30. First hook; 101. Spool; 102. Opening; 210. Ruler strip; 220. Fixing element; 230. Magnetic element; 211. First graduation; 212. Through hole; 231. Metal mesh; 232. Neodymium iron boron; 221. Base; 222. Fixing sleeve; 223. Spring; 224. Connecting rod; 225. Sliding block; 226. Bushing; 227. First cavity; 228. Second cavity; 229. Guide groove; 40. Vernier scale; 41. Second scale; 42. Second hook; 411. Second graduation; 110. Display screen; 120. Handle; 130. Cover; 90. Object to be measured; Detailed Implementation

[0048] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.

[0049] This disclosure provides a measuring tape, such as... Figure 1 The diagram shows a three-dimensional structural representation of a measuring tape according to an embodiment of the present disclosure. It includes a housing 10, a main measuring tape 20, and a first hook 30. Multiple scrolls 101 are disposed within the housing 10, and an opening 102 is provided on the housing 10. The main measuring tape 20 includes multiple strips 210 and fixing members 220. The fixing members 220 are fixed to the movable ends of all the strips 210. The main measuring tape 20 is located within the housing 10 and can extend out from the opening 102. Multiple magnetic elements 230 are provided on the strips 210, and the multiple strips 210 extend out of the opening. At position 102, the portions of any two adjacent ruler strips 210 extending out of the housing 10 can be attracted together by the corresponding magnetic element 230, so that the portions of all ruler strips 210 extending out of the housing 10 form a closed shape; at least one ruler strip 210 is provided with a first scale 211; a first hook 30 is connected to the fixing element 220 of the main ruler 20 and is locked outside the opening 102 of the housing 10. The first hook 30 is used to simultaneously pull all the ruler strips 210 out of the housing 10 and lock them onto the surface of the object to be measured.

[0050] When using this measuring tape, pull the first hook 30 outward. The first hook 30, through the fixing member 220, causes all the ruler strips 210 to extend out of the opening 102 of the housing 10 at the same time. Two adjacent ruler strips 210 extending out of the opening 102 are attracted together by the magnetic member 230 set on the ruler strip 210. All the ruler strips 210 are attracted together and form a whole, forming a mutually supporting structure. The first hook 30 is locked on the surface of the object to be measured. The length of the object to be measured can be determined by reading the first scale 211 set on the main ruler 20.

[0051] The main scale 20 of this disclosure is composed of multiple scale strips 210, which enhances the strength of the portion of the main scale 20 extending out of the housing 10, giving it a certain bending strength in its free state and reducing accuracy loss due to deformation and bending caused by its own weight. Therefore, it can be used for measuring larger lengths, increasing the measurement range. On the other hand, due to the increased rigidity of the main scale 20, when measuring the external dimensions of the object to be measured, it can reduce the accuracy loss caused by deformation of the main scale 20 due to its own tensile stress; when measuring the internal dimensions of the object to be measured, it can reduce the accuracy loss caused by deformation of the inner side of the measured dimension. Therefore, the measurement accuracy of this measuring tape is also improved.

[0052] The measuring tape according to the present disclosure will now be described in detail:

[0053] In this application, the main ruler contains multiple ruler strips 210, meaning two or more. When only two ruler strips 210 are included, they can be magnetically attached back-to-back by the magnetic component 230, with the first graduation 211 facing outwards, which also enhances strength. Preferably, the main ruler contains three or more ruler strips 210, thereby forming a more three-dimensional structure and significantly improving the overall strength of the main ruler 20.

[0054] like Figure 2 The diagram shows a schematic of a ruler strip 210 in an exemplary embodiment. The first graduation 211 on the ruler strip 210 can be set to millimeter, centimeter, or other graduations as needed for measurement. It can be set on only one ruler strip 210 or on each ruler strip 210 to facilitate selection of the most convenient ruler strip 210 for reading. To facilitate reading, the first graduation 211 on the main ruler 20 may contain fluorescent material. In a main ruler composed of multiple ruler strips, the first graduation can be set on only one ruler strip or on all ruler strips to facilitate reading from different directions.

