Fastening tool

Abstract

The application provides a fastening tool, which comprises a shell, a motor, an impact assembly, a first cylinder, a second cylinder and a second piston, the second cylinder is sleeved outside the first cylinder, the impact assembly comprises a first piston and a hitting part connected with the first piston, the first cylinder is formed with a first chamber, the second cylinder is formed with a second chamber, a valve assembly is arranged between the first chamber and the second chamber, the valve assembly has an open position allowing the first chamber to communicate with the second chamber and a closed position blocking the first chamber from communicating with the second chamber, a plurality of through holes and a first sealing element outside the plurality of through holes are arranged on the valve assembly, so that the gas in the first chamber can enter the second chamber when vacuumizing, and a plurality of air inlet holes are arranged on the side, away from the valve assembly, of the second cylinder.

Description

Technical Field

[0001] This utility model relates to the field of power tool technology, specifically to a fastening tool. Background Technology

[0002] A nail gun is a fastening tool used to quickly drive nails into a workpiece. Whether the nail can be driven into the workpiece completely is often closely related to the power used during nailing, the type of nail, and the material of the workpiece. When the parameters are not matched, situations such as the nail not being fully driven into the workpiece (nailing out) or the nail bending (nailing collapse) will occur, affecting the quality of nailing.

[0003] This section provides background information related to this application, which is not necessarily prior art. Utility Model Content

[0004] This application also provides a fastening tool, including:

[0005] case;

[0006] The motor is housed within the casing;

[0007] An impact assembly, the impact assembly including a first piston and a striking component connected to the first piston;

[0008] A first cylinder has a first chamber, and a first piston is disposed in the first chamber and is operable to reciprocate between two extreme positions, a first position and a second position. When the first piston approaches the second position, the striking component strikes the fastener.

[0009] The second cylinder is fitted outside the first cylinder and forms a second chamber that can communicate with the first chamber;

[0010] The second piston is disposed in the second chamber and is driven by the motor to reciprocate between two extreme positions, the third position and the fourth position, within the second chamber.

[0011] A valve assembly is disposed between the first chamber and the second chamber. The valve assembly has an open position that allows communication between the first chamber and the second chamber and a closed position that blocks communication between the first chamber and the second chamber. The second piston operably acts on the valve assembly to move the valve assembly from the closed position to the open position. The valve assembly is provided with a plurality of through holes and a first sealing element located outside the plurality of through holes. The position of the second piston near the valve assembly is defined as the fourth position. When the second piston moves from the fourth position to the third position, the gas in the first cylinder enters the second cylinder through the through holes. The side of the second cylinder away from the valve assembly is provided with a plurality of air inlets.

[0012] In one possible implementation, the second piston reciprocates between two extreme positions, a third position and a fourth position, within the second chamber, forming a second volume V2 of the second chamber. The ratio of the second volume V2 to the total cross-sectional area of ​​the plurality of through holes is greater than 2200 mm and less than 3600 mm.

[0013] In one possible implementation, the second piston contacts the valve assembly before reaching the fourth position, causing the valve assembly to move from the closed position to the open position.

[0014] In one possible implementation, the valve assembly is provided with a plurality of second protrusions extending radially or axially along the valve assembly. When the second piston moves from the third position to the fourth position, the second piston contacts the second protrusions, causing the valve assembly to move from the closed position to the open position.

[0015] In one possible implementation, the first cylinder and the second cylinder are connected by a tail cover, and the second piston is provided with a plurality of first protrusions that extend toward the tail cover.

[0016] In one possible implementation, the valve assembly is provided with a plurality of second protrusions extending radially along the valve assembly. When the second piston moves from the third position to the fourth position, the first protrusion contacts the second protrusion, causing the valve assembly to move from the closed position to the open position.

[0017] In one possible implementation, the valve assembly has a first side near the first piston and a second side opposite to the first side, the second side abutting against a spring and a cushioning pad, the spring causing the valve assembly to move from an open position to a closed position.

