Pre-tightening mechanism

Abstract

The utility model is suitable for the technical field of automation, and provides a pre-tightening mechanism which comprises a mounting plate, an elastic mounting seat is arranged on the mounting plate, a mounting cylinder is fixedly connected to the elastic mounting seat, and a bit is detachably arranged in the mounting cylinder. The elastic mounting seat comprises a rotating cylinder with an opening in the front end, a mounting sleeve, a bearing and a mounting column, a spring allowing the mounting column to stretch out and draw back is arranged in an inner cavity of the rotating cylinder, and the mounting cylinder is fixedly connected to the end of the mounting column. According to the pre-tightening mechanism, the screwdriver head capable of elastically stretching out and drawing back is arranged to abut against a bolt, the stepping motor drives the screwdriver head to rotate to pre-tighten the bolt, the spring screwdriver head is matched with the motor to easily align to the bolt, the screwdriver head makes flexible contact with the bolt, the pre-tightening depth can be adjusted, and the situation that tightening is too deep or too shallow is avoided; and meanwhile, the pre-tightening mechanism is not prone to being clamped and damaged in unexpected situations, and the efficiency and consistency of the bolt pre-tightening procedure can be improved.

Description

Technical Field

[0001] The utility model belongs to the field of automation technology, and in particular relates to a pre-tightening mechanism. Background Art

[0002] With the rapid development of industrial upgrading and cost reduction and efficiency improvement, manufacturing companies are gradually transforming towards automation and intelligentization. The proportion of automated production technology in production lines across various industries has increased year by year and has achieved significant development. At the same time, theories such as innovative mechanical design combined with electrical control applications have also been widely applied and put into practice.

[0003] Bolts and screws on various equipment and products require pre-tightening during installation. Traditionally, workers place the bolts into designated threaded holes and then manually tighten them with a screwdriver. Because the screwdriver bit is manually aligned, and the pre-tightening depth and torque are controlled manually, inconsistent pre-tightening torque can easily occur. This can lead to damage to parts due to over-loosening or over-close tightening, resulting in poor process consistency in actual production. Utility Model Content

[0004] The utility model provides a pre-tightening mechanism, which aims to solve the problem that when pre-tightening bolts, the pre-tightening depth and torque are entirely controlled by hand, which easily leads to inconsistent pre-tightening torque, resulting in excessive looseness or excessive closeness to damage parts.

[0005] The utility model is realized as follows: a pre-tightening mechanism comprises a mounting plate, an elastic mounting seat is provided on the mounting plate, a mounting cylinder is fixedly connected to the elastic mounting seat, and a screwdriver bit is detachably provided in the mounting cylinder;

[0006] The elastic mounting seat includes a rotating cylinder with an open front end, a mounting sleeve, a bearing, and a mounting post. The mounting sleeve is fixedly connected to the mounting plate. The rotating cylinder is rotatably arranged inside the mounting sleeve via a bearing. The rear end of the mounting post is telescopically arranged in the inner cavity of the rotating cylinder. The inner cavity of the rotating cylinder is provided with a spring for the expansion and contraction of the mounting post. The mounting cylinder is fixedly connected to the end of the mounting post.

[0007] A stepping motor for driving the rotating cylinder to rotate is arranged on the mounting plate.

[0008] Preferably, a through hole is provided on the mounting plate, the rear end of the rotating cylinder passes through the mounting sleeve, the bearing and the through hole and extends to the rear of the mounting plate, the output shaft of the stepper motor passes through the rear of the mounting plate, and synchronous pulleys are fixedly mounted on the output shaft of the stepper motor and the surface of the bottom end of the rotating cylinder respectively, and the two synchronous pulleys are connected by a synchronous belt transmission.

[0009] Preferably, a protective cover for accommodating the synchronous pulley and the synchronous belt is provided on the rear side of the mounting plate.

[0010] Preferably, the front end of the mounting cylinder is concave to form a hollow mounting hole, two pin holes are symmetrically provided on the side wall of the mounting hole, a positioning hole is provided at the rear end of the screwdriver bit, and the pin shaft passes through the pin hole and the positioning hole to install the screwdriver bit into the mounting cylinder, and an annular positioning groove is provided on the outer surface of the mounting cylinder at the annular surface where the pin hole is located, and an elastic ring is provided in the positioning groove to tighten the pin shaft.