[0055] As shown in the figure, multiple magnetic elements 230 are provided on the ruler strip 210. All magnetic elements 230 are divided into two groups: a first magnetic element group and a second magnetic element group. The two magnetic element groups are located near opposite long sides of the ruler strip 210, respectively. That is, the upper row of magnetic elements in the figure represents the first magnetic element group, and the lower row represents the second magnetic element group. This way, when two ruler strips 210 are close together, the two magnetic element groups located on their adjacent long sides will more easily attract each other. Figure 3 Taking the main ruler composed of three ruler strips as an example, when the lower sides of the left and right ruler strips 210 are close together, the magnetic attraction groups above and below the two ruler strips are closest, and magnetic attraction occurs. Similarly, when any two ruler strips 210 are close together, the two magnetic attraction groups on each ruler strip 210 will attract the magnetic attraction groups on the adjacent ruler strips. Clearly, the side length and angle of the triangle are determined by the width of the ruler strips 210 and the included angle between adjacent ruler strips. For example, when the included angle between the three coiled ruler strips 210 is 120° and the widths of the three ruler strips 210 are equal, the cross-section of the main ruler composed of the three ruler strips 210 is approximately a closed equilateral triangle, as shown below. Figure 3 As shown. When two of the three ruler strips 210 have the same width but are different from the width of the third ruler strip, the cross-section of the main ruler 20 formed by the three ruler strips 210 is approximately a closed isosceles triangle, as shown. Figure 4 As shown. That is to say, the widths of multiple ruler strips 210 can be equal or unequal. In... Figure 5In the exemplary embodiment shown, the main ruler includes four ruler strips, all of equal width. The main ruler 20, formed by the magnetic attraction of the four strips, has a cross-section that is approximately a closed square. Those skilled in the art will understand that when the number of ruler strips 210 is greater, the cross-section of the main ruler formed by all the strips will be a corresponding polygon, which will not be listed here.

[0056] Understandably, the closer the two ruler strips (210), the easier it is for them to attract each other magnetically. (Continue to refer to...) Figure 2 Each magnetic component 230 in each magnetic component group is distributed at intervals along the length of the ruler strip 210. On adjacent ruler strips 210, the positions of the magnetic components 230 in the two closest magnetic component groups should correspond one-to-one, so that adjacent ruler strips 210 can attract each other at the same length, thus allowing multiple ruler strips 210 to form a single unit. The distance between each magnetic component group and the edge of the long side of the ruler strip 210 can be set according to actual needs and is not specifically limited here.

[0057] The magnetic elements 230 within a magnetic element group on the ruler 210 can be evenly spaced. This even spacing helps prevent misalignment and deformation during magnetic attraction after extension. Alternatively, the magnetic elements 230 within a magnetic element group can be unevenly spaced to prevent magnetic attraction between layers of magnetic elements 230 after the ruler 210 is wound onto the roll 101. Furthermore, the distribution patterns of two magnetic element groups on the same ruler 210 can be the same or different. That is, the distribution patterns of the magnetic elements 230 in the first magnetic element group and the second magnetic element group can be the same or different, as long as the distribution of the magnetic elements 230 in any magnetic element group and the other magnetic element group with which it is coupled is consistent, a one-to-one magnetic correspondence can be achieved. Preferably, the spacing between the magnetic elements 230 in each group is 5 to 10 times the width of the ruler 210.

[0058] Continue to refer to Figures 3-5 As a further improvement, the cross-section of the ruler strip 210 in the width direction is set to an arc shape, making the two opposite sides of the ruler strip 210 concave and convex respectively. This allows for two different ways of magnetically attracting adjacent ruler strips 210. For example... Figures 3-5 As shown, this is one type of magnetic attraction method. In this method, the convex surface of the portion of one ruler strip 210 extending outside the housing 10 is attracted to the convex surface of an adjacent ruler strip 210 via a magnetic component 230. That is, when two adjacent ruler strips 210 are magnetically attracted together, the convex surfaces of the two ruler strips 210 are pressed together. Overall, all the arc-shaped openings 102 of the ruler strips 210 face outwards, thus forming the shape shown in the figure. Figure 6As shown, another magnetic attraction method is used, taking a main ruler composed of four strips as an example. The convex surface of the part of one strip 210 extending outside the housing 10 is attracted to the concave surface of the adjacent strip 210 by a magnetic component 230. That is, when two adjacent strips 210 are magnetically attracted together, the convex surface of one strip 210 fits against the concave surface of the other strip 210, and the arc-shaped openings 102 of all strips 210 face inward, thus forming a quadrilateral shape as shown in the figure. The cross-section of the strips 210 is set to be arc-shaped to facilitate the joining of two adjacent strips 210 together.

