Tape measure including spring module

Abstract

To provide a tape measure that facilitates assembly and spring replacement using a spring module.SOLUTION: A tape measure including a spring module comprises: a housing; a bobbin that rotates inside the housing; a blade wound around a winding surface of the bobbin, and pulled out to the outside or retracted into the inside through an entrance in the housing; and a spring module including a spring housing, a rotary shaft accommodated in the spring housing, and a spring that connects the spring housing and the rotary shaft. The force of the spring can be transmitted to the bobbin through the rotary shaft, and using the spring module facilitates assembly and replacement of the rotary shaft and the spring.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a tape measure, and more particularly to a tape measure that utilizes a spring module for easy assembly and spring replacement. [Background technology]

[0002] A conventional tape measure includes a housing, a bobbin, a blade wound on the outer surface of the bobbin, and a spring for returning the bobbin and the blade to their original position. The spring is built into the housing and can return the blade to its original position, and a hook attached to the end of the blade can stop the end of the blade at a desired position.

[0003] In a tape measure, since the blade is associated with a maximum measurable length and easy scale reading, it is difficult to reduce its length and width, and therefore a method of realizing miniaturization through a spring can be considered.

[0004] U.S. Patent No. 11226187 includes a proposal to remove the spring between the tape reel and the rotating shaft and place it on both sides. However, by moving the spring to both sides, the spring placed on the side may not be able to provide sufficient force. Also, if the width of the spring placed on the side is increased, the problem of the tape measure being unable to be made smaller may become prominent again. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a parallel spring tape measure that can reinforce the force of the springs while arranging the springs of the tape measure to the side.

[0006] The present invention provides a tape measure in which two or more springs can be connected in parallel to one rotating shaft to increase the spring force.

[0007] The present invention provides a compact tape measure that efficiently utilizes the space inside the housing.

[0008] The present invention provides a tape measure that connects two or more springs in parallel to one rotating shaft, and can prevent biased weight on the rotating shaft by forming a balance between the springs. [Means for solving the problem]

[0009] According to an exemplary embodiment of the present invention, the tape measure may include a housing, a bobbin that rotates within the housing, a blade that is wound around the winding surface of the bobbin and is pulled out to the outside or retracted inside through an inlet of the housing, and a spring module that includes a spring housing, a rotating shaft housed within the spring housing, and a spring connecting the spring housing and the rotating shaft, and the force of the spring may be transmitted to the bobbin through the rotating shaft.

[0010] The spring module allows the rotating shaft and the spring to be assembled and separated together, and the rotating shaft can be directly connected to the bobbin while being mounted in the housing, or connected through a gear train. Unlike the conventional technology, the rotating shaft and the bobbin are not connected at both ends of the spring, and the rotating shaft and the spring are modularized.

[0011] The spring housing may include a hollow cylinder portion inserted into the bobbin and a hollow disk portion integral with the cylinder portion and positioned on one side of the bobbin. The spring housing may be formed using a metal sheet material, and may have an overall T-shaped cross section due to the cylinder portion and the disk portion.

[0012] A rotating shaft is provided in the spring housing so as to axially pass through the center of the cylinder portion and the disk portion, and one end of the rotating shaft is exposed to the outside of the cylinder portion so as to be interlocked with a bobbin, and one end of the spring is fixed to the spring housing, and the spring housing is fixed to the tape measure housing so that it cannot rotate about the center of the rotating shaft, thereby providing the effect of the spring being fixed to the tape measure housing.

[0013] The housing may be provided using a first housing covering one side of the bobbin and a second housing covering the other side of the bobbin. The first housing may cover a surface on which the spring and the disk portion are disposed. The first housing may further include a housing cover covering the disk portion.

[0014] A gear train may be interposed between the second housing and the bobbin to adjust the rotation ratio between the bobbin and the rotating shaft, and the gear train links the rotating shaft and the bobbin, and the ratio of the rotation of the bobbin to the rotation of the rotating shaft may be greater than 1.