[0011] Preferably, a bushing is fixedly connected to the rear end of the mounting post, an upper cover for pressing the connecting cylinder is provided on the top of the rotating cylinder, and the mounting post passes through the axis of the upper cover and extends upward.

[0012] Preferably, a locking nut located behind the bearing is provided on the surface of the rotating cylinder located in the inner cavity of the through hole.

[0013] Beneficial effects

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: a pre-tightening mechanism of the present invention tightens the bolt by setting an elastically retractable screwdriver bit, and pre-tightens the bolt by driving the stepper motor to rotate. The spring screwdriver bit cooperates with the motor to easily align with the bolt, so that the screwdriver bit and the bolt are in flexible contact, and the pre-tightening depth can be adjusted, and there will be no situation of tightening too deep or too shallow. At the same time, the pre-tightening mechanism is not easy to get stuck and damaged in unexpected situations, which is beneficial to improving the efficiency and consistency of the pre-tightening bolt process. Compared with electric tightening guns, it has a simple structure, a small size, and is easy to be arranged in components with relatively tight space layout. It relies on a mechanical mechanism to achieve depth control, with lower procurement and use costs, reduced human participation, automatic control, easy use, low operating costs, and can replace a variety of screwdriver bits with strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural diagram of the utility model;

[0016] Figure 2 This is a schematic structural diagram of the elastic mounting seat in the present invention;

[0017] Figure 3 This is a structural diagram of the screwdriver bit and the mounting barrel in the present invention;

[0018] Figure 4 This is a cross-sectional view of the elastic mounting seat of the utility model;

[0019] Figure 5 It is a structural diagram of the utility model;

[0020] Figure 6 This is a schematic diagram of an embodiment of the present invention.

[0021] In the figure: 1-mounting plate, 2-elastic mounting seat, 21-mounting sleeve, 22-bearing, 23-rotating cylinder, 24-mounting column, 25-bushing, 26-spring, 27-upper cover, 28-locking nut, 3-mounting cylinder, 4-bit, 5-stepping motor, 6-elastic ring, 7-pin shaft, 8-synchronous pulley, 9-synchronous belt. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] See also Figure 1-5 The utility model provides a technical solution: a pre-tightening mechanism, including a mounting plate 1, an elastic mounting seat 2 is provided on the mounting plate 1, a mounting tube 3 is fixedly connected to the elastic mounting seat 2, and a screwdriver bit 4 is detachably provided in the mounting tube 3.

[0024] The mounting tube 3 is installed on the elastic mounting seat 2, which can drive the bit 4 to extend and retract back and forth, thereby achieving flexible contact with the bolt and keeping it tight against the bolt. After the bolt is tightened to a certain depth, the bit 4 can be disengaged from the bolt to avoid overtightening.

[0025] The elastic mounting seat 2 includes a rotating cylinder 23 with an open front end, a mounting sleeve 21, a bearing 22 and a mounting column 24. The mounting sleeve 21 is fixedly connected to the mounting plate 1. The rotating cylinder 23 is rotatably arranged inside the mounting sleeve 21 through the bearing 22. The rear end of the mounting column 24 is telescopically arranged in the inner cavity of the rotating cylinder 23. The inner cavity of the rotating cylinder 23 is provided with a spring 26 for the expansion and contraction of the mounting column 24. The mounting cylinder 3 is fixedly connected to the end of the mounting column 24.

[0026] The mounting sleeve 21 is fixed on the mounting plate 1, and the bearing 22 is installed in the mounting sleeve 21 to limit the outer ring of the bearing 22. The locking nut 28 is installed on the rear side to prevent the bearing 22 from moving forward and backward. The rotating cylinder 23 is installed in the bearing 22 and is fixedly connected to the inner ring of the bearing 22, so that the movement of the rotating cylinder 23 can be limited and guided to ensure that it will not tilt or eccentric, and at the same time will not affect normal rotation.