[0059] In this application, the stronger the magnetism of the magnetic component 230, the easier it is for adjacent ruler strips 210 to be magnetically attracted, and the better the stability after attraction, which helps to maintain strong rigidity. The material of the magnetic component 230 is preferably neodymium iron boron (NdFeB), which has extremely high magnetic energy product and coercivity, as well as high energy density, enabling it to achieve ideal magnetic attraction. The material of the ruler strips 210 needs to be selected to have certain bending properties, elasticity, and rigidity, and should also be a non-magnetic material. Specifically, plastic sheets, alloy materials, etc., can be used, with stainless steel strips being preferred, as stainless steel ruler strips 210 are lightweight, easy to carry and use. A self-lubricating wear-resistant coating can be applied to the surface of the ruler strips 210 to reduce damage to the first scale 211 due to friction when adjacent ruler strips 210 are magnetically attracted together.

[0060] The magnetic component 230 and the ruler strip 210 can be fixed in various conventional ways. For example, such as... Figure 7 The diagram shows a combined structure of a magnetic component 230 and a ruler strip 210. Through holes can be formed in the ruler strip 210. The magnetic component 230 is composed of a metal mesh 231 and flexible neodymium iron boron (NdFeB) 232, and can be mass-produced through pre-forming. The magnetic component 230 has the same shape and thickness as the through holes in the ruler strip 210. The magnetic component 230 is embedded in the through holes, and the metal ring around the metal mesh 231 is welded to the edge of the through holes in the ruler strip 210. The metal mesh 231 serves to fix and support, ensuring a reliable connection between the flexible NdFeB 232 and the ruler strip 210. Alternatively, the magnetic component 230 can be fixed in the through holes by other mechanical means, or it can even be made into a thin sheet and wrapped inside the ruler strip 210. This application does not specifically limit the fixing method of the two components.

[0061] Figure 8 for Figure 1The diagram shows the housing 10 and the main ruler 20 in the direction of the main ruler's extension (the fastener and the first hook are not shown). In this exemplary embodiment, the housing 10 contains three rollers 101, and the main ruler includes three ruler strips 210, which are wound around the three rollers 101 respectively. As can be seen from the top view, the protruding ends of the three coiled ruler strips 210 wound around the rollers 101 are close to each other, and adjacent ruler strips 210 form a certain angle with each other. The three coiled ruler strips 210 are arranged radially. Because the protruding ends of the three ruler strips 210 are close to each other, they can smoothly form a whole through magnetic attraction after extending out of the housing 10. When the ruler strips 210 retract into the housing 10, due to the different orientations of the rollers 101, the three ruler strips 210 are pulled apart and independently wound around the rollers 101.

[0062] The housing 10 of the measuring tape can be configured to match the shape of the multiple coiled measuring strips 210. (Continue to refer to...) Figure 1 and Figure 8 The housing 10 has a radial shape that matches the three coiled ruler strips 210, thus creating a certain spatial constraint on the coiled ruler strips 210 and preventing them from scattering. An opening 102 is provided on the housing 10 for the ruler strips 210 to extend out; therefore, the opening 102 should correspond to the movable end of the ruler strip 210. In this embodiment, the shape of the opening 102 is the same as the triangle formed by the three ruler strips 210 extending out of the housing 10, i.e., it is triangular. This restricts the position and angle of the ruler strips 210 when they extend, facilitating the approach and magnetic attraction of adjacent ruler strips 210. When the ruler strips 210 are pulled outward, the magnetic attraction process of adjacent ruler strips 210 may occur after they extend out of the housing 10 or it may begin inside the housing 10, depending on factors such as the space of the housing 10, the spacing of the ruler strips 210, and the magnetic force of the magnetic component 230.

[0063] In other implementations, such as Figure 9 The diagram shows another opening structure. The opening can also be configured as three independent strip openings 102, arranged in a triangular shape formed by the ruler strips 210 extending out of the housing 10. Each ruler strip 210 extends from its corresponding strip opening 102. The independent openings 102 help separate the retracted ruler strips 210, but the magnetic attraction process when the ruler strips 210 extend outwards occurs after they extend out of the housing 10. When the ruler strips 210 adopt an arc-shaped structure, the shape of the strip openings 102 can also be an arc shape that matches the shape of the ruler strips 210, thus facilitating the entry and exit of the ruler strips 210.