[0015] In one example, the gear train may include a first gear that directly meshes with the rotating shaft, a second gear that is mounted in the second housing and meshes with the first gear, and a third gear that meshes with the second gear to transmit rotation to the bobbin, and the reduction ratio may be determined through the first to third gears. The second gear may be fixed to the second housing, and in this case, a gear train other than a planetary gear may be formed.

[0016] The cylinder portion of the spring housing may be in direct contact with the bobbin, with a part of the first housing interposed therebetween. Specifically, the first housing may include a hollow cylinder hub that rotatably supports the inscribed surface of the bobbin, and the cylinder portion of the spring housing may be provided in a structure that is inserted into the cylinder hub.

[0017] In addition, the spring module may be directly connected to the first housing without a cylinder hub, and the cylinder portion may directly support the inscribed surface of the bobbin so as to be rotatable. The maximum outer diameter of the spring is approximately 60 to 95% of the maximum outer diameter of the bobbin, allowing the tape measure housing to be made compact, and the ratio of the bobbin's wound head to the outer diameter of the rotating shaft can be maintained at approximately 200 to 600%.

[0018] If the winding head is too small, it may cause damage to the blade. Therefore, it may be desirable to design the winding head of the bobbin so that it maintains approximately 200 to 600% of the axis of rotation.

[0019] When the spring is disposed on the side, an additional elastic body may be further included, which is interposed between the rotating shaft and the bobbin inside the bobbin, and has one end fixed to the housing and the other end fixed to the rotating shaft.

[0020] The rotating shaft is rotatably mounted in the housing, and at least one spring and at least one additional elastic body can be connected in parallel to one rotating shaft. Two types of springs can connect one rotating shaft to the housing, and are appropriately arranged in the side space and the bobbin inner space to minimize the spring space, which can contribute to the miniaturization of the tape measure.

[0021] In this case, the winding direction of the spring and the additional elastic body, i.e., the direction in which force is applied, may be the same, and the mutual forces can be compensated for by being wound and unwound in the same direction. The spring and the additional elastic body may be fixed to the housing, which means that an end of the spring is fixed to the housing, and the housing and the end of the spring may be directly or indirectly connected to each other.

[0022] To reduce the spring space, a spring with a larger elastic modulus can be used, and by using a stronger spring or combination of springs, the number of spring rotations can be reduced compared to the number of bobbin rotations (i.e., the length of the blade).To this end, a gear train can be included between the housing and the bobbin on the other side of the bobbin to link the rotating shaft and the bobbin, and the ratio of the bobbin rotations to the rotating shaft rotations can be made greater than 1 through the gear train.

[0023] The additional elastic body may be built into the spring module and assembled together with the spring and the rotating shaft, and the rotating shaft may include a flange that divides the space in the cylinder hub where the additional elastic body is disposed from the space inside the housing cover where the spring is disposed.

[0024] An additional elastic body is inserted inside the cylinder portion to connect the first housing and the rotating shaft, and a spring is disposed inside the disk portion and the housing cover to connect the first housing and the rotating shaft.

[0025] Structurally, the spring housing may have a slit connecting the cylinder portion and the disk portion, and one end of an additional elastic body or spring may be fastened to the slit.

[0026] When connecting the additional elastic body and the spring to the rotating shaft, the additional elastic body and the spring can be connected at 180 degrees apart from each other around the rotating shaft. The rotating shaft can be pulled in different directions to achieve balance, and when there are three springs, they can be equally spaced at 120 degrees apart or appropriately distributed according to the distribution of force. It is preferable that the thickness of the spring is greater than the thickness of the additional elastic body, and the average thickness (Ts) of the spring may be about 2 to 4 times the average thickness (Ti) of the additional elastic body.

[0027] It may be desirable for the width of the additional elastic body to be approximately 2 to 5 times the width of the spring. Effect of the Invention

[0028] The tape measure of the present invention has a spring disposed on the side of the bobbin, while securing a minimum space between the bobbin and the rotating shaft, and an additional elastic body is disposed in the space to increase the pulling force of the spring. In this case, the spring can be connected to the rotating shaft in parallel with the additional elastic body, or conversely, it can be connected directly or indirectly to the housing.

