Limiting device and tightening gun comprising same

Abstract

The utility model provides a limiting device, which is configured to be mounted on a tightening gun to limit the number of rotation turns of a rotating shaft of the tightening gun, and is characterized in that the limiting device comprises a cable with a preset effective length, and the effective length of the cable limits the number of rotation turns of the rotating shaft of the tightening gun. The first end of the cable is configured to be fixed on a fixed part of the tightening gun, and the second end of the cable is configured to be fixed on a rotating shaft of the tightening gun or a component capable of rotating together with the rotating shaft. The utility model further provides a tightening gun comprising the limiting device. According to the limiting mechanism and the tightening gun comprising the limiting mechanism, when a plurality of bolts are pre-tightened, consistent pre-tightening can be achieved.

Description

Technical Field

[0001] The utility model relates to the field of bolt pre-tightening, in particular to a tightening gun with a limiting function. Background Art

[0002] In industrial production, it is often necessary to tighten or pre-tighten multiple bolts or screws, and a tightening gun is usually used for tightening or pre-tightening.

[0003] A tightening gun is an electric tool that is often used in assembly operations. It can tighten bolts at a certain set torque through the motor. It is widely used in production because of its high reliability, good repeatability, ability to meet tightening process requirements, and ability to reduce workers' labor intensity. Tightening guns usually judge whether the bolts are tightened by the increase in torque. When the torque increases sharply, it is considered that the bolts are tightened in place and the tightening gun stops working.

[0004] In the automobile manufacturing industry, such as in automobile assembly lines, a large number of bolts or screws need to be tightened, and even if a tightening gun is used to tighten these bolts or screws, it takes a lot of time. In order to improve production efficiency, for example, on an automobile assembly line, when a car body or any other automobile part (workpiece) with a large number of bolts that need to be tightened is transferred between two stations, a tightening gun is used to pre-tighten these bolts, that is, not tightened in place, for example, the bolts are 2mm away from the bottom of the threaded hole, and then fully tightened in the next station or subsequent stations. This method uses the transfer time of the workpiece between stations to pre-tighten the bolts, thereby reducing the time occupied by the tightening of the bolts in the beat cycle of the production line and improving the efficiency of the production line.

[0005] When the pre-tightening method is used, since the bolt is not fully tightened, or even a certain distance away from the bottom of the threaded hole, the torque of the tightening gun will not increase significantly until it stops working. Therefore, in pre-tightening, the tightening gun user usually judges the pre-tightening degree of the bolt based on experience, and then fully tightens the bolt in the next workstation based on the torque signal of the tightening gun. That is, when the bolt is fully tightened, the further tightening torque will increase sharply, and when the torque exceeds the value set by the user, the tightening gun stops.

[0006] In the above method, since the pre-tightening degree of the bolt needs to be judged based on the experience of the tightening gun user, the pre-tightening depth of the bolt is inconsistent, which is prone to cause the following problems in practice:

[0007] 1. The final tightening of the bolts is inconsistent;

[0008] 2. For bolts that have been tightened in place during the pre-tightening process, they need to be loosened first and then tightened in place, which reduces the production efficiency of the corresponding workstation;

[0009] 3. There is a risk of errors in the tightening process, which increases maintenance time and reduces the production efficiency of the corresponding workstation;

[0010] 4. There is a risk of tightening failure;

[0011] 5. There is a risk of bolt breakage due to over-torque. Utility Model Content

[0012] In order to solve the above technical problems existing in the prior art, a limiting device of the present invention and a tightening gun including the limiting device are provided.

[0013] According to an object of the utility model, a limiting device and a tightening gun including the limiting device are provided, which can make the tightening depth of the bolt in the threaded hole substantially consistent.

[0014] According to another object of the utility model, a limiting device and a tightening gun including the limiting device are provided, which can be used to modify an existing tightening gun and has a simple structure and is easy to use.

[0015] According to another object of the present utility model, a limiting device and a tightening gun including the limiting device are provided, which do not affect the anti-loosening operation of the tightening gun.

[0016] The utility model provides a limiting device, which is configured to be installed on a tightening gun to limit the number of rotations of a rotating shaft of the tightening gun. It is characterized in that the limiting device comprises a cable with a predetermined effective length, the effective length of the cable limits the number of rotations of the rotating shaft of the tightening gun, the first end of the cable is configured to be fixed on a fixed part of the tightening gun, and the second end of the cable is configured to be fixed on the rotating shaft of the tightening gun or a component that can rotate with the rotating shaft.

