Ratchet wheel self-locking measuring tape

Abstract

The utility model discloses a ratchet wheel self-locking measuring tape, which comprises a shell, a button, a pawl, a ratchet wheel and a winding drum, the shell is divided into an upper shell and a lower shell; the winding drum is mounted on the lower shell and is used for mounting and limiting the coil spring; the ratchet wheel is installed on the winding drum, rotates along with the winding drum and is used for limiting rotation of the winding drum. The pawl and the button are installed on the upper shell, and the functions that the ratchet wheel is loosened by pressing the button to extrude the pawl and the button is loosened to clamp the ratchet wheel are achieved. Rotation and locking of the winding drum are controlled through the ratchet wheel and the pawl, so that clamping and withdrawing of a tape strip of the measuring tape are achieved.

Description

Technical Field

[0001] This utility model relates to the field of engineering surveying, and in particular to a self-locking measuring tape. Technical Background

[0002] Measuring tapes have a wide range of applications in daily life and engineering. They are usually used to measure the length of objects. Measuring tapes are generally divided into mechanical measuring tapes and electric measuring tapes. Mechanical measuring tapes are generally inexpensive and use wedges to fix the tape strip. Although electric measuring tapes are more convenient to use, their production costs are too high. This product focuses on the durability of mechanical measuring tapes. Ordinary mechanical measuring tapes have low wedge strength and are easily damaged during use. Once the wedge is damaged, the tape strip cannot be locked, making it difficult for one person to use the measuring tape alone. In order to improve the lifespan and convenience of measuring tapes and make up for the shortcomings of measuring tapes when used by one person, a mechanical measuring tape that can be used by one person with one hand is needed. Utility Model Content

[0003] To overcome the above shortcomings, this utility model provides a ratchet self-locking tape measure. The technical solution of this utility model is as follows: a ratchet self-locking tape measure, comprising a button, an upper housing, a pin, a pawl, a ratchet, a drum, and a lower housing. The drum and ratchet are installed together via an interference fit and are mounted together on the lower housing. One end of a coil spring is wound around a cylinder, and the other end is clamped onto the drum. The drum rotates around the cylinder, and during installation, it should rotate several turns in the opposite direction of the coil spring force to provide pre-tension for retracting the tape. The pawl is installed on the upper housing via a pin or bolt connection and also serves to limit the button. The button is used to compress the pawl through external pressing, thereby locking and releasing the ratchet. A cylinder with a threaded hole is located at the center of the lower housing. A circular protrusion is also present on the lower housing, centered on the cylinder, to limit the movement of the drum. A threaded hole is drilled at the center of the upper housing for tightening the upper and lower housings together. Two holes, one large and one small, are drilled on the upper side of the upper housing. The larger hole is for mounting the button and is surrounded by a thin annular wall. The smaller hole is for mounting the pawl via a pin. Inside the upper housing, near the pawl mounting area, there is a hollow rectangular protrusion for mounting a spring to press the pawl, ensuring that the ratchet is locked when the button is not pressed, preventing the ratchet from retracting under the force of the spring. Both the upper and lower housing edges have interlocking thin-walled contours to ensure proper installation. Inside the outlet of the upper and lower housings, several trapezoidal protrusions support the arc-shaped ruler, preventing it from shifting during extension and retraction. A groove is provided on the lower side of the housing outlet to prevent interference between the ruler and the outlet when extended.

[0004] Compared with existing technologies, the advantages of this utility model are as follows: This utility model's ratchet self-locking measuring tape uses a spring to press the pawl, thus keeping it locked at all times during operation, eliminating the need for manual locking of the tape strip. This improves the lifespan and convenience of the measuring tape. Furthermore, this utility model's ratchet self-locking measuring tape allows the ratchet to be released by pressing a button; releasing the button at any time causes the pawl to re-lock the ratchet under the action of the spring, facilitating one-handed operation and improving product safety. Attached Figure Description

[0005] Figure 1 This is an exploded view of the ratchet self-locking mechanism proposed in this utility model;

[0006] Figure 2 This is a schematic diagram of the structure of a ratchet self-locking mechanism proposed in this utility model;

[0007] Figure 3 This is a schematic diagram of the button component proposed in this utility model;

[0008] Figure 4 This is a schematic diagram of the ratchet component proposed in this utility model;

[0009] Figure 5 This is a schematic diagram of the pawl component proposed in this utility model;

[0010] Figure 6 This is a schematic diagram of the components of the roll proposed in this utility model;

[0011] Figure 7 This is a schematic diagram of the lower housing component proposed in this utility model;

[0012] Figure 8 This is a schematic diagram of the upper housing component proposed in this utility model; Detailed Implementation

[0013] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0014] Please see Figure 1—8. This utility model provides a technical solution: a ratchet self-locking measuring tape, including a ratchet 4, a pawl 5, and a drum 6. The ratchet has a round hole 41 with a rectangular groove inside, which is interference-fitted with the outer protrusion 61 of the drum and installed together on the lower housing 1. The side 42 of the ratchet 4 cooperates with the pawl 5. A hollow rectangular protrusion 22 is provided in the upper part of the upper housing 2 near the installation of the pawl 5. The ratchet 4 is connected to the upper housing 2. The upper side of the upper housing 2 has two holes, one large 26 and one small 21. The large hole 26 is connected to the button 3, and the small hole 21 is used to install the pawl 5 by connecting it with a pin.