[0029] The rotating shaft can be connected to the bobbin directly, either one-to-one or through a gear train. By making the number of rotations of the rotating shaft smaller than the number of rotations of the bobbin, the space occupied by the spring can be kept smaller, and although the springs are connected in parallel, additional elastic bodies can be actively used.

[0030] In particular, the additional elastic body does not connect between the rotating shaft and the bobbin, but can connect the rotating shaft and the housing for parallel connection. In this way, the tape measure of the present invention can strengthen the force of the spring by connecting two or more springs in parallel to one rotating shaft.

[0031] The tape measure of the present invention can be formed in a compact size by efficiently utilizing the space inside the housing, and the springs can be arranged in opposite directions to each other on the rotation axis or at equal intervals to form a mutual balance between the forces between the springs. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a diagram illustrating a tape measure according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram for explaining a cross section taken along line AA of the measuring tape in FIG. [Diagram 3] FIG. 3 is a diagram for explaining an exploded structure of the tape measure of FIG. [Figure 4]FIG. 4 is a diagram for explaining a spring module of the tape measure of FIG. [Diagram 5] FIG. 5 is a diagram for explaining a spring module of the tape measure of FIG. [Figure 6] FIG. 6 is a diagram for explaining the spring housing of FIG. [Figure 7] FIG. 7 is a diagram illustrating a cross section of a tape measure according to an embodiment of the present invention. [Figure 8] FIG. 8 is a diagram for explaining the spring module of the tape measure of FIG. [Figure 9] FIG. 9 is a diagram for explaining the spring module of the tape measure of FIG. [Figure 10] FIG. 10 is a view for explaining the spring housing of FIG. [Figure 11] FIG. 11 is a diagram illustrating a rotating shaft and a spring connection in a tape measure according to an embodiment of the present invention. [Figure 12] FIG. 12 is a diagram illustrating a cross section of a tape measure according to an embodiment of the present invention. [Figure 13] FIG. 13 is a diagram for explaining the exploded structure of the tape measure of FIG. [Figure 14] FIG. 14 is a diagram for explaining the exploded structure of the tape measure of FIG. [Figure 15] FIG. 15 is a view for explaining the coupling of the first housing and the spring module in FIG. [Figure 16] FIG. 16 is a diagram for comparing spring modules of a tape measure according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings, but the present invention is not limited to or restricted by the embodiments. In this description, the same numbers refer to substantially the same elements, and under such rules, the contents described in other drawings can be quoted and described, and contents that are deemed obvious to those skilled in the art or that are repeated can be omitted.

[0034] FIG. 1 is a drawing for explaining a tape measure according to one embodiment of the present invention, FIG. 2 is a drawing for explaining the AA cross section of the tape measure of FIG. 1, FIG. 3 is a drawing for explaining the disassembled structure of the tape measure of FIG. 1, FIGS. 4 and 5 are drawings for explaining the spring module of the tape measure of FIG. 1, and FIG. 6 is a drawing for explaining the spring housing of FIG. 4.

[0035] 1 to 6, the tape measure 100 according to the present embodiment may include a housing 105, a rotating shaft 150, a bobbin 140, a blade 130, a spring 170, and a gear train 190. The blade 130 may be wound around a winding surface 142 of the bobbin 140 and pulled out through an entrance of the housing 105 for length measurement, or may be wound around the outer surface of the bobbin 140 while being pulled in for storage and stored. A spring may be used to pull the blade 130 into the housing 105 as in the past.

[0036] The housing 105 may be provided using a first housing 110 and a second housing 120. The first housing 110 may cover one side of the bobbin 140 and cover the side where the spring 170 is disposed, and the second housing 120 may cover the other side of the bobbin 140 and cover the side where the gear train 190 is disposed. The first housing 110 and the second housing 120 may be coupled to each other to form one housing 105.

[0037] The rotating shaft 150 is rotatably mounted at the center of the housing 105 and is connected to a spring 170 arranged on the side along the axial direction, and a distal end 154 of the rotating shaft 150, which is far from the spring 170, can be interlockingly connected to the bobbin 140 through a gear train 190.