[0064] It is understood that when the number of ruler strips 210 is other than the above-described embodiment, the housing 10 can be set to a corresponding shape, or an opening 102 of a corresponding shape can be provided on the housing 10 to facilitate the storage and extension of the ruler strips 210. These will not be listed individually here.

[0065] In this application, a wound elastic element can be provided inside the housing 10 to realize the retraction of the ruler strip 210. One end of the elastic element is fixed to the drum 101, and the other end is fixed to a fixed shaft. When the ruler strip 210 is stretched, the drum 101 rotates, causing the elastic element to compress and rotate. When the external force is removed, the elastic element retracts, causing the drum 101 to rotate in the opposite direction, and the ruler strip 210 automatically retracts. Of course, the automatic retraction of the main ruler 20 can also be achieved by a structure, and this application does not impose any special limitations on this.

[0066] As a further improvement, a limiting device can be provided inside the opening 102 of the housing 10 to limit the extension length of the ruler strip 210. This device can fix the ruler strip 210 after it extends to facilitate reading. The limiting device can be a clamping slider, which presses the ruler strip 210 to one side along its thickness direction to lock it in place. This prevents the ruler strip 210 from winding in or out, avoiding unintentional winding or unwinding of the clamping slider relative to the housing 10 during measurement. On the other hand, when the object being measured is high or low, it is difficult for the measuring operator's line of sight to be level with the other edge of the object and the main ruler 20, which can easily lead to reading errors due to line-of-sight deviation. Locking the main ruler 20 with the limiting device allows the measuring tape to be removed from the object before reading, facilitating measurement. Multiple limiting devices can be provided, each located at a corresponding position of the ruler strip 210, or only one device can be provided to limit all ruler strips 210 simultaneously. Since the winding elastic element and the limiting device can be implemented using existing structures, they are not shown in the figure.

[0067] In this application, the fastener 220 in the main ruler 20 is used to secure the movable ends of all ruler strips 210 together, so that all ruler strips 210 extend or retract synchronously. (Reference) Figure 1 and Figure 10 , Figure 10 for Figure 1 The schematic diagram of the housing and main scale in the direction perpendicular to the extension of the main scale shows that the fastener 220 may include a cylindrical structure that is sleeved on the outside of the movable end of the multiple scale strips 210 and fixed by means of riveting, welding bolts or other methods.

[0068] In this application, the shape of the first hook 30 can be selected according to the characteristics of the object to be measured. For example, when it needs to be fixed to the inner or outer surface of the object to be measured, the first hook 30 has a snap-fit ​​surface, which can face the housing 10 or face away from the housing 10. When it needs to be fixed in a hole in the object to be measured, the first hook 30 can include a hole positioning structure, such as a column protruding along the width direction of the ruler strip 210. This hole positioning structure can extend into the hole in the object to be measured to realize the length measurement of the perforated structure.

[0069] In one exemplary embodiment, the first hook 30 is rotatably disposed on the fixing member 220, allowing it to be positioned about the extension direction of the main scale 20 (i.e., Figure 10 The device can be rotated horizontally to find the most suitable position to lock onto the surface of the object to be measured. Furthermore, the first hook 30 is detachably mounted on the fixing member 220 for easy replacement.

[0070] When using a measuring tape, different measurement methods can be selected depending on the object being measured, such as hanging it on the object or placing it on top of the object. The difference between the two methods lies in the thickness of the first hook 30 at the head of the measuring tape. To avoid the thickness of the first hook 30 affecting measurement accuracy, a thickness compensation structure can be installed on the fixing part 220 of the main scale 20.