[0018] In one possible implementation, the first cylinder is provided with a plurality of exhaust holes. When the first piston moves to the second position, the gas in the first cylinder is discharged outward from the exhaust holes, and a second seal is provided on the outside of the exhaust holes.

[0019] In one possible implementation, the first cylinder is provided with an annular groove, and the distance between the exhaust port and the two sides of the second seal is different along the axial direction of the first cylinder.

[0020] In one possible implementation, the second seal has the same inner diameter and different outer diameters, with the exhaust port closer to the side with the smaller outer diameter along the axial direction of the first cylinder.

[0021] In one possible implementation, along the axial direction of the first cylinder, the distance between the exhaust port and the side closer to the second seal is less than 5 mm.

[0022] In one possible implementation, the first cylinder is provided with an annular groove, the exhaust port is provided on the annular groove, and a second seal is provided on the annular groove, with at least a portion of the second seal being higher than the annular groove.

[0023] The advantages of this application are: the first cylinder is set inside the second cylinder, and the gas in the first cylinder and the second cylinder are connected or disconnected through the valve assembly. A vacuum channel is provided in the valve assembly, so that when the second piston moves away from the valve assembly, other gases can enter the second cylinder through several through holes on the valve assembly, so that the first piston can complete the reset. After the second piston reaches a certain position, air can be directly introduced through the air inlet of the second cylinder. The structure is simple, does not increase the weight of the impact assembly, and makes the reset of the first piston stable.

[0024] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0026] Figure 1 A perspective view of a nail gun according to one embodiment of this application;

[0027] Figure 2 This is a cross-sectional view of a fastening tool according to one embodiment of this application;

[0028] Figure 3 This is a schematic diagram showing the second piston in a second position according to one embodiment of this application;

[0029] Figure 4 This is a schematic diagram of a nail-driving motion state of an impact component according to one embodiment of this application;

[0030] Figure 5 This is a schematic diagram showing the first piston in the fourth position according to one embodiment of this application;

[0031] Figure 6 This is a schematic diagram of a reset motion state of an impact assembly according to one embodiment of this application;

[0032] Figure 7 This is a schematic diagram showing the valve assembly after it has been removed.

[0033] Figure 8Another angle diagram showing the second cylinder hidden;

[0034] Figure 9 for Figure 5 A close-up view of valve assembly F;

[0035] Figure 10 for Figure 4 Enlarged view of a portion of the second seal at point G;

[0036] Figure 11 This is a three-dimensional view of the second seal.

[0037] Explanation of reference numerals in the attached figures:

[0038] 100-Fastening tool; 110-Housing housing; 111-Energy storage housing; 112-Tail cover; 113-Head cover; 114-Drive housing; 115-Grip housing; 116-Battery pack mating part; 120-Nose assembly; 130-Nail magazine; 140-Safety trigger lever; 150-Trigger; 151-Motor; 152-Crank-connecting rod mechanism; 153-Controller; 1530-Magnet; 1531-Sensor; 154-Second piston; 1541-First protrusion; 155-Second cylinder; 1551-Air inlet; 1 56-Impact assembly; 1560-First piston; 1562-Strike component; 1565-Buffer block; 157-First cylinder; 1571-Exhaust port; 1572-Second seal; 1573-Annular groove; 1574-First part; 1575-Second part; 158-Tail cap; 159-Valve assembly; 1591-Spring; 1592-First seal; 1593-Second protrusion; 1594-Buffer pad; 1595-Spring pressure plate; 1596-First side; 1597-Second side; 1598-Through hole. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the implementation methods and features in the implementation methods of this application can be combined with each other.