[0038] The spring 170 may be provided on one side of the bobbin 140 where the first housing 110 is located, and may be interposed between the housing 105 and the bobbin 140. One end of the spring 170 may be fixed to the first housing 110, and the other end may be fastened to the rotating shaft 150.

[0039] In this embodiment, the spring 170 is located inside the spring housing 180 of the spring module 160 and is fastened to the spring housing 180, which may be fixed to the housing 105. Thus, the spring 170 may be indirectly fixed to the first housing 110 through the spring housing 180.

[0040] In addition, since the blade 130 is wound from the winding surface 142, if the diameter of the winding surface 142 is too small, it may cause damage to the blade 130. Therefore, in order to protect the blade 130, it is preferable that the outer diameter of the winding surface 142 is formed to be at least twice the outer diameter of the rotating shaft 150. By forming the outer diameter of the winding surface 142 to be 2 to 6 times the outer diameter of the rotating shaft 150, a space may be generated between the rotating shaft 150 and the bobbin 140.

[0041] The spring module 160 is configured by packaging the spring housing 180, the rotating shaft 150 mounted inside the housing cover 116, and the spring 170. The spring housing 180 may be formed of a metal plate, may be formed of a hollow cylinder portion 182 and a hollow disk portion 184, and may have an overall T-shaped cross section.

[0042] The rotating shaft 150 is disposed through the center of the spring housing 180 , and the spring 170 is accommodated in a hollow disk portion 184 , one end of which is fixed to the rotating shaft 150 and the other end of which is fixed to the inner wall of the hollow disk portion 184 .

[0043] In this embodiment, a slit 186 may be formed along the inner wall of the disk portion 184 of the screen housing 105, and an end of the spring 170 may be fixed using this slit 186.

[0044] With the spring housed in the screen housing 105, the housing cover 116 may cover the open side of the screen housing 105 to form a spring module 160. In this embodiment, the spring module 160 may be inserted from the outside of the first housing 110 and fixed.

[0045] For this purpose, the first housing 110 may be formed with a hollow cylinder hub 114 protruding inward from the center into which the body 112 and the spring module 160 can be inserted, and the inside of the cylinder hub 114 may be in close contact with the cylinder portion 182 of the spring module 160 to allow the rotating shaft 150 to enter the inside of the bobbin 140.

[0046] A through hole through which the distal end 154 of the rotating shaft 150 can protrude is formed at an end of the cylinder portion 182 of the spring housing 180, and the distal end 154 of the rotating shaft 150 can be exposed through the through hole. As the spring module 160 is coupled to the first housing 110, the distal end 154 of the rotating shaft 150 can also pass through the hollow cylinder hub 114 and enter the inside of the first housing 110 and the second housing 120.

[0047] The rotating shaft 150 may further include a flange 152 for dividing the cylinder portion 182 and the disk portion 184 of the spring housing 180. The flange 152 may divide the space of the spring housing 180 into two spaces 183 and 185.

[0048] A protrusion 188 may be formed on the outer surface of the spring housing 180, and the spring housing 180 may be coupled to the first housing 110 or the housing cover 116, thereby fixing the spring housing 180 so that it does not rotate with respect to the first housing 110. As the spring housing 180 is fixed to the first housing 110 in this manner, the spring 170 may be fixed to the housing 105.

[0049] The distal end 154 of the rotating shaft 150 passes through the cylinder hub 114 of the first housing 110 and may be connected to a gear train 190 provided between the second housing 120 and the bobbin 140. The distal end 154 of the rotating shaft 150 may be formed in a non-circular shape and may be connected to a first gear 192 located at the center of the gear train 190. In the gear train 190, the first gear 192 may be connected to a second gear 194 located at the periphery thereof, and the second gear 194 may be connected to a third gear 196 that interlocks with the bobbin 140.

[0050] In this embodiment, the third gear 196 is integrally formed on one side of the bobbin 140 and can be coupled to the second gear 194 while the bobbin 140 is mounted on the cylinder hub 114 and the second housing 120 is coupled to the first housing 110. In this embodiment, the second gear 194 is fixed to the second housing 120 and can only rotate without changing its position. The second housing 120 may include a gear cover 122 for protecting the first gear 192 and the second gear 194, and a hole may be formed in the center of the gear cover 122 through which the third gear 196 of the bobbin 140 and the distal end 154 of the rotating shaft 150 can enter.