[0017] Preferably, at least one end of the cable is fixed in a detachable manner.

[0018] Preferably, it further comprises a cable storage mechanism, which is fixed to the fixed part of the tightening gun, the first end of the cable is fixed in the cable storage mechanism, and the second end of the cable can extend from the cable storage mechanism or retract toward the cable storage mechanism.

[0019] Preferably, the cable storage mechanism includes: an elastic component, the first end of the cable is fixed on one end of the elastic component; and a fixed spool, the other end of the elastic component is fixed on the spool, the cable can be wound on the spool under the action of the elastic component, and the cable can overcome the elastic force of the elastic component and unfold from the spool under the action of external force.

[0020] Preferably, the elastic component is a coil spring.

[0021] Preferably, the cable storage mechanism is configured to be fixed on a handle or a shaft seat of the tightening gun.

[0022] Preferably, the cable storage mechanism can be fixed on the fixing part of the tightening gun by a clamp.

[0023] Preferably, it further comprises a winding sleeve, which is fixed to the rotating shaft of the tightening gun or a component that can rotate with the rotating shaft so that it can rotate with the rotating shaft, and the cable can be wound on the winding sleeve when the rotating shaft rotates.

[0024] Preferably, the second end of the cable is fixed to the winding sleeve.

[0025] Preferably, the second end of the cable is detachably fixed to the winding sleeve.

[0026] Preferably, the winding sleeve comprises a hole, the second end of the cable forms a ring-shaped portion through a fastener, the ring-shaped portion directly passes through the hole of the sleeve and is connected to the winding sleeve, or the ring-shaped portion is connected to a ring passing through the hole and is connected to the sleeve, wherein the fastener and / or the ring are openable.

[0027] Preferably, the distal end of the winding sleeve comprises a notch, through which the cable passes, thereby facilitating the wire rope to be wound around the winding sleeve when the rotating shaft of the tightening gun rotates.

[0028] Preferably, the notch is an elongated notch extending along the axial direction of the winding sleeve, so as to facilitate the cable to remain passing through the notch.

[0029] Preferably, the winding sleeve comprises two concentric parts: an inner sleeve for being fixed on a rotating shaft of the tightening gun or a part that can rotate together with the rotating shaft; and an outer sleeve detachably fixedly connected to the inner sleeve.

[0030] Preferably, the limiting device comprises a group of outer sleeves, each of which can be connected to the inner sleeve, and the outer sleeves are interchangeable and have different outer diameters.

[0031] Preferably, the inner sleeve is threadedly connected to the outer sleeve, wherein the thread tightening direction of the inner sleeve and the outer sleeve is opposite to the forward rotation direction of the rotating shaft of the tightening gun for tightening the bolt, so that the inner sleeve and the outer sleeve will not be loosened from each other when the cable is unfolded on the winding sleeve.

[0032] Preferably, the winding sleeve comprises two concentric parts: an inner sleeve fixed to the rotating shaft of the tightening gun or a part that can rotate with the rotating shaft; and an outer sleeve detachably fixedly connected to the inner sleeve, and the hole is formed on the outer sleeve.

[0033] Preferably, the winding sleeve comprises two concentric parts: an inner sleeve fixed to the rotating shaft of the tightening gun or a part that can rotate with the rotating shaft; and an outer sleeve detachably fixedly connected to the inner sleeve, and the notch is formed on the outer sleeve.

[0034] Preferably, when the actual length of the cable is greater than the effective length, an excess length of the cable is wound around a rotating shaft of the tightening gun or a component rotatable with the rotating shaft at the second end of the cable.

[0035] Preferably, when the actual length of the cable is greater than the effective length, a stopper is provided at the first end of the cable, and the cable storage mechanism is provided with a stop component cooperating with the stopper, thereby limiting the length of the cable that can extend from the cable storage mechanism.