[0027] The bottom end of the mounting post 24 is mounted in the rotating cylinder 23 and can move up and down relative to the rotating cylinder 23 but cannot rotate relative to the rotating cylinder 23 , so that the mounting post 24 can elastically expand and contract while maintaining synchronous rotation with the rotating cylinder 23 .

[0028] An annular flange structure is formed outward at the front end of the rotating cylinder 23, and the flange is pressed against the front end of the inner ring of the bearing 22, so that the rotating cylinder 23 can rotate normally. At the same time, it will be supported by the bearing 22, so that the rotating cylinder 23 itself will not move backward due to the backward squeezing of the screwdriver bit 4 at the front end.

[0029] A stepper motor 5 for driving a rotating cylinder 23 is provided on the mounting plate 1. The stepper motor 5 drives the rotating cylinder 23 to rotate, thereby driving the mounting column 24 to rotate, and then driving the mounting cylinder 3 to rotate, thereby driving the screwdriver bit 4 to rotate and tighten the bolt.

[0030] The stepper motor's holding torque is very low, only 0.5Nm. This means the motor can effectively tighten the bolt without damaging the components or the bolt due to overtightening. The pre-tightening depth of the bolt can also be adjusted by controlling the number of revolutions.

[0031] In this embodiment, when the device as a whole moves forward a certain distance, the bit 4 is in close contact with the bolt and is squeezed by the bolt for a certain distance, causing the mounting tube 3 and the mounting column 24 to move backward, the spring 26 will be compressed. At this time, the spring generates elastic force. When the stepper motor 5 drives the bit 4 to rotate in the opposite direction, the bit 4 will engage with the groove of the bolt head, and then the stepper motor 5 drives the bit 4 to rotate forward to tighten the bolt, while the position of the device as a whole remains unchanged. At this time, under the elastic force of the spring 26, the bit 4 will gradually extend forward and maintain contact with the bolt.

[0032] The pre-tightening depth can be controlled by adjusting the number of revolutions of the stepping motor 5 .

[0033] Furthermore, a through hole is opened on the mounting plate 1, and the rear end of the rotating cylinder 23 passes through the mounting sleeve 21, the bearing 22 and the through hole and extends to the rear of the mounting plate 1. The output shaft of the stepper motor 5 passes through the rear of the mounting plate 1. The output shaft of the stepper motor 5 and the surface of the bottom end of the rotating cylinder 23 are respectively fixedly mounted with synchronous pulleys 8, and the two synchronous pulleys 8 are connected by a synchronous belt 9.

[0034] Furthermore, a protective cover for accommodating the synchronous pulley 8 and the synchronous belt 9 is provided on the rear side of the mounting plate 1 .

[0035] In this embodiment, the protective cover can enclose the synchronous pulley 8 and the synchronous belt 9 to avoid installation accidents.

[0036] Furthermore, the front end of the mounting cylinder 3 is concave to form a hollow mounting hole, and two pin holes are symmetrically provided on the side wall of the mounting hole. A positioning hole is provided at the rear end of the screwdriver bit 4. The pin shaft 7 passes through the pin hole and the positioning hole to install the screwdriver bit 4 into the mounting cylinder 3. An annular positioning groove is provided on the outer surface of the mounting cylinder 3 at the annular surface where the pin hole is located, and an elastic ring 6 for tightening the pin shaft 7 is provided in the positioning groove.

[0037] In this embodiment, the pin 7 passes through the pin hole and the mounting hole, thereby fixing the rear end of the bit 4 to the mounting tube 3. At the same time, an elastic ring 6 is used to tighten the surface of the mounting tube 3 to limit the two ends of the pin 7 so that the pin 7 cannot fall out, ensuring the stable installation of the bit 4. When disassembling, first remove the elastic ring 6, then tilt the pin 7 out from one side, so that the bit 4 can be taken out.

[0038] Furthermore, a bushing 25 is fixedly connected to the rear end of the mounting post 24 , and an upper cover 27 for pressing the connecting cylinder 25 is provided on the top of the rotating cylinder 23 , and the mounting post 24 extends upward through the axis of the upper cover 27 .