[0051] The gear train 190 can be designed so that the rotation speed of the bobbin 140 is greater than the rotation speed of the rotating shaft 150. Even if the rotation speed of the rotating shaft 150 is reduced, a strong parallel spring combination is formed to prevent the force from becoming weak, and the spring space can be further reduced compared to the conventional art by using the strong parallel spring combination.

[0052] In this embodiment, the bobbin 140 and the rotating shaft 150 may be connected without a spring through the gear train 190. However, depending on the circumstances, the bobbin and the rotating shaft may be directly connected one-to-one regardless of the reduction in speed, and the structure for connecting the rotating shaft and the bobbin may be various methods such as a belt other than gears.

[0053] The first housing 110 rotatably supports the bobbin 140 using the cylinder hub 114, and the spring module 160 can be inserted and fixed from the outside of the first housing 110.

[0054] Since the spring module 160 includes the rotating shaft 150 and the spring 170 as a package, if the spring function is deteriorated or broken, the spring module 160 can be easily separated from the first housing 110 and repaired or replaced.

[0055] FIG. 7 is a diagram illustrating a cross section of a tape measure according to one embodiment of the present invention, FIGS. 8 and 9 are diagrams illustrating a spring module of the tape measure of FIG. 7, and FIG. 10 is a diagram illustrating a spring housing of FIG. 8.

[0056] 7 to 10, the tape measure according to this embodiment may include a housing 105, a rotating shaft 150, a bobbin 140, a blade 130, a spring 170, an additional elastic body 175, and a gear train 190.

[0057] Compared with the previous embodiment, the tape measure of this embodiment has a spring module 160 further including an additional elastic body 175, which can reinforce the restoring force of the spring 170. For the description of other similar configurations, please refer to the description of the previous embodiment.

[0058] The rotating shaft 150 is rotatably mounted at the center of the housing 105 , and is connected to a spring 170 and an additional elastic body 175 along the axial direction, and can be interlockingly coupled to the bobbin 140 through a gear train 190 .

[0059] In this embodiment, the additional elastic body 175 may be provided as a leaf spring having the same structure as the spring 170, and may also have the same winding direction so as to provide a restoring force together with the spring 170 in the same direction.

[0060] The additional elastic body 175 may be located inside the bobbin 140 and interposed between the bobbin 140 and the rotating shaft 150. One end of the additional elastic body 175 may be fixed to the first housing 110 through a spring housing 180′, and the other end may be fastened to the rotating shaft 150.

[0061] In this embodiment, the spring 170 and the additional elastic body 175 are located inside the spring housing 180' of the spring module 160 and are bound to the spring housing 180', which may be fixed to the housing 105. Thus, the spring 170 and the additional elastic body 175 may be indirectly fixed to the first housing 110 through the spring housing 180'.

[0062] In this embodiment, one spring 170 and one additional elastic body 175 are connected to one rotating shaft 150, but in some cases, multiple identical or similar springs or additional elastic bodies may be provided, and in this case, each spring and additional elastic body may be connected in parallel to the rotating shaft 150 and the housing 105, and the forces of the springs may be mutually reinforced through mutual parallel connection.

[0063] The additional elastic body 175 can reduce the width of the spring 170 by providing additional force, and can efficiently utilize the internal space of the bobbin 140 that would otherwise be empty. The additional elastic body 175 can efficiently utilize the side space for the spring 170 and the internal space of the bobbin 140, and can contribute to the overall miniaturization of the tape measure.

[0064] In addition, since the blade 130 is wound from the winding surface 142, if the diameter of the winding surface 142 is too small, it may damage the blade 130. Therefore, in order to protect the blade 130, it is preferable that the outer diameter of the winding surface 142 is formed to be at least twice the outer diameter of the rotating shaft 150. When the outer diameter of the winding surface 142 is formed to be 2 to 6 times the outer diameter of the rotating shaft 150, a space may be generated between the rotating shaft 150 and the bobbin 140, and by disposing an additional elastic body 175 in this space, the additional elastic body 175 can assist the force that the spring 170 must withstand.