[0040] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0042] Some embodiments of this application provide a fastening tool 100, specifically a nail gun, used to generate an impact force on a nail, thereby forcing the nail into the workpiece. For example... Figure 1-2 As shown, the fastening tool 100 includes: a housing 110, a motor 151, an impact assembly 156, a first cylinder 157, a second cylinder 155, and a second piston 154. The motor 151 is disposed within the housing 110, and the impact assembly 156 includes a first piston 1560 and a striking component 1562 connected to the first piston 1560.

[0043] In some embodiments, the fastening tool 100 further includes a nozzle assembly 120, a safety trigger lever 140, and a trigger 150. After pressing the safety trigger lever 140 and pulling the trigger 150, the striking component 1562 strikes the fastener, which is supplied by the nail magazine 130 and ejected from the channel of the nozzle assembly 120. When the fastening tool 100 is held, the striking component 1562 moving in direction A to strike the fastener is defined as forward, moving in direction B away from the nozzle assembly 120 is defined as rearward, the direction along the extension direction generally parallel to the nail magazine 130, the direction closer to the nozzle assembly 120 is defined as upward, and the direction away from the nozzle assembly 120 is defined as downward. Furthermore, from the perspective of the operator holding the fastening tool 100, the left and right directions (vertical and forward / backward, up / down) are defined.

[0044] In some embodiments, the housing 110 includes an energy storage housing 111, a tail cover 112, a head cover 113, a drive housing 114, and a grip housing 115. The energy storage housing 111 extends in a front-rear direction, the head cover 113 is located in front of the energy storage housing 111, the drive housing 114 is substantially perpendicular to the energy storage housing 111, connects to the head cover 113 and extends in a vertical direction, and the grip housing 115 extends downward from the energy storage housing 111, is angled relative to the drive housing 114, and gradually moves away from the drive housing 114 in the downward direction, so that the drive housing 114 and the grip housing 115 are aligned. There is sufficient space between the housings 115 for gripping. The battery pack mating part 116 is located below the gripping housing 115 and connects the gripping housing 115 and the drive housing 114. The battery pack mating part 116 is used to connect the battery pack. The controller 153 is located in the housing space above the battery pack mating part 116. The tail cover 112 is located behind the energy storage housing 111 and is used to block the space at the rear of the energy storage housing 111. The blocking here only blocks the energy storage mechanism inside the energy storage housing 111, rather than sealing it. Gas can still enter the energy storage housing 111 through the tail cover 112.

[0045] The fastening tool 100 is powered by a rechargeable battery pack, such as a battery pack (not shown in the figure). The battery pack, in conjunction with a corresponding power circuit, powers the fastener driver 100. The fastening tool 100 can also be powered by other power sources, such as an AC power cord connected to mains power, or other connecting cables that can be connected to a power supply device. Mains power or other power sources, in conjunction with corresponding rectification, filtering, and voltage regulation circuits, power the corresponding components of the fastening tool 100.

[0046] In some embodiments, a first cylinder 157 and a second cylinder 155 are located within an energy storage housing 111. The first cylinder 157 has a first chamber, and a first piston 1560 is disposed within the first chamber. The second cylinder 155 is sleeved outside the first cylinder 157 and arranged parallel to it. The second cylinder 155 has a second chamber that communicates with the first chamber. A second piston 154 is disposed within the second chamber and can be driven by a motor 151 to reciprocate within the second chamber. Specifically, after the motor 151 is energized, it drives a crank-connecting rod mechanism 152 to reciprocate via a reduction mechanism. The crank-connecting rod mechanism 152 is connected to the second piston 154, driving the second piston 154 to reciprocate within the second chamber of the second cylinder 155. The second chamber is the space remaining after the first cylinder 157 is removed from the second cylinder 155.

[0047] In some embodiments, the first cylinder 157 has a first chamber, and the first piston 1560 is disposed in the first chamber and is operable to reciprocate between two extreme positions, a first position and a second position. When there is not enough gas acting on the first piston 1560, the first piston 1560 remains in the first position. When there is enough gas acting on the first piston 1560, the first piston 1560 moves from the first position to the second position. When the first piston 1560 approaches the second position, the striking member 1562 strikes the fastener.