[0071] refer to Figure 11 This is a schematic diagram of a thickness compensation structure. The fixing components include a base 221, a fixing sleeve 222, a spring 223, a connecting rod 224, a sliding block 225, and a bushing 226. The base 221 is fixed to the movable ends of all ruler strips 210, used to fix the ruler strips 210 together. The fixing sleeve 222 is sleeved on the base 221, forming a first cavity 227 between the fixing sleeve 222 and the base 221. A through hole is provided on the side of the fixing sleeve 222 opposite to the base 221 in the ruler strip extension direction. The bushing 226 is sleeved on the fixing sleeve 222. The sliding block 225 is located in the first cavity 227 between the fixing sleeve 222 and the base 221, and the sliding block 225 has a protrusion that extends out of the through hole on the fixing sleeve 222 and is fixed to the bushing 226, thereby connecting the fixing sleeve 222 and the bushing 226 together. The sliding block 225 is also provided with a heart-shaped guide groove 229 as shown in the figure. One end of the connecting rod 224 is fixed to the base 221, and the other end is slidably disposed in the guide groove 229 and can move along the guide groove 229. The spring 223 is sleeved on the outside of the connecting rod 224, with one end fixed to the base 221 and the other end fixed to the sliding block 225. The first hook 30 is sleeved on the bushing 226 and can rotate around the bushing 226.

[0072] When the first hook 30 needs to be placed on the object to be measured, the first hook 30 is moved to the left relative to the fixing member 220. The first hook 30 drives the bushing 226 and the sliding block 225 to move to the left until the movable end of the connecting rod 224 slides to the rightmost limit position in the guide groove 229. At this time, the spring 223 is in a compressed state, and the second cavity 228 between the bushing 226 and the fixing sleeve 222 disappears, and the two fit together. The reading at this time is the actual length of the object to be measured. When the first hook 30 needs to be attached to the object to be measured, it is pulled to the right relative to the fixing member 220. The first hook 30 drives the bushing 226 and the sliding block 225 to move to the right until the movable end of the connecting rod 224 slides to the leftmost extreme position in the guide groove 229. At this time, the spring 223 is in a stretched state, and a second cavity 228 is formed between the bushing 226 and the fixing sleeve 222. The width of the second cavity 228 in the length direction of the ruler strip 210 is equal to the thickness of the ruler strip 210. The reading at this time is the actual length of the object to be measured. It can be seen that the horizontal movement range of the first hook 30 at the left and right extreme positions is equal to the width of the cavity in the length direction of the ruler strip 210, which is the thickness d of the ruler strip 210. This can compensate for the error caused by different measurement methods and the thickness of the first hook 30. Figure 11 The structure shown is only one example; in other implementations, other structures may be used to achieve thickness compensation.

[0073] To achieve more accurate measurements, reference Figures 12-14 The measuring tape of this embodiment may further include a vernier scale 40, which is located outside the housing 10 and includes a secondary scale 41 and a second hook 42 disposed on the secondary scale 41. The secondary scale 41 is disposed on the main scale 20 and can slide relative to the main scale 20, and is provided with a second scale. The second hook 42 is used to cooperate with the first hook 30 to lock onto the surface of the object to be measured.

[0074] In one exemplary embodiment, the vernier scale 40 is a fixed vernier scale, such as... Figure 12 The diagram shows a measuring tape with a fixed vernier caliper. The vernier scale 41 of the vernier scale 40 is fixed to the housing 10 and located at the opening of the housing 10. The second latch 42 is also always in a fixed position. After the main scale 20 extends, the accurate size of the object to be measured can be obtained through the first graduation 211 on the main scale 20 and the second graduation 411 on the vernier scale 41. This fixed vernier scale 40 allows for precise reading of a length data point in a single measurement.

[0075] In one exemplary embodiment, reference is made to Figure 13The vernier scale 40 is a floating vernier scale, meaning that the vernier scale 41 is slidably mounted on the main scale 20, and the second hook 42 can slide along with the vernier scale 41 on the main scale 20. Because the floating vernier can move, length data from multiple different positions can be read in a single measurement, improving measurement efficiency. Multiple floating vernier scales 40 can be installed on a single measuring tape. The surface of the floating vernier scale 40 in contact with the main scale 20 can be coated with a self-lubricating, wear-resistant coating to reduce friction when the floating vernier scale 40 and the main scale 20 slide against each other, minimizing damage to the first graduation 211.

[0076] In yet another exemplary embodiment, reference is made to... Figure 14 The measuring tape can be equipped with one fixed vernier scale 40 and one or more floating vernier scales 40. When the main scale 20 retracts into the housing 10, the first hook 30 will lock onto the outside of the vernier scale 40 because the vernier scale 40 will occupy a certain space.