[0036] The utility model also provides a tightening gun, comprising: a handle part, a motor is accommodated in the handle part, the handle part also includes a direction selection switch, and the direction selection switch can be pushed in two directions; a rotating shaft, which can rotate under the drive of the motor; an axle seat, extending from the handle part, and used to support the rotating shaft; an extension rod, which is installed on the rotating shaft and rotates together with the rotating shaft; an output head, which is installed at the end of the extension rod and is used to engage with the head of a bolt to be tightened, and apply the torque output by the motor via the rotating shaft and the extension rod to the bolt; a motor switch, which is used to start and stop the motor, the tightening gun also includes a torque sensor, and a torque setting mechanism is arranged on the axle seat, which is used to set the maximum output torque of the tightening gun, when the actual torque measured by the torque sensor exceeds the set maximum output torque, the motor switch is closed, and it is characterized in that the tightening gun includes the limiting mechanism according to the above.

[0037] Preferably, when the direction selection switch is activated in a first direction, the rotating shaft can rotate in a positive direction, thereby tightening the bolts matched with the output head in the corresponding threaded holes; when the direction selection switch is activated in a second direction opposite to the first direction, the rotating shaft can rotate in a reverse direction, thereby loosening the bolts matched with the output head in the corresponding threaded holes.

[0038] Preferably, the cable storage mechanism of the limiting mechanism is fixed on the shaft seat of the tightening gun by a clamp.

[0039] The limiting mechanism of the utility model and the tightening gun including the limiting mechanism can achieve consistent pre-tightening when pre-tightening multiple bolts, that is, when the effective length of the cable is fixed, the tightening gun with the limiting device according to the utility model can pre-tighten multiple bolts inwardly to the same depth in the corresponding threaded holes. In addition, the limiting mechanism of the utility model is applicable to most existing tightening guns, has a simple structure, is easy to install, and does not affect the anti-loosening function of the tightening gun. The use of the tightening gun including the limiting mechanism is not affected by the user's experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] After reading the following detailed description in conjunction with the accompanying drawings, various aspects of the present application will be better understood, in which:

[0041] Figure 1 A perspective view of a tightening gun is shown;

[0042] Figure 2 The limiting device according to the present application is shown Figure 1 An assembly diagram of a tightening gun is shown;

[0043] Figure 3 An exploded view of the cable storage mechanism of the limiting device according to the present application is shown;

[0044] Figure 4 An exploded perspective view showing a winding sleeve of the limiting device according to the present application; and

[0045] Figure 5 Show Figure 4 The winding sleeve is shown in an assembled view, and the second end of the cable is shown to be fixed on the winding sleeve, wherein the rotating shaft of the tightening gun on which the portion of the cable is wound is omitted.