[0048] In some embodiments, the second cylinder 155 is sleeved outside the first cylinder 157 and is arranged parallel to the first cylinder 157. The second cylinder 155 is formed with a second chamber that can communicate with the first chamber. The second piston 154 is disposed in the second chamber and can be driven by the motor 151 to reciprocate between two extreme positions, the third position and the fourth position, in the second chamber.

[0049] As can be seen, in one nailing cycle, the second piston 154 reciprocates between the two extreme positions of the third and fourth positions in the second chamber, and the first piston 1560 reciprocates between the two extreme positions of the first and second positions in the first chamber. As the second piston 154 moves from the third position to the fourth position, it generates high-pressure gas, which pushes the first piston 1560 from the first position to the second position, thus realizing nailing. As the second piston 154 moves from the fourth position to the third position, it generates negative pressure, which drives the first piston 1560 from the second position back to the first position, thus completing the reset of the first piston 1560, which completes one nailing cycle.

[0050] In some embodiments, a valve assembly 159 is disposed between the first chamber and the second chamber. The valve assembly 159 has an open position that allows communication between the first chamber and the second chamber and a closed position that blocks communication between the first chamber and the second chamber. The second piston 154 is operable to act on the valve assembly 159 to move the valve assembly 159 from the closed position to the open position. The position of the second piston 154 near the valve assembly 159 is defined as the fourth position. Specifically, the motor 151 drives the crank-connecting rod mechanism 152 to reciprocate through the reduction mechanism. The crank-connecting rod mechanism 152 is connected to the second piston 154 and drives the second piston 154 to reciprocate between the two extreme positions of the third position and the fourth position in the second chamber. When the second piston 154 moves from the third position to the fourth position, it contacts the valve assembly 159, causing the valve assembly 159 to move from the closed position to the open position.

[0051] By blocking the connection between the first chamber and the second chamber through the valve assembly 159, the impact assembly 156 is prevented from being driven when the air pressure is insufficient. That is, the gas acts on the first piston 1560 only when the second chamber has sufficient pressure, so that the impact assembly 156 can instantly obtain sufficient nail-driving force to hit the fastener. In this way, there is no need to set an additional mechanical holding and locking mechanism for the first piston 1560 or the striking part 1562, or to set magnets or the like to hold the first piston 1560. This reduces the overall weight of the impact assembly 156, and with fewer parts, the assembly is simpler and the cost is reduced.

[0052] In some embodiments, the valve assembly 159 is provided with a plurality of through holes 1598 and a first seal 1592 located outside the plurality of through holes 1598. When the second piston 154 moves from the fourth position to the third position, the gas in the first cylinder 157 enters the second cylinder 155 through the through holes 1598, so that the first piston 1560 completes the reset.

[0053] By directly providing a through hole 1598 on the valve assembly 159, when the second piston 154 is drawing a vacuum, gas can directly enter the second cylinder 155 from the first cylinder 157 through the through hole 1598. This avoids the need to open an additional hole in the first cylinder 157 to provide a vacuum channel, and avoids the risk of lengthening the first cylinder 157 and reducing its strength. In addition, by providing the through hole 1598 on the valve assembly 159, the weight of the valve assembly 159 is reduced. The combination of the through hole 1598 and the first seal 1592 can throttle the volume of the vacuum path, resulting in a better negative pressure effect and enabling the first piston 1560 to complete the reset in time.

[0054] In some embodiments, the second cylinder 155 is provided with a plurality of air inlets 1551 on the side away from the valve assembly 159. When the second piston 154 reaches the third position under the drive of the crank connecting rod, the second piston 154 passes through the air inlets 1551. At this time, external gas can enter the second chamber through the air inlets 1551, so that the second chamber is restored from negative pressure to atmospheric pressure. When the second piston 154 moves from the third position to the fourth position under the drive of the crank connecting rod, the second piston 154 will pass through the air inlets 1551, so that the second chamber is in a sealed state. As the second piston 154 moves to the fourth position, the gas in the second chamber is compressed. When the second piston 154 contacts the valve assembly 159, it opens the channel between the first chamber and the second chamber. The high-pressure gas will directly act on the first piston 1560, driving the impact assembly 156 to complete the nailing operation.