[0065] In this embodiment, the spring 170 and the additional elastic body 175 can be wound in the same direction with respect to the rotating shaft 150. Also, the winding of the rotating shaft 150 is applied to the spring 170 and the additional elastic body 175 simultaneously, and when either one is completely unwound or cannot be wound any more, the entire rotating shaft 150 may not move.

[0066] The spring module 160 is configured by packaging a spring housing 180', a rotating shaft 150 mounted inside the housing cover 116, an additional elastic body 175, and a spring 170. The spring housing 180' may be formed of a metal plate, may be formed of a hollow cylinder portion 182 and a hollow disk portion 184, and may have an overall T-shaped cross section.

[0067] In the spring housing 180', the rotating shaft 150 is disposed penetrating the center, and the additional elastic body 175 is accommodated in a hollow cylinder portion 182, one end of which is fixed to the rotating shaft 150 and the other end of which is fixed to the inner wall of the hollow cylinder portion 182. Also, the spring 170 is accommodated in a hollow disk portion 184, one end of which is fixed to the rotating shaft 150 and the other end of which is fixed to the inner wall of the hollow disk portion 184. In this embodiment, a slit 186' may be formed along the inner wall of the screen housing 105 passing through the entire cylinder portion 182 and the disk portion 184, and the ends of the additional elastic body 175 and the spring 170 may be fixed using this slit 186'.

[0068] The first housing 110 rotatably supports the bobbin 140 using the cylinder hub 114, and the spring module 160 may be inserted and fixed from the outside of the first housing 110. Also, a spring housing 180' may be provided separately, and an additional elastic body 175 may be fixed to the first housing 110 through the spring housing 180'.

[0069] Since the spring module 160 includes the rotating shaft 150, the additional elastic body 175, and the spring 170 in a package, if the spring function is deteriorated or broken, the spring module 160 can be easily separated from the first housing 110 and repaired or replaced.

[0070] FIG. 11 is a diagram illustrating a rotating shaft and a spring connection in a tape measure according to an embodiment of the present invention.

[0071] 11, the additional elastic body 175 may be fixed to the rotating shaft 150 at the side where the distal end 154 is located, centering on the flange 152, and the spring 170 may be fixed to the side where the proximal end is located, centering on the flange 152.

[0072] The average thickness (Ts) of the spring 170 may be formed to be thicker than the average thickness (Ti) of the additional elastic body 175. The width (Wi) of the additional elastic body 175 may be formed to be 2 to 5 times the width (Ws) of the spring 170.

[0073] The spring 170 and the additional elastic body 175 may be connected to the same side based on the center of the rotating shaft 150 (a), or the spring 170 and the additional elastic body 175 may be connected to the rotating shaft 150 in opposite directions (b). When there are three springs or additional elastic bodies, they may be appropriately arranged so that the force from the springs is uniformly distributed at about 120 degrees or according to the distribution.

[0074] In this embodiment, the spring 170 can generate sufficient force with a maximum outer diameter (Ds) of about 60 to 95% of the maximum outer diameter (Db) of the bobbin 140, and therefore the width (Ws) and thickness (Ts) of the spring 170 can be appropriately adjusted. Through this process, it is not necessary to expand the outer diameter of the spring 170 to be equal to the outer diameter of the bobbin, and therefore, a condition can be provided in which the additional elastic body 175 does not need to expand the outer diameter of the spring 170 more than necessary.

[0075] In addition, by forming the outer diameter (Ds) of the spring 170 smaller than the outer diameter (Db) of the bobbin 140, the center of the housing can be made a little thicker than the periphery, making it easier for an operator to grip the housing with their hands.

[0076] In this embodiment, the ratio of the diameter (Dw) of the winding surface 142 of the bobbin 140 to the outer diameter (Dx) of the rotating shaft 150 can be maintained at about 200 to 600%. This allows a space to be formed between the winding surface 142 and the rotating shaft 150, and the effect of preventing damage to the blade and spring reinforcement through the additional elastic body 175 can be expected.