[0046] Description of Reference Numerals

[0047] 1—limiting device 2—cable 22—second end

[0048] 221—ring buckle 3—cable storage mechanism 31—housing

[0049] 311—hole 4—fixture 41—plane

[0050] 5—winding sleeve 51—inner sleeve 52—outer sleeve

[0051] 521 - hole 522 - gap 6 - ring

[0052] 7—Fasteners

[0053] 100 - tightening gun 101 - handle 102 - shaft seat

[0054] 1021 - torque setting mechanism 103 - rotating shaft 104 - output head

[0055] 105—Direction selection switch 106—Extension rod DETAILED DESCRIPTION

[0056] The technical solution of the utility model will be clearly and completely described below in conjunction with the accompanying drawings and specific implementation methods, but those skilled in the art will understand that the embodiments described below are part of the embodiments of the utility model, rather than all of the embodiments, and are only used to illustrate the utility model, and should not be regarded as limiting the scope of the utility model. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0057] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0058] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] Figure 1A tightening gun 100 for tightening bolts is shown. The tightening gun 100 of the prior art generally includes: a handle portion 101, in which a motor (not shown) is accommodated, and the handle portion 101 also includes a direction selection switch 105, and the direction selection switch 105 can be pushed in two directions; a rotating shaft 103, which rotates under the drive of the motor; an axle seat 102, extending from the handle 101 portion, for supporting the rotating shaft 103, and a torque setting mechanism 1021 can be provided on the axle seat 102, for setting the maximum output torque of the tightening gun, when the actual torque exceeds the maximum output torque, the motor stops working; and a motor switch (not shown), which can be external to the tightening gun, and can also be built into the tightening gun. For example, in Figure 1 and 2 In the tightening gun shown in , the motor switch is built into the tightening gun 101, and is started when the rotating shaft is subjected to axial pressure, and is closed when the starting pressure is removed. For example, the motor switch is started when the tightening gun 100 is pressed against the bolt to be tightened with a certain pressure, and the motor switch is closed when the tightening gun is lifted. Preferably, the tightening gun 100 also includes: an extension rod 106, which is installed on the rotating shaft 103 and rotates together with the rotating shaft; and an output head 104, which is installed at the end of the extension rod 106 and is used to engage with the head of the bolt to be tightened, and apply the torque transmitted by the rotating shaft 103 and the extension rod 106 to the bolt. Wherein, the tightening gun 100 also includes a torque sensor (not shown) for measuring the torque output by the output head 104. As described above, when the measured torque is greater than the maximum output torque, the motor switch stops. When the direction selection switch 105 is pushed in the forward direction, the rotating shaft 103 and the extension rod 106 can rotate forward when the motor switch is started, thereby tightening the bolts matched with the output head 104 in the corresponding threaded holes; when the direction selection switch 105 is pushed in the reverse direction, the rotating shaft 103 and the extension rod 106 can rotate reversely when the motor switch is started, thereby loosening the bolts matched with the output head 104 in the corresponding threaded holes. This process is called reverse loosening.

[0060] According to the utility model, the limiting device 1 is installed on the tightening gun 100, and the limiting device 1 is used to limit the number of rotations of the rotating shaft 103 and the extension rod 106 of the tightening gun 100, thereby limiting the screwing depth of the tightening gun 100 in tightening the bolt in the corresponding threaded hole.

[0061] The limiting device 1 according to the utility model comprises: a cable 2 with a certain effective length, the effective length of the cable 2 limits the number of rotations of the rotating shaft 103 and the extension rod 106 of the tightening gun 100, the first end of the cable 2 is fixed to the fixed part of the tightening gun 100, for example, fixed to the handle 101 or the shaft seat 102 of the tightening gun 100, and the second end of the cable 2 is fixed to the rotating shaft 103 or the extension rod 106 of the tightening gun 100. The effective length of the cable 2 is the total length of the cable 2 that can be wound around the rotating shaft 103 and the extension rod 106 during the rotation of the rotating shaft 103 of the tightening gun 100, and the effective length limits the number of rotations of the rotating shaft 103 and the extension rod 106 of the tightening gun 100, thereby limiting the depth of the bolt being screwed into the threaded hole.

[0062] Therefore, when the direction selection switch 105 of the tightening gun 100 is pushed in the forward direction and the motor switch is activated, the rotating shaft 103 rotates in the forward direction. Since the first end of the cable 2 is fixed and the second end is fixed to the extension rod 106 and rotates together with the extension rod 106, the cable 2 is wound around the extension rod 106. After the entire effective length of the cable 2 is wound around the extension rod 106, the cable 2 will limit the further rotation of the rotating shaft 103 and the extension rod 106, so the output torque of the tightening gun 100 increases sharply. When the output torque is greater than the maximum output torque set by the user through the torque setting mechanism 1021, the motor switch is turned off and the motor stops working. Then, the user can push the direction selection switch 105 of the tightening gun 100 in the reverse direction and start the motor switch to make the rotating shaft 103 rotate in the reverse direction, so that the cable 2 wound on the extension rod 106 will be unrolled from the extension rod 106. When the entire effective length of the cable 2 is unrolled from the extension rod 106, the user can turn off the motor switch.

[0063] The cable is flexible and can be wound around the rotating shaft and the extension rod of the tightening gun. The cable can be made of a material that can withstand a large tensile force, such as nylon, metal wire or other materials that can withstand a large tensile force. The cable can also be made of an elastic material.

[0064] As described above, the effective length of the cable 2 defines the number of rotations of the rotating shaft 103 of the tightening gun 100, that is, the depth to which the tightening gun 100 screws the bolt into the corresponding threaded hole. Therefore, in the pre-tightening operation of the bolt, the effective length of the cable 2 is set to be insufficient to allow the bolt to be completely tightened in the corresponding threaded hole. In addition, in order to adjust the effective length of the cable 2, preferably, at least one end of the cable 2 is fixed in a detachable manner. When it is necessary to shorten the effective length of the cable 2, one end of the cable 2 is opened, the excess cable length is wound around the extension rod 106 of the tightening gun 100, and then the detachable end of the cable 2 is re-fixed.