[0055] The second cylinder 155 has several air inlets 1551 on the side away from the valve assembly 159, allowing external air to naturally enter the second chamber when the second piston 154 is in the uncompressed position. As the second piston 154 moves from the uncompressed position to the maximum compression position, after passing the air inlets 1551, the second chamber forms a sealed cavity, eliminating the need for an additional sealing device. This design is simple and cost-effective. Furthermore, during the return process of the first piston 1560 after the second piston 154 has compressed and driven the nail, the area connecting the first and second chambers is reliably sealed, ensuring accurate repositioning of the first piston 1560. This prevents the first piston 1560 from failing to return to its original position due to unreliable sealing caused by other abnormal factors, thus ensuring normal nail driving.

[0056] Optionally, the second piston 154 is provided with either a magnet 1530 or a sensor 1531. The magnet 1530 or sensor 1531 moves synchronously with the movement of the second piston 154, while the other magnet 1530 or sensor 1531 is stationary relative to the housing 110. The sensor 1531 can detect the magnet 1530 and transmit the detection signal to the controller 153. By checking the signal, the position of the second piston 154 is identified, thereby the controller 153 controls the operation of the motor 151, for example, by braking the motor 151 or by allowing it to run continuously without braking.

[0057] In some embodiments, the first cylinder 157 and the second cylinder 155 are connected via a tail cap 158. Figures 2-6 A schematic diagram showing the sequential action of the first piston 1560 and the second piston 154. Figure 2 The second piston 154 is located in the third position, furthest from the tail cover 158, while the first piston 1560 is located in the first position, closest to the tail cover 158. As the crank-connecting rod mechanism 152 moves, the second piston 154 moves towards the tail cover 158, reaching... Figure 3 As shown in the fourth position near the tail cover 158, during this process, the second piston 154 contacts the valve assembly 159, opens the valve assembly 159, and opens the passage between the second chamber and the first chamber, so that the gas between the second chamber and the first chamber is connected. At this time, the gas compressed by the second piston 154 in the second cylinder 155 instantly enters the first cylinder 157, pushing the first piston 1560 to start moving away from the tail cover 158. The fourth position is defined as the position closest to the tail cover 158 after the second piston 154 pushes open the valve assembly 159.

[0058] In some embodiments, the second piston 154 reciprocates between two extreme positions, a third position and a fourth position, within the second chamber, forming a second volume V2 of the second chamber. The ratio of the second volume V2 to the total cross-sectional area of ​​the plurality of through holes 1598 is greater than 2200 mm² and less than 3600 mm², for example, ratios of 2524 mm², 2636 mm², 2839 mm², 3421 mm², etc. Here, the second volume V2 is the volume change of the second cylinder 155 caused by the movement of the second piston 154. This volume change is the volume change of the second chamber after subtracting the space occupied by the first cylinder 157. Specifically, one side of the second piston 154 is connected to the outside, and the other side of the second piston 154 forms a sealed space with the tail cap 158. The difference between the sealed space formed by the second piston 154 in the third position and the sealed space formed in the fourth position is the second volume V2. When the ratio of the second volume V2 to the total cross-sectional area of ​​the plurality of through holes 1598 is greater than 2200 mm² and less than 3600 mm², the first chamber... For gas to enter the second chamber within a predetermined time, meaning the second volume V2 must match the total cross-sectional area of ​​the through hole 1598, a suitable passage must be provided for gas from the first chamber to enter the second chamber. If the ratio is too small (i.e., the first volume is small while the cross-sectional area of ​​the through hole 1598 is large), insufficient energy storage will occur, failing to provide enough driving force to completely penetrate the fastener into the workpiece. If the ratio is too large (i.e., the first volume is large while the cross-sectional area of ​​the through hole 1598 is insufficient), the second piston 154 may have already reached the third position, passing the air inlet 1551, while the first piston 1560 has not yet reached the first position. Assuming the through hole sizes are consistent, the total cross-sectional area of ​​the through hole 1598 is the cross-sectional area of ​​the smallest point of a single through hole multiplied by the number of through holes. If the through hole sizes are inconsistent, the total cross-sectional area of ​​the through hole 1598 is the sum of the cross-sectional areas of the smallest points of each through hole.