[0077] Whether it is a fixed vernier scale or a floating vernier scale, its second hook 42 should cooperate with the first hook 30, that is, the engaging surface of the second hook 42 and the engaging surface of the first hook 30 can be set opposite to each other to hang on the outer surface of the object to be measured 90. Figure 15 As shown, the engaging surfaces of the second hook 42 and the first hook 30 are positioned opposite each other inside the object 90 to be measured, as... Figure 16 As shown; or both the first hook 30 and the second hook 42 include hole positioning structures, which can be locked into holes on the object to be measured 90 to achieve measurement of the distance between the two holes, such as Figure 17 As shown. Therefore, the second hook 42 can also be configured as a detachable structure for easy replacement.

[0078] The second graduation 411 on the vernier scale can be divided into 10-degree, 20-degree, and 50-degree graduations, etc. The vernier scale 40 and the main scale 20 work together to perform more precise measurements. For example, the first graduation 211 on the main scale 20 is in millimeters (mm), and the second graduation 411 on the vernier scale 40 uses a 50-degree graduation of 49mm. Each graduation on the vernier scale 40 that is close to 1mm actually has a length of 0.98mm. An indicator line is engraved every 5 graduations on the vernier scale 40, and the corresponding reading on the vernier scale 40 is 0.1mm. A rectangular window can be set on the side of the vernier scale 40 corresponding to the graduation on the main scale 20. The window is covered with a transparent sheet with the second graduation 411, so that the measuring personnel can directly see through the transparent sheet the relative position of the "0" graduation of the second graduation 411 on the vernier scale to the main scale 20, and see which graduation on the vernier scale 40 and the main scale 20 are aligned. The vernier scale 40 can be made of aluminum alloy to achieve lightweight design. To facilitate comparison between the scales on the vernier scale 40 and the main scale 20, the first scale 211 on the main scale 20 contains fluorescent material. When the corresponding light-leaking groove on the vernier scale 40 illuminates the first scale 211 on the main scale 20, aligning the second scale 411 on the vernier scale 40 with the corresponding scale 211 on the main scale 20, it can be displayed differently from other scales for easy indication. Alternatively, the lines on the main scale 20 can be blue, and the vernier scale 40 can use transparent material and yellow semi-transparent lines, so that the scales appear green when they align. Of course, other methods can also be used for special indication, such as integrating a photoelectric sensor on the fixed vernier scale 40 for signal acquisition, processing, and display.

[0079] In this disclosure, to improve the convenience of measurement and reading, in one exemplary embodiment, the measuring tape also includes a display screen 110 and an automatic testing unit. The display screen 110 is disposed on the housing 10, and the automatic testing unit is used to automatically read length data and display the data on the display screen 110, allowing the measuring person to directly read the data. The automatic testing unit includes a displacement sensor and a processor. The displacement sensor is disposed inside the housing 10 and is used to measure the length of the strip 210 of the main scale 20 extending out of the housing 10. The processor is also disposed inside the housing 10 and connected to the displacement sensor, used to calculate the length of the object to be measured based on the length data sensed by the displacement sensor and display it on the display screen 110. The displacement sensor can be of various types, such as strain gauge, inductive, differential transformer (LVDT), eddy current, and Hall effect sensors. In one specific implementation, the displacement sensor can calculate the extended length based on the number of extended magnetic elements 230.

[0080] For steel measuring tapes (210), due to the thermal expansion and contraction properties of steel, the measurement accuracy is easily affected by temperature during precision measurement. According to the metrological verification procedure of JJG 4-1999 "Steel Measuring Tapes," steel measuring tapes are classified into two accuracy grades: I and II. The permissible errors Δ between any two lines are: ΔⅠ=±(0.1+0.1L)mm; ΔⅡ=±(0.3+0.2L)mm; where L is the test length in meters. That is, when measuring a 3-meter length, the permissible error for grade I is ±0.4mm, and for grade II it is ±1mm. The permissible error range is within 0.8mm and 2mm. Even using a qualified measuring tape, its accuracy often fails to meet the relative positional accuracy required for assembly.

[0081] Based on this, in one exemplary embodiment, the automatic testing unit further includes a temperature sensor disposed on the housing 10 for sensing the ambient temperature of the measuring tape. The processor can also correct the length data of the object to be measured calculated by the displacement sensor based on the temperature data sensed by the temperature sensor, and display the corrected result as the actual length of the object to be measured on the display screen 110. In one embodiment, the processor corrects the length of the object to be measured according to the following equation:

[0082] L t =L + ΔL + α·L(t - t0)

[0083] Among them, L t ΔL is the actual length of the object under test at temperature t; L is the uncorrected measurement value of the displacement sensor at standard temperature t0; ΔL is the deviation between the actual length of the object under test and the test length of the displacement sensor at standard temperature t0; α is the coefficient of thermal expansion of the ruler strip 210.