[0065] Preferably, the limiting device 1 according to the present invention further comprises a cable storage mechanism 3, the cable 2 can extend from the cable storage mechanism 3 and can be stored in the cable storage mechanism 3, preferably, the cable storage mechanism 3 can also make the cable tensioned. The cable storage mechanism 3 is fixed to the fixed part of the tightening gun 100, for example, fixed to the handle 101 or the shaft seat 102 of the tightening gun 100. Figure 3 An example of the cable storage mechanism 3 is shown.

[0066] Preferably, the cable storage mechanism 3 comprises: a housing 31; an elastic component, such as a coil spring or a spiral spring, contained in the housing 31, the first end of the cable 2 is fixed to one end of the coil spring; and a bobbin contained in the housing 31, the other end of the coil spring is fixed to the bobbin, and the cable 2 can be wound on the bobbin or unwound from the bobbin. When the tightening gun is started and rotates forward, the cable 2 is wound on the extension rod of the tightening gun from the vicinity of the second end, and the cable 2 is continuously pulled out of the housing 31 against the elastic force of the elastic component, and the elastic component is elastically deformed in the process; when the tightening gun 100 is lifted and the motor switch of the tightening gun 100 stops, that is, when no external force continues to be applied to the cable 2 to make it wind on the extension rod, the elastic component can make the cable 2 wind onto the bobbin in the cable storage mechanism 3 through elastic force.

[0067] refer to Figure 2 and Figure 3 Preferably, the cable storage mechanism 3 is fixed to the shaft seat 102 of the tightening gun 100 by a clamp 4. The clamp 4 includes two parts connected together by screws. Preferably, the clamp 4 includes at least one flat surface 41 at a position where it contacts the shaft seat 102 of the tightening gun 100, thereby preventing the clamp 4 from rotating around the shaft seat 102.

[0068] Preferably, the limiting device 1 according to the present invention further comprises a winding sleeve 5, the diameter of the winding sleeve 5 is larger than the diameter of the extension rod 106 of the tightening gun 100, and the winding sleeve 5 is fixed to the extension rod 106 of the tightening gun 100, so that it can rotate together with the extension rod 106, so that the cable 2 can be wound on the winding sleeve 5 when the extension rod 106 rotates. In this embodiment, the effective length of the cable 2 is the entire length of the cable 2 that can be wound on the winding sleeve 5 during the rotation of the rotation shaft 103 of the tightening gun 100, and the effective length limits the number of rotations of the rotation shaft 103 of the tightening gun 100, and thus limits the depth to which the bolt is screwed into the threaded hole.

[0069] like Figure 4 As shown in the exploded view, preferably, the winding sleeve 5 includes two concentric parts: an inner sleeve 51 fixed on the extension rod 106 of the tightening gun 100; and an outer sleeve 52 detachably fixedly connected to the inner sleeve 51, so that the outer sleeve 52 of different diameters can be replaced to adjust the torque for recovering the cable 2, which will be described in detail below.

[0070] Preferably, the inner sleeve 51 is threadedly connected to the outer sleeve 52, wherein the thread tightening direction of the inner sleeve 51 and the outer sleeve 52 is opposite to the forward rotation direction of the rotating shaft 103 of the tightening gun 100, so that the inner sleeve 51 and the outer sleeve 52 will not be loosened from each other when the cable 2 is unwound from the winding sleeve 5.

[0071] Preferably, the second end 22 of the cable 2 is fixed to the winding sleeve 5. More preferably, the second end 22 of the cable 2 is detachably fixed to the winding sleeve 5. Therefore, when the actual length of the cable 2 is greater than the required effective length, the second end of the cable is opened and the excess length is wound around the extension rod 106 of the tightening gun 100 (e.g., Figure 2 , Figure 5 As shown, Figure 5 The middle extension rod is omitted), and then the second end 22 of the cable 2 is fixed to the winding sleeve 5 again.