[0059] In some embodiments, the first cylinder 157 and the second cylinder 155 are connected via a tail cap 158, such as Figures 7-8 As shown, the second piston 154 is provided with a plurality of first protrusions 1541, which extend toward the tail cap 158. In this way, the second piston 154 directly contacts the valve assembly 159 through the first protrusions 1541 to open the valve assembly 159.

[0060] In some embodiments, the valve assembly 159 is provided with a plurality of second protrusions 1593 extending radially along the valve assembly 159. When the second piston 154 moves from the third position to the fourth position, the first protrusion 154 contacts the second protrusions 1593, causing the valve assembly 159 to move from the closed position to the open position. The second protrusions 1593 extend directly radially from the valve assembly 159, thus the second protrusions 1593 can be formed together with the valve assembly 159, eliminating the need for separate components on the valve assembly for contacting the first protrusion 1541 of the second piston 154.

[0061] In some embodiments, there are a plurality of first protrusions 1541, for example, four, and a plurality of second protrusions 1593, the same number as the number of first protrusions. The first protrusions 1541 are evenly spaced along the second piston 154, while the second protrusions 1593 are evenly spaced along the valve assembly 159. This makes the force uniform when the first protrusions 1541 and the second protrusions 1593 come into contact, and the movement of the valve assembly 159 from the closed position to the open position is more stable.

[0062] In some embodiments, the second piston 154 may not have a first protrusion, and the second piston 154 may directly push the valve assembly 159 to open. Optionally, the second protrusion extends directly from the axial direction of the valve assembly 159, and the second piston 154 pushes the second protrusion to open the valve assembly 159.

[0063] In some embodiments, such as Figure 9 As shown, valve assembly 159 has a first side 1596 near the first piston 1560 and a second side 1597 opposite to the first side 1596. The second side 1597 abuts against the spring 1591 and the buffer pad 1594. When valve assembly 159 is in the open position, after the second piston 154 moves away from valve assembly 159, the spring 1594 causes valve assembly 159 to move from the open position to the closed position. Because high-pressure gas will directly act on valve assembly 159 at the moment of opening during axial movement of the valve assembly, valve assembly 159 opens at a relatively high speed. The buffer pad 1591 can reduce the vibration and impact caused by the movement of valve assembly 159 and prevent premature failure of components.

[0064] In some embodiments, the spring pressure plate 1595 is fixedly disposed at the rear end of the tail cover 158 to support the spring 1591 and the buffer pad 1594. The spring pressure plate 1595 is made of metal and its thickness can be reduced to meet mechanical strength requirements, thereby shortening the machine length.