[0084] Where α·L(t-t0) represents the deviation due to thermal expansion at temperature t. For a measuring tape that has undergone self-calibration, α·L(t-t0) can be calculated by measuring the working temperature t and the approximate extension length L of the measuring tape. When L is calculated based on the number of magnetic components 230, ΔL becomes a function of the number of magnetic components 230, and α·L(t-t0) becomes a function of the number of magnetic components 230 and t0. The data L after correction using the above method is... t This results in a high-precision and highly reliable length measurement.

[0085] As an optimization, the automatic testing unit may also include an angle sensor, housed within the housing 10, for sensing the angle between the main scale 20 and the direction of the length to be measured. The processor further corrects the length of the object to be measured calculated by the displacement sensor based on the angle data sensed by the angle sensor, displaying the corrected result as the actual length of the object on the display screen 110. This avoids the problem of measurement data accuracy being affected by the angle at which the main scale 20 extends. The angle sensor can be a miniature gyroscope.

[0086] Furthermore, additional functions can be provided on the housing 10 to facilitate use by measurement personnel, such as setting a dedicated button to zero the offset for quick self-calibration. A dedicated button can also be provided to number and store measured dimensions and deviations, or to recall and redisplay them.

[0087] Further, refer to Figure 18 A handle 120 can also be provided on the housing 10 for easy carrying and operation. The handle 120 can also be used to house components such as batteries.

[0088] Further, refer to Figure 18 The housing 10 also features a foldable cover 130, with one side of the cover 130 fixed to the housing 10. When the main scale 20 retracts into the housing 10, the cover 130 extends along this side and covers the opening 102 in the housing 10, creating a cavity between the cover 130 and the housing 10. The first latch 30 is located within this cavity. The cover 130 provides protection for the first latch 30. When the main scale 20 needs to extend out of the housing 10 for measurement, the foldable cover 130 can simply be opened. The housing 10 may also be further equipped with auxiliary structures such as handles.

[0089] When using the measuring tape of this disclosure, some auxiliary tools can be used to improve measurement comfort and efficiency. For example, a length calibration ruler, which can have a triangular edge structure, can be used for self-calibration of the measuring tape. The length calibration ruler can be made of aluminum profile to achieve a lightweight design, and weight-reducing holes can be arranged while ensuring strength. Another example is a positioning tool, used by one person to fix or support the first hook or the middle part of the main scale, reducing deformation of the main scale due to its own weight and improving measurement accuracy. This positioning tool can be a suction cup, magnet, or double-sided easy-pull tape device to attach the measuring tape to the object to be measured.

[0090] Although relative terms such as "up" and "down" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples shown in the accompanying drawings. It is understood that if the device of the icon is flipped upside down, the component described as "up" will become the component described as "down." When a structure is "up" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0091] The terms “a,” “one,” “the,” “the,” and “at least one” are used to indicate the presence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion meaning and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.

[0092] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A measuring tape, characterized in that, include: A housing having an opening; The main ruler includes multiple ruler strips and fixing members. The fixing members are fixed to the movable ends of all the ruler strips. The main ruler is located inside the housing and can extend out from the opening. Multiple magnetic members are provided on the ruler strips. When the multiple ruler strips extend out of the opening, the portions of any two adjacent ruler strips extending out of the housing can be attracted together by the corresponding magnetic members, so that the portions of all the ruler strips extending out of the housing form a closed shape. At least one of the ruler strips is provided with a first graduation. The first hook is connected to the fixing part of the main ruler and is locked outside the opening of the housing. The first hook is used to simultaneously pull all the ruler strips out of the housing and lock them onto the surface of the object to be measured.

2. The measuring tape according to claim 1, characterized in that, The number of ruler strips is at least three.

3. The measuring tape according to claim 2, characterized in that, The multiple magnetic elements on the ruler strip include two groups of magnetic elements. The two groups of magnetic elements are respectively close to the two opposite long sides of the ruler strip. All the magnetic elements in each group of magnetic elements are distributed at intervals along the length of the ruler strip. On two adjacent ruler strips, the positions of the magnetic elements in the two groups of magnetic elements that are close to each other correspond one-to-one.