[0077] Figure 12 is a diagram illustrating a cross section of a tape measure according to one embodiment of the present invention, Figures 13 and 14 are diagrams illustrating the disassembled structure of the tape measure of Figure 12, Figure 15 is a diagram illustrating the connection of the first housing and spring module of Figure 13, and Figure 16 is a diagram illustrating the replacement of the spring module of the tape measure of Figure 12.

[0078] 12 to 16, the tape measure 200 according to this embodiment may include housings 210, 220, a rotating shaft 250, a bobbin 240, a blade 230, a spring 270, an additional elastic body 275, and a gear train 290. The blade 230 is wound on a winding surface 242 of the bobbin 240 and may be pulled out or withdrawn to the outside through an opening of the housing.

[0079] The housing is provided using a first housing 210 and a second housing 220, and a spring module 260 may be mounted on the first housing 210, and while the spring module 260 is mounted, the rotating shaft 250 is rotatably mounted at the center of the housing and is simultaneously connected to a spring 270 and an additional elastic body 275 along the axial direction. A distal end 254 of the rotating shaft 250 may be coupled to the bobbin 240 via a gear train 290 so as to be movable with the bobbin 240.

[0080] In this embodiment, the spring module 260 is directly coupled to the first housing 210 without a cylinder hub, and can rotatably support the bobbin 240 while supporting the inscribed surface of the bobbin 240. That is, the spring housing 280 serves as a housing for the spring module 260, and serves as a medium for fixing the additional elastic body 275 and the spring 270 to the first housing 210, and can itself serve as a center for the rotation of the bobbin 240.

[0081] As shown in FIG. 13, the cylinder portion 282 of the spring module 260 of this embodiment may have a relatively larger diameter than the cylinder portion 182 of the previous embodiment, which may serve to relatively further reinforce the additional elastic body 275 or, conversely, to reduce the additional elastic body space and the overall tape measure size.

[0082] The additional elastic body 275 can assist with a larger force, the width of the spring 270 can be further reduced, and the internal space of the bobbin 240 that may otherwise be empty space can be more efficiently utilized.

[0083] As shown in FIG. 9, when first assembled, the first housing 210 and the spring housing 280 can be provided in a state of being connected together as one unit, and the tape measure can be easily assembled by connecting the first housing 210 and the second housing 220 around the bobbin 240 on which the blade 230 is wound.

[0084] Also, when assembling the first housing 210 and the second housing 220, if the proximal end of the rotating shaft 250 exposed at the center of the housing cover 216 is tightened with a wrench, the spring can be tensioned. In some cases, if the spring becomes loose, the housings can be separated and the rotating shaft 250 can be rotated in the tightening direction to reinforce the loosened force.

[0085] The spring module 260 may be provided in a package including a spring housing 280, a rotating shaft 250, an additional elastic body 275, a spring 270, and a housing cover 216, and a detailed description thereof may refer to the description of the previous embodiment. In the spring housing 280, the rotating shaft 250 is disposed through the center, the additional elastic body 275 is accommodated in a hollow cylinder portion 282, the spring 270 is accommodated in a hollow disk portion 284, and the outer end can be bent and fixed through a slit 286.

[0086] For this, the first housing 210 is formed with a hole 212 into which the spring module 260 can enter without a cylinder hub, and like the spring module 260 , the additional elastic body 275 and the rotating shaft 250 can enter inside the bobbin 240 .

[0087] The distal end of the rotating shaft 250 protrudes from the end of the cylinder portion 282 of the spring housing 280 , and the distal end of the rotating shaft 250 passes through the bobbin 240 and can be coupled with the gear train 290 of the second housing 220 .

[0088] A protrusion 288 or a bent portion may be formed on the outer surface of the spring housing 280, and the spring housing 280 may be coupled to the first housing 210 or the housing cover 216. When the spring housing 280 is fixed to the first housing 210, the spring 270 and the additional elastic body 275 may be fixed to the housing.