[0072] Figure 5 An example is shown, in which the second end 22 of the cable 2 is detachably fixed to the winding sleeve 5, wherein the rotating shaft of the tightening gun on which the portion of the cable is wound is omitted. Figure 5The winding sleeve 5 includes a hole 521, and the second end 22 of the cable 2 forms a ring portion 221 through an openable fastener 7. The ring portion can directly pass through the hole 521 of the sleeve 5 to be connected to the winding sleeve 5, or can be connected to the ring 6 passing through the hole 521 as shown in the figure, so as to be connected to the sleeve 5. In the above embodiment, the fastener 7 is openable, and alternatively or additionally, the ring 6 is an openable ring. Preferably, the hole 521 is formed on the outer sleeve 52.

[0073] Still refer to Figure 5 In the embodiment shown, preferably, the distal end of the winding sleeve 5 includes a notch 522, through which the cable passes, for fixing the starting position of the cable 2 on the winding sleeve 5, which is conducive to the cable 2 being wound on the winding sleeve 5 when the rotating shaft 103 of the tightening gun 100 rotates. Preferably, the notch 522 has an elongated shape extending along the winding sleeve 5, so as to facilitate the cable 2 to remain passing therethrough. Preferably, the notch 522 is formed on the outer sleeve 52.

[0074] The following is Figure 2 The preferred embodiment of the present invention is shown as an example to illustrate the working process of the limiting device 1 of the present invention.

[0075] First, the effective length of the cable 2 of the stopper 1 is determined according to the pre-tightening depth of the bolts in the corresponding threaded holes. For example, if a batch of bolts need to be pre-tightened to a distance of 2 mm from the bottom of the corresponding threaded holes, the effective length of the cable 2 is calculated according to the number of turns of the bolts required and the diameter of the outer sleeve 52 of the winding sleeve 5 of the stopper 1 selected.

[0076] If the actual length of the cable 2 is greater than the calculated effective length, the fastener 7 at the second end 22 of the cable 2 is opened, the second end 22 of the cable 2 is taken out of the ring 6, and the excess length of the cable 2 is wound around the extension rod 106 of the tightening gun 100, as shown in FIG. Figure 2 , Figure 5As shown, the fastener 7 is then closed to fix the second end 22 of the cable 2 on the ring 6, wherein the ring 6 is connected to the hole 521 of the winding sleeve 5, and the cable 22 passes through the notch 522 provided at the distal end of the winding sleeve 5 and is wound around the extension rod 106 of the tightening gun 100. It is also conceivable that a stopper is provided at the first end of the cable 2, and a matching stopper is provided on the cable storage mechanism 3 to cooperate with the stopper of the cable 2, thereby limiting the total length of the cable 2 extending from the cable storage mechanism 3. For example, a knot is tied at the first end of the cable 2 according to the required effective length, and the diameter of the formed cable knot is larger than the hole 311 (see FIG. 2 ) on the outer shell of the cable storage mechanism 3 through which the cable 2 passes. Figure 3 ) in diameter, so that the cable between the cable knot and the first end cannot extend from the cable storage mechanism 3 through the hole 311 on the shell.

[0077] Then, the maximum output torque of the tightening gun 100 is set by the torque setting mechanism 1021 .

[0078] Next, the direction selection switch 105 is pushed forward and the motor switch is started, so that the rotating shaft 103 rotates forward, and the torque output by the rotating shaft 103 tightens the bolts to be pre-tightened in the corresponding threaded holes. In this process, since the winding sleeve 5 is fixed on the extension rod 106, the cable 2 is wound around the winding sleeve 5 as the rotating shaft 103 and the extension rod 106 rotate, and as the cable 2 is pulled out of the housing 31 of the cable storage mechanism 3, the winding spring in the cable storage mechanism 3 gradually deforms, and the cable 2 is tensioned.

[0079] When the bolt is tightened to a predetermined pre-tightening degree, for example, 2 mm from the bottom of the threaded hole, the effective length of the cable 2 is completely extended from the housing 31 of the cable storage mechanism 3, and the cable 2 stops extending from the housing 31, so the output torque of the tightening gun 100 will increase sharply. When the output torque is greater than the maximum output torque set by the user, the motor switch is turned off, and the rotating shaft 103 of the tightening gun 100 stops rotating. Therefore, the effective length of the cable 2 can limit the number of rotations of the rotating shaft 103.