[0065] In some embodiments, such as Figure 10 As shown, the first cylinder 157 is provided with several exhaust ports 1571. When the first piston 1560 moves to the second position, the gas in the first cylinder 157 is discharged outward from the exhaust ports 1571. A second seal 1572 is provided on the outside of the exhaust ports 1571 to seal the space of the first chamber when there is no high-pressure gas in the first chamber, so that the first piston 1572 can return to the first position after nailing is completed. As the second piston 154 continues to push the valve assembly 159 to move, the first piston 1560 moves to a position close to the exhaust ports 1571 and reaches... Figure 5The second position shown is after passing the exhaust port 1571. The second position is defined as the position when the first piston 1560 just contacts the buffer block 1565. Under normal circumstances, due to the action of high pressure gas, the first piston 1560 will continue to compress the buffer block 1565 after contacting the buffer block 1565 and continue to move forward a distance. When the first piston 1560 passes the exhaust port 1571, the high-pressure gas in the first cylinder 157 pushes open the second seal 1572 and is discharged outward from the exhaust port 1571. Subsequently, the crank-connecting rod mechanism 152 pulls the second piston 154 to move away from the tail cover 158. Under the action of the spring 1591, the valve assembly 159 returns to the state of closing the passage between the second chamber and the first chamber. A negative pressure is formed between the second piston 154 and the tail cover 158. Due to the pressure difference between the first cylinder 157 and the second cylinder 155, the gas in the first cylinder 157 flows into the second cylinder 155 through the through hole 1598 on the valve assembly 159, pushing open the first seal 1592 on the valve assembly 159. Figure 6 As shown, the first piston 1560 is pulled to move closer to the tail cap 158, thus completing the reset of the first piston 1560.

[0066] In some embodiments, along the axial direction of the first cylinder 157, the distances between the exhaust port 1571 and the two sides of the second seal 1572 are different. That is, the exhaust port 1571 is offset to one side of the second seal 1572, and the distance C4 between the exhaust port 1571 and one side of the second seal 1572 is different from the distance C5 between the exhaust port 1571 and the other side of the second seal 1572. This distance is the axial distance from the center of the exhaust port 1571 to one side of the second seal 1572. Generally speaking, the high-pressure gas of the first cylinder 157 will be discharged from the side of the exhaust port 1571 closer to the second seal 1572. Setting the exhaust port 1571 offset from one side of the second seal 1572 makes it easy for the high-pressure gas to be discharged from the same side of the second seal 1572. If it is not offset, the high-pressure gas may not be able to be discharged.

[0067] In some embodiments, such as Figure 11 As shown, the second seal 1572 has the same inner diameter and different outer diameters. The second part 1575 of the second seal 1572 has the same inner diameter and different outer diameters as the first part 1574. The outer diameter of the second part 1575 is larger than that of the first part. For example, the periphery of the second seal 1572 is stepped or conical. Along the axial direction of the first cylinder 157, the exhaust port 1571 is closer to the side with the smaller outer diameter. In this way, high-pressure gas can be more easily discharged through the side with the smaller outer diameter.

[0068] In some embodiments, along the axial direction of the first cylinder 157, the distance C4 between the exhaust port 1571 and the side closer to the second seal 1572 is less than 5 mm, so that high-pressure gas can be more easily discharged from the side closer to the second seal 1572.

[0069] In some embodiments, the first cylinder 157 is provided with an annular groove 1573 and an exhaust port 1571 is provided on the annular groove 1573 so that after nailing is completed, the high-pressure gas in the first chamber is discharged outward through the exhaust port 1571.

[0070] In some embodiments, a second seal 1572 is provided on the annular groove 1573 to facilitate the installation of the second seal 1572 and to prevent the second seal 1572 from shifting after the high-pressure gas pushes open the second seal 1572 and is discharged.

[0071] In some embodiments, at least a portion of the second seal 1572 is higher than the annular groove 1573. This allows high-pressure gas to escape from the first chamber after the first piston 1560 passes the vent hole 1571, pushing open the second seal 1572. Because at least a portion of the second seal 1572 is higher than the annular groove 1573, the second seal 1572 will not deviate from the annular groove 1573 due to high-pressure gas, thus preventing the sealing of the first chamber from being affected. Once the second seal 1572 is in the annular groove 1573, the first chamber will remain connected to the atmosphere through the vent hole 1571 during vacuum reset of the first piston 1560, preventing the first piston 1560 from being reset and affecting the normal nailing cycle, i.e., preventing the nailing operation from continuing.