[0039] In this embodiment, the connecting tube 25 is arranged in the rotating tube 23 and expands and contracts synchronously with the mounting column 24. At the same time, the front end of the spring 26 extends into the connecting tube 25 and presses against the rear end of the mounting column 24 to prevent the front end of the spring 26 from offsetting the rear end of the mounting column 24.

[0040] The upper cover 27 is inserted from the front end of the mounting column 24 and is tightened to the flange at the front end of the rotating cylinder 23 by bolts, etc., pressing the connecting cylinder 25 and limiting the maximum forward position of the connecting cylinder 25 and the mounting column 24 to prevent them from escaping from the rotating cylinder 23.

[0041] Furthermore, the surface of the rotating cylinder 23 located within the through-hole cavity is provided with a locking nut 28 located behind the bearing 22. The locking nut 28 is located on the rear end surface of the rotating cylinder 23 and is restrained by the rear end of the bearing 22, preventing forward movement. The locking nut 28 cooperates with the aforementioned flange to restrain the rotating cylinder 23 from forward and backward movement.

[0042] like Figure 6 As shown, another embodiment of the present invention is provided. Different from the above embodiment, the structures such as the mounting plate 1, the synchronous pulley 8 and the synchronous belt 9 are removed, and the stepper motor 5 is directly arranged at the rear end of the mounting sleeve 21 and connected to the rear end of the rotating cylinder 23 through a coupling to realize driving.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A pre-tightening mechanism, comprising a mounting plate (1), characterized in that: An elastic mounting seat (2) is provided on the mounting plate (1), a mounting tube (3) is fixedly connected to the elastic mounting seat (2), and a screwdriver bit (4) is detachably provided in the mounting tube (3); The elastic mounting seat (2) comprises a rotating cylinder (23) with an open front end, a mounting sleeve (21), a bearing (22) and a mounting post (24); the mounting sleeve (21) is fixedly connected to the mounting plate (1); the rotating cylinder (23) is rotatably arranged inside the mounting sleeve (21) via the bearing (22); the rear end of the mounting post (24) is arranged in the inner cavity of the rotating cylinder (23) so as to be telescopically movable; the inner cavity of the rotating cylinder (23) is provided with a spring (26) for the telescopic movement of the mounting post (24); and the mounting cylinder (3) is fixedly connected to the end of the mounting post (24); A stepping motor (5) for driving the rotating cylinder (23) to rotate is provided on the mounting plate (1).

2. A pre-tightening mechanism according to claim 1, characterized in that: A through hole is provided on the mounting plate (1); the rear end of the rotating cylinder (23) passes through the mounting sleeve (21), the bearing (22) and the through hole and extends to the rear of the mounting plate (1); the output shaft of the stepper motor (5) passes through the rear of the mounting plate (1); synchronous pulleys (8) are fixedly mounted on the output shaft of the stepper motor (5) and the surface of the bottom end of the rotating cylinder (23), respectively; the two synchronous pulleys (8) are connected by a synchronous belt (9).

3. A pre-tightening mechanism according to claim 2, characterized in that: A protective cover for accommodating the synchronous pulley (8) and the synchronous belt (9) is provided on the rear side of the mounting plate (1).

4. The pre-tightening mechanism according to claim 1, characterized in that: The front end of the mounting tube (3) is concave to form a hollow mounting hole, and two pin holes are symmetrically provided on the side wall of the mounting hole. A positioning hole is provided through the rear end of the screwdriver bit (4), and the screwdriver bit (4) is installed in the mounting tube (3) by passing the pin hole and the positioning hole. An annular positioning groove is provided on the outer surface of the mounting tube (3) at the annular surface where the pin hole is located, and an elastic ring (6) is provided in the positioning groove to tighten the pin shaft (7).

5. The pre-tightening mechanism according to claim 1, characterized in that: The rear end of the mounting column (24) is fixedly connected to a bushing (25), and the top of the rotating cylinder (23) is provided with an upper cover (27) for pressing the bushing (25), and the mounting column (24) passes through the axis of the upper cover (27) and extends upward.

6. The pre-tightening mechanism according to claim 2, characterized in that: A locking nut (28) located behind the bearing (22) is provided on the surface of the rotating cylinder (23) located in the inner cavity of the through hole.

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