[0080] At this time, the user can lift the tightening gun 100 away from the pre-tightened bolt. The elastically deformed coil spring in the cable storage mechanism 3 begins to recover its shape, and the force applied to the cable 2 is applied to the side wall of the outer sleeve 52 of the winding sleeve 5 through the cable 2 at the notch 522 of the winding sleeve 5. The force and the radius of the winding sleeve 5 form a certain torque, which can cause the winding sleeve 5 to rotate in the reverse direction, so that the cable 2 is unwound from the winding sleeve 5 and retracted into the housing 31 of the cable storage mechanism 3 under the elastic force of the coil spring.

[0081] Therefore, the larger the radius of the winding sleeve 5, that is, the radius of the outer sleeve 5, the larger the torque that can be generated by the force exerted by the coil spring in the cable storage mechanism 3 on the outer sleeve 52, and the easier it is to rotate the winding sleeve 5. Therefore, when the elastic force exerted by the coil spring is constant, the outer sleeves 52 of different diameters can be replaced to adjust the recovery speed of the cable 2.

[0082] In addition, when the pre-tightened bolt needs to be reversed loosened, that is, when the direction selection switch of the tightening gun is used to allow the rotating shaft to rotate in the opposite direction, the limiting mechanism of the utility model will not affect the reverse loosening function of the tightening gun.

[0083] It can be seen from the above description of the specific embodiments that the position limiting mechanism of the utility model and the tightening gun including the position limiting mechanism can achieve consistent pre-tightening when pre-tightening multiple bolts, that is, when the effective length of the cable is fixed, the tightening gun with the position limiting device according to the utility model can screw multiple bolts inwardly to the same depth in the corresponding threaded holes. Therefore, the position limiting mechanism of the utility model and the tightening gun including the position limiting mechanism can achieve the following technical effects:

[0084] 1. It can avoid over-tightening and bolt cracking during pre-tightening;

[0085] 2. Avoid being identified as repeated tightening in the normal tightening step after pre-tightening, resulting in insufficient tightening of the bolts;

[0086] 3. Reduce or even avoid the troubleshooting time in the pre-tightening step and the subsequent normal tightening step, and reduce the scrap rate;

[0087] 4. Reduce the tightening failure rate;

[0088] 5. Improve the stability of pre-tightening quality.

[0089] In addition, the use of the limit device will not increase the user's operation time, nor will it add extra steps; the use of the limit device is not affected by the user's experience and is applicable to most existing tightening guns, has a simple structure, and is easy to install; the limit device does not affect the anti-loosening function of the tightening gun.

[0090] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0091] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. The technicians in this industry should understand that the utility model is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model will have various changes and improvements, and these changes and improvements fall within the scope of the utility model to be protected.

Claims

1. A limit device, which is configured to be installed on a tightening gun to limit the number of rotations of a rotating shaft of the tightening gun, characterized in that: The limiting device includes a cable with a predetermined effective length, the effective length of the cable limits the number of rotations of the rotating shaft of the tightening gun, the first end of the cable is configured to be fixed to the fixed part of the tightening gun, and the second end of the cable is configured to be fixed to the rotating shaft of the tightening gun or a component that can rotate with the rotating shaft.

2. The limiting device according to claim 1, characterized in that: At least one end of the cable is fixed in a detachable manner.

3. The limiting device according to claim 1, characterized in that: It also includes a cable storage mechanism, which is fixed to the fixed part of the tightening gun, the first end of the cable is fixed in the cable storage mechanism, and the second end of the cable can be extended from the cable storage mechanism or retracted toward the cable storage mechanism.

4. The limiting device according to claim 3, characterized in that: The cable storage mechanism comprises: an elastic member, the first end of the cable being fixed to one end of the elastic member; and A fixed bobbin, the other end of the elastic component is fixed on the bobbin, the cable can be wound on the bobbin under the action of the elastic component, and the cable can overcome the elastic force of the elastic component under the action of external force and be unfolded from the bobbin.

5. The limiting device according to claim 4, characterized in that: The elastic component is a coil spring.

6. The limiting device according to any one of claims 3 to 5, characterized in that: The cable storage mechanism is configured to be fixed on a handle or a shaft seat of the tightening gun.

7. The limiting device according to claim 6, characterized in that: The cable receiving mechanism can be fixed on the fixed part of the tightening gun by a clamp.