[0089] The distal end 254 of the rotating shaft 250 is connected to a gear train 290 in the second housing 220, and the rotating shaft 250 and the bobbin 240 can be linked together without a spring through a first gear 292, a second gear 294, and a third gear 296.

[0090] The gear train 290 can be designed to rotate the bobbin 240 at a speed much faster than the rotational speed of the rotating shaft 250. Even if the rotational speed of the rotating shaft 250 is reduced, a strong parallel spring combination is formed to prevent the force from becoming weak, and the spring space can be further reduced compared to the conventional art by using the strong parallel spring combination.

[0091] As mentioned above, the present invention has been described with reference to a preferred embodiment. However, it will be understood that those skilled in the art can make various modifications and variations of the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. [Explanation of symbols]

[0092] 100 Tape measure 110 1st Housing 114 Cylinder hub 116 Housing cover 120 Second Housing 130 Blade 140 Bobbin 150 Rotation axis 160 Spring module 170 Spring 175 Additional Elastic Body 180 Spring housing 190 Gear train

Claims

1. Housing and a bobbin rotating within the housing; a blade wound on a winding surface of the bobbin and pulled out through an inlet of the housing or retrieved into the housing; and a spring module including a spring housing, a rotating shaft accommodated in the spring housing, and a spring connecting the spring housing and the rotating shaft; A tape measure, characterized in that the force of the spring is transmitted to the bobbin through the rotating shaft.

2. The spring housing includes a hollow cylinder portion inserted into the bobbin and a hollow disk portion integral with the cylinder portion and positioned on one side of the bobbin.

2. The tape measure of claim 1, wherein the rotating shaft axially passes through the cylinder portion and the disk portion of the spring housing to engage with the bobbin, the spring connects the spring housing and the rotating shaft at the disk portion, and the spring housing is fixed to the housing so that it cannot rotate about the center of the rotating shaft.

3. The housing is provided using a first housing covering one side of the bobbin where the disk portion is located and a second housing covering the other side of the bobbin, 3. The tape measure of claim 2, wherein the first housing includes a housing cover that covers the disk portion.

4. 4. The tape measure according to claim 3, further comprising a gear train interposed between the second housing and the bobbin for linking the rotating shaft and the bobbin, wherein a ratio of rotation of the bobbin to rotation of the rotating shaft by the gear train is greater than 1.

5. 5. The tape measure of claim 4, wherein the gear train includes a first gear that directly meshes with the rotating shaft, a second gear that is attached to the second housing and meshes with the first gear, and a third gear that meshes with the second gear to transmit rotation to the bobbin, the second gear being fixed to the second housing.

6. 3. The tape measure of claim 2, wherein the cylinder portion rotatably supports an inscribed surface of the bobbin.

7. 4. The tape measure of claim 3, wherein the first housing includes a hollow cylinder hub that rotatably supports an inscribed surface of the bobbin, and the cylinder portion is inserted into the cylinder hub.

8. 3. The tape measure according to claim 2, wherein a space is formed between the cylinder portion and the rotating shaft.

9. 9. The tape measure according to claim 8, wherein the ratio of the wound mirror of the bobbin to the outer diameter of the rotating shaft is 200 to 600%.

10. The rotary shaft further includes an additional elastic body that connects the cylindrical portion and the rotary shaft.

9. The tape measure according to claim 8, wherein the spring and the additional elastic body are wound in the same direction.

11. 11. The tape measure according to claim 10, wherein the thickness of the spring is greater than the thickness of the additional elastic body.

12. The tape measure according to claim 11, characterized in that the thickness of the spring is 2 to 4 times the thickness (Ti) of the additional elastic body.

13. The tape measure according to claim 10, wherein the width of the additional elastic body is 2 to 5 times wider than the width of the spring.

14. 3. The tape measure of claim 2, wherein the maximum outer diameter of the disk portion is 60 to 95% of the maximum outer diameter of the bobbin.

15. 3. The tape measure of claim 2, wherein the axle includes a flange that separates the cylinder portion from the disk portion.

16. 3. The tape measure of claim 2, wherein the spring housing includes a slit formed in a side surface of the disk portion, and one end of the spring is fastened to the slit.

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