[0072] In summary, by sealing and opening the gas communication channel between the first and second chambers through the valve assembly 159, no additional components are needed on the impact assembly 156, reducing the weight of the impact assembly 156. Furthermore, the vacuum gas channel is located on the valve assembly 159, thus avoiding the need for an additional channel on the first cylinder 157. Additionally, an air inlet 1551 is provided at the end of the second cylinder away from the valve assembly 159, facilitating the entry of external gas into the second chamber. The structure is simple while providing good sealing performance. The reset of the first piston 1560 is not affected by sealing or other factors, resulting in smooth nailing cycle. The fastening tool is compact, lightweight, portable, and comfortable to operate.

[0073] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. A fastening tool characterized by comprising: include: case; The motor is housed within the casing; An impact assembly, the impact assembly including a first piston and a striking component connected to the first piston; A first cylinder has a first chamber, and a first piston is disposed in the first chamber and is operable to reciprocate between two extreme positions, a first position and a second position. When the first piston approaches the second position, the striking component strikes the fastener. The second cylinder is fitted outside the first cylinder and forms a second chamber that can communicate with the first chamber; The second piston is disposed in the second chamber and is driven by the motor to reciprocate between two extreme positions, the third position and the fourth position, within the second chamber. A valve assembly is disposed between the first chamber and the second chamber. The valve assembly has an open position that allows communication between the first chamber and the second chamber and a closed position that blocks communication between the first chamber and the second chamber. The second piston operably acts on the valve assembly to move the valve assembly from the closed position to the open position. The valve assembly is provided with a plurality of through holes and a first seal located outside the plurality of through holes. The position of the second piston near the valve assembly is defined as the fourth position. When the second piston moves from the fourth position to the third position, the gas in the first cylinder enters the second cylinder through the through holes. The side of the second cylinder away from the valve assembly is provided with a plurality of air inlets.

2. The fastening tool of claim 1, wherein The second piston reciprocates between two extreme positions, the third and the fourth, within the second chamber, forming a second volume V2 of the second chamber. The ratio of the second volume V2 to the total cross-sectional area of ​​the plurality of through holes is greater than 2200 mm and less than 3600 mm.

3. The fastening tool of claim 1, wherein Before the second piston reaches the fourth position, it contacts the valve assembly, causing the valve assembly to move from the closed position to the open position.

4. The fastening tool according to claim 3, characterized in that, The valve assembly is provided with a plurality of second protrusions, which extend radially or axially along the valve assembly. When the second piston moves from the third position to the fourth position, the second piston contacts the second protrusions, causing the valve assembly to move from the closed position to the open position.

5. The fastening tool according to claim 1, characterized in that, The valve assembly has a first side near the first piston and a second side opposite to the first side, the second side abutting against a spring and a buffer pad, the spring causing the valve assembly to move from an open position to a closed position.

6. The fastening tool according to claim 1, characterized in that, The first cylinder is provided with a plurality of exhaust holes. When the first piston moves to the second position, the gas in the first cylinder is discharged outward from the exhaust holes. A second seal is provided on the outside of the exhaust holes.

7. The fastening tool according to claim 6, characterized in that, Along the axial direction of the first cylinder, the distance between the exhaust port and the two sides of the second seal is different.

8. The fastening tool according to claim 6, characterized in that, The second seal has the same inner diameter and different outer diameters, and along the axial direction of the first cylinder, the exhaust port is closer to the side with the smaller outer diameter.

9. The fastening tool according to claim 6, characterized in that, Along the axial direction of the first cylinder, the distance between the exhaust port and the side closer to the second seal is less than 5 mm.

10. The fastening tool according to claim 6, characterized in that, The first cylinder is provided with an annular groove, the exhaust port is provided on the annular groove, and a second seal is provided on the annular groove, at least a portion of the second seal being higher than the annular groove.

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