8. The limiting device according to any one of claims 1 to 5, characterized in that: It also includes a winding sleeve, which is fixed to the rotating shaft of the tightening gun or a component that can rotate with the rotating shaft, so that it can rotate with the rotating shaft, and the cable can be wound on the winding sleeve when the rotating shaft rotates.

9. The limiting device according to claim 8, characterized in that: The second end of the cable is fixed to the winding sleeve.

10. The limiting device according to claim 9, characterized in that: The second end of the cable is detachably fixed to the winding sleeve.

11. The limiting device according to claim 10, characterized in that: The winding sleeve comprises a hole, the second end of the cable forms a ring portion through a buckle, the ring portion directly passes through the hole of the sleeve and is connected to the winding sleeve, or the ring portion is connected to a ring passing through the hole and is connected to the sleeve, wherein the buckle and / or the ring are openable.

12. The limiting device according to claim 8, characterized in that: The distal end of the winding sleeve includes a notch through which the cable passes.

13. The limiting device according to claim 12, characterized in that: The notch is an elongated notch extending along the axial direction of the winding sleeve.

14. The limiting device according to claim 8, characterized in that: The winding sleeve comprises two concentric parts: an inner sleeve for being fixed on the rotating shaft of the tightening gun or a part that can rotate together with the rotating shaft; and an outer sleeve that is detachably fixed to the inner sleeve.

15. The limiting device according to claim 14, characterized in that: The limiting device comprises a group of outer sleeves, each of which can be connected to the inner sleeve, and each outer sleeve is interchangeable and has different outer diameters.

16. The limiting device according to claim 14 or 15, characterized in that: The inner sleeve is threadedly connected to the outer sleeve, wherein the thread tightening direction of the inner sleeve and the outer sleeve is opposite to the forward rotation direction of the rotating shaft of the tightening gun for tightening the bolt.

17. The limiting device according to claim 11, characterized in that: The winding sleeve comprises two concentric parts: an inner sleeve fixed on the rotating shaft of the tightening gun or a part that can rotate with the rotating shaft; and an outer sleeve detachably fixedly connected to the inner sleeve, and the hole is formed on the outer sleeve.

18. The limiting device according to claim 12 or 13, characterized in that: The winding sleeve comprises two concentric parts: an inner sleeve fixed on the rotating shaft of the tightening gun or a part that can rotate with the rotating shaft; and an outer sleeve detachably fixedly connected to the inner sleeve, and the notch is formed on the outer sleeve.

19. The limiting device according to claim 1, characterized in that: When the actual length of the cable is greater than the effective length, the excess length of the cable is wound around the rotating shaft of the tightening gun or a component that can rotate together with the rotating shaft at the second end of the cable.

20. The limiting device according to claim 3, characterized in that: When the actual length of the cable is greater than the effective length, a stopper is provided at the first end of the cable, and the cable storage mechanism is provided with a stop component cooperating with the stopper, thereby limiting the length of the cable that can extend from the cable storage mechanism.

21. A tightening gun, comprising: a handle portion in which the motor is housed, the handle portion also comprising a direction selection switch capable of being pushed in two directions; A rotating shaft, which can rotate under the driving of the motor; an axle seat extending from the handle portion and used to support the rotating shaft; An extension rod, mounted on the rotating shaft and rotating together with the rotating shaft; An output head, mounted at the end of the extension rod, for engaging with the head of a bolt to be tightened, and applying the torque output by the motor and transmitted via the rotating shaft and the extension rod to the bolt; a motor switch for starting and stopping the motor, The tightening gun also includes a torque sensor, and a torque setting mechanism is arranged on the shaft seat for setting the maximum output torque of the tightening gun. When the actual torque measured by the torque sensor exceeds the set maximum output torque, the motor switch is turned off. Characterized in that the tightening gun comprises a limiting device according to any one of claims 1-20.

22. The tightening gun according to claim 21, characterized in that When the direction selection switch is activated in a first direction, the rotating shaft can rotate in a positive direction, thereby tightening the bolts matched with the output head in the corresponding threaded holes; when the direction selection switch is activated in a second direction opposite to the first direction, the rotating shaft can rotate in a reverse direction, thereby loosening the bolts matched with the output head in the corresponding threaded holes.

23. The tightening gun according to claim 21 or 22, characterized in that: The cable storage mechanism of the limiting device is fixed on the shaft seat of the tightening gun through a clamp.

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