[0015] It should be added that the pawl 5 is installed on the upper housing 2 via a pin or bolt connection, and also serves to limit the movement of the button 3. The triangular pawl 53 and the pawl's inclined surface 51 contact the inverted boss 31 of the button 3 to achieve the clamping and releasing of the pawl 5, thereby locking and releasing the ratchet 4. This facilitates the user's one-handed operation and makes it safer and more stable.

[0016] It should be added that, with the cylinder as the center, there is a circular protrusion 13 on the lower housing 1, which contacts and limits the movement of the drum 6. A threaded hole 28 is drilled at the center of the upper housing 2 for tightening the upper housing 2 and the lower housing 1. This increases the stability of the overall structure of the measuring tape during use.

[0017] In a preferred embodiment, the pawl 5 is fixedly connected to a spring-loaded pawl engagement surface 53.

[0018] It should be added that a hollow rectangular protrusion 22 is provided inside the upper housing 2 near the upper part where the ratchet 5 is installed. This protrusion is used to install a spring to press the ratchet 5, ensuring that the ratchet 4 is locked when the button 3 is not pressed, preventing the ratchet 4 from retracting under the force of the coiling spring. This increases the smoothness of the retraction process, facilitates retraction, and ensures locking. Both the upper thin-shell protrusion 23 and the lower thin-shell protrusion 12 have a ring of thin-walled contours that can cooperate with each other, ensuring that the upper housing 2 and the lower housing 1 can be correctly installed. The upper trapezoidal protrusion 24 and the lower trapezoidal protrusion 14 support the arc-shaped ruler, ensuring that the ruler does not shift when pulled out and retracted. A groove 25 is provided on the lower side of the housing outlet to prevent the ruler from interfering with the outlet when pulled out. This increases the stability of the ruler strip and facilitates more efficient ruler extension.

[0019] Brief description of usage: During the self-locking process, simply extend the ruler strip to drive the pawl 5 into the groove of the ratchet 4 to complete the self-locking. There is no need to manually tighten the ruler strip, which improves the life of the measuring tape. During the tape return process, simply press the button 3. The button 3 will transmit force to the pawl 5, and the ratchet 4 will reverse to complete the tape return. Moreover, the whole process can be operated with one hand, which provides safety for the user.

[0020] The basic principles, main features, and advantages of this utility model are shown and described above. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A ratchet self-locking tape measure, characterized in that include: Lower housing (1), upper housing (2), button (3), ratchet (4), pawl (5), drum (6); the drum (6) and ratchet (4) are installed together by interference fit and are installed together on the lower housing (1), and the drum (6) is connected to the ruler; the pawl (5) is installed on the upper housing (2) by pin connection or bolt connection and contacts the button (3); the button (3) contacts the pawl (5) through the large hole (26) of the upper housing (2); The lower housing (1) has a non-closed cylinder (11) with a threaded hole at its center, which is used to tighten and install the upper and lower housings (1); one end of the coil spring is wound around the cylinder (11), and the other end is clamped on the drum (6), while the drum (6) rotates around the cylinder (11); with the cylinder (11) as the center, there is also a circular protrusion (13) on the lower housing (1) to limit the movement of the drum (6), and a screw is drilled at the center of the upper housing (2). The perforated hole (28) is used to tighten and install the upper and lower housings (1); there are two holes, one large and one small, on the upper side of the upper housing (2). The large hole (26) is used to install the button (3). At the same time, there is also a ring of thin wall around the large hole (26) to limit the button (3). The small hole (21) is used to install the pawl (5) by connecting it with a pin; a hollow rectangular protrusion (22) is provided on the upper part of the upper housing (2) near the installation of the pawl (5). The spring is installed and the pawl (5) is pressed to ensure that the ratchet (4) is locked when the button (3) is not pressed; there is a ring of thin wall contour on the edge of the upper housing (2) and the lower housing (1) that can be pressed against each other to ensure that the upper housing (2) and the lower housing (1) can be installed correctly. There are several lower trapezoidal protrusions (14) on the inner side of the outlet of the upper housing (2) and the lower housing (1). A groove (25) is provided on the lower side of the housing outlet. There are upper trapezoidal protrusions (24) and lower trapezoidal protrusions (14).

2. A ratchet self-locking tape measure according to claim 1, wherein, The upper housing has a large hole (26) and a small hole (21) on it. There is a hollow rectangular protrusion (22) inside the threaded hole (28) for installing the spring. The upper trapezoidal protrusion (24) is used to support the arc-shaped ruler. The outer edge has an upper thin shell protrusion (23) for installation with the lower housing (1).

3. A ratchet locking tape measure according to claim 1 wherein, The pawl has a triangular claw (53) at the front end and the pawl bevel (51) contacts the button (3).

4. A ratchet locking tape measure according to claim 1 wherein, The lower housing has a cylindrical (11) protrusion, an annular protrusion (13), a lower thin shell protrusion (12), and a lower trapezoidal protrusion (14) at its center; the lower thin shell protrusion (12) is used to clamp with the upper housing (2); the lower trapezoidal protrusion (14) is located at the rack outlet, and there is also an annular protrusion (13) that contacts the drum (6).

5. A ratchet locking tape measure according to claim 1 wherein, The ratchet (4) has a round hole (41) with a rectangular groove inside, which is used to cooperate with the outer protrusion (61) of the drum and perform circumferential positioning.

6. A ratchet locking tape measure according to claim 1 wherein, The roller has a cylinder on its upper side and a roller outer protrusion (61) on the outer side of the cylinder, which is used to cooperate with the round hole (41) of the ratchet rectangular groove and perform circumferential positioning.

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