4. The measuring tape according to claim 3, characterized in that, The ruler strip has an arc-shaped cross-section in the width direction, so that the two opposite sides of the ruler strip are concave and convex, respectively. The convex surface of any part of the ruler strip that extends out of the housing is attracted together with the convex surface of the adjacent ruler strip by the magnetic component.

5. The measuring tape according to claim 3, characterized in that, The ruler strip has an arc-shaped cross-section in the width direction, so that the two opposite sides of the ruler strip are concave and convex, respectively. The convex side of any part of the ruler strip that extends out of the housing is attracted to the concave side of the adjacent ruler strip by the magnetic component.

6. The measuring tape according to claim 1, characterized in that, The magnetic component is made of neodymium iron boron, and the ruler is made of steel.

7. The measuring tape according to claim 1, characterized in that, The shape of the opening in the housing is the same as the shape of the portion of the ruler extending out of the housing.

8. The measuring tape according to claim 7, characterized in that, The inner side of the opening of the housing is provided with a limiting device for restricting the extension length of the ruler strip.

9. The measuring tape according to claim 1, characterized in that, The first hook is rotatably mounted on the fixing member and can rotate about the extension direction of the main scale.

10. The measuring tape according to claim 9, characterized in that, The first hook is detachably mounted on the fixing member.

11. The measuring tape according to claim 1, characterized in that, The fixing component includes a base, a fixing sleeve, a spring, a connecting rod, a sliding block, and a bushing. The base is fixed to the movable ends of all the ruler strips. The fixing sleeve is fitted over the base and forms a first cavity with the base. A through hole is provided on the side of the fixing sleeve opposite to the base in the extension direction of the ruler strip. The bushing is fitted over the fixing sleeve. The sliding block is located in the first cavity and has a protrusion that extends out of the through hole and is fixed to the bushing. The sliding block is also provided with a guide groove. One end of the connecting rod is fixed to the base, and the other end is slidably disposed in the guide groove and can move along the guide groove. The spring is fitted over the connecting rod, with one end fixed to the base and the other end fixed to the sliding block. The first hook is fitted onto the bushing.

12. The measuring tape according to claim 1, characterized in that, The housing also contains a plurality of rollers, the number of which is equal to the number of ruler strips, and the plurality of ruler strips are wound one-to-one on the plurality of rollers.

13. The measuring tape according to claim 1, characterized in that, The measuring tape also includes: A vernier scale is located outside the housing; the vernier scale includes a secondary scale and a second hook disposed on the secondary scale. The secondary scale is disposed on the main scale and can slide relative to the main scale, and is provided with a second scale. The second hook is used to cooperate with the first hook shown to lock onto the surface of the object to be measured.

14. The measuring tape according to claim 13, characterized in that, The auxiliary ruler is fixed to the housing, or the auxiliary ruler is slidably fitted onto the main ruler.

15. The measuring tape according to claim 14, characterized in that, Both the first hook and the second hook include a snap-fit ​​surface, and the snap-fit ​​surfaces of the first hook and the second hook are arranged opposite to each other or back to back; or both the first hook and the second hook include a hole positioning structure, which can be snapped into a hole on the object to be measured.

16. The measuring tape according to any one of claims 1-15, characterized in that, The measuring tape also includes a display screen and an automatic testing unit. The display screen is mounted on the housing, and the automatic testing unit includes: A displacement sensor, disposed inside the housing, is used to measure the length of the main scale strip extending out of the housing; The processor, located inside the housing, is connected to the displacement sensor and is used to calculate the length of the object to be measured based on the length data sensed by the displacement sensor and display it on the display screen.

17. The measuring tape according to claim 16, characterized in that, The automated testing unit also includes: A temperature sensor, which is disposed on the housing, is used to sense the ambient temperature; The processor is further configured to correct the length of the object under test based on the temperature data sensed by the temperature sensor, and display the corrected result as the actual length of the object under test on the display screen.

18. The measuring tape according to claim 16, characterized in that, The automated testing unit also includes: An angle sensor, disposed inside the housing, is used to sense the angle between the main scale and the length direction to be measured; The processor is further configured to correct the length of the object under test based on the angle data sensed by the angle sensor, and display the corrected result as the actual length of the object under test on the display screen.

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