Patent Description:
The present invention relates to a nail gun according to the preamble of claim <NUM>.

Nail guns in the market may be classified as mechanical nail guns and cylinder-type nail guns according to a principle manner. For a cylinder-type nail gun, gases in a cylinder push out a firing assembly so that a nailing action is performed. The process may be defined as one nailing cycle where the firing assembly moves from an initial position in the cylinder to a firing position and then moves from the firing position to the initial position. Generally, after a nail is driven out, a firing pin of the firing assembly rebounds for a short distance under the action of a rebound force, so a transmission tooth of the firing pin impacts a drive tooth of a drive wheel. As time passes, the drive tooth or the transmission tooth will be seriously abraded. As a result, the service life of the machine is affected.

Document <CIT> discloses a nail gun according to the preamble of claim <NUM>.

The present invention provides a nail gun according to claim <NUM>. The nail gun includes: a housing formed with an accommodating space; a cylinder connected to the housing and used for storing gases; a firing assembly at least partially disposed in the cylinder and capable of moving from an initial position to a firing position in the cylinder to drive a nail out; a power output assembly disposed in the accommodating space formed by the housing and used for outputting a driving force to drive the firing assembly to move in the cylinder; and a drive wheel connected to an output shaft of the power output assembly and used for driving, under the drive of the power output assembly, the firing assembly to move in the cylinder. The drive wheel has a first drive tooth and second drive teeth, where the radius of the addendum circle of the first drive tooth is less than the radius of the addendum circle of a second drive tooth, the first drive tooth is a drive tooth disposed at a start end of the drive wheel, and the first drive tooth meshes with the firing assembly when the drive wheel starts driving the firing assembly to reset.

The present application discloses a nail gun. The nail gun includes: a housing formed with an accommodating space; a cylinder connected to the housing and used for storing gases; a firing assembly at least partially disposed in the cylinder and capable of moving from an initial position to a firing position in the cylinder to drive a nail out; a power output assembly disposed in the accommodating space and used for outputting a driving force to drive the firing assembly to move in the cylinder; and a drive wheel connected to an output shaft of the power output assembly and used for driving, under the drive of the power output assembly, the firing assembly to move in the cylinder. The drive wheel has a first drive tooth and second drive teeth, where the ratio of the radius of the addendum circle of the first drive tooth to the radius of the addendum circle of the second drive tooth is higher than or equal to <NUM> and lower than <NUM>, the first drive tooth is a drive tooth disposed at a start end of the drive wheel, and the first drive tooth meshes with the firing assembly when the drive wheel starts driving the firing assembly to reset.

A nail gun <NUM> shown in <FIG> includes a housing <NUM>, a power output assembly <NUM>, a cylinder <NUM>, a magazine assembly <NUM>, a battery pack <NUM>, and a firing assembly <NUM>.

As shown in <FIG>, the power output assembly <NUM> includes an electric motor <NUM>, a gearbox <NUM>, a back stopping assembly <NUM>, an output shaft <NUM>, and a drive wheel <NUM>. The electric motor <NUM> can output power to the gearbox <NUM>. After the transmission of the gearbox <NUM>, the power continues being outputted to the output shaft <NUM>, and the drive wheel <NUM> is disposed on the output shaft <NUM>. For example, the electric motor <NUM>, the gearbox <NUM>, the back stopping assembly <NUM>, the output shaft <NUM>, and the drive wheel <NUM> are distributed along the direction of a first straight line <NUM>. A transmission mechanism is disposed in the gearbox <NUM>, and the back stopping assembly <NUM> is disposed in the gearbox <NUM> and is disposed at an end of the transmission mechanism or in the middle of the transmission mechanism. As an implementation, the back stopping assembly <NUM> allows the output shaft <NUM> to be capable of outputting a driving force only along a first rotation direction and limits the rotation of the output shaft <NUM> in a second rotation direction opposite to the first rotation direction.

As shown in <FIG> and <FIG>, the firing assembly <NUM> includes a firing pin <NUM>, a piston <NUM>, and a metal member <NUM>, where the firing pin <NUM> is fixed to the metal member <NUM>, and the piston <NUM> is sleeved on the outer side of the metal member <NUM>. A metal groove <NUM> is disposed on the metal member <NUM> and a rubber ring <NUM> is sleeved on the metal groove <NUM>. Transmission teeth 161a are formed on the firing pin <NUM>, and the transmission teeth 161a and the firing pin <NUM> can move along the direction of a second straight line <NUM> in the cylinder <NUM>. The drive wheel <NUM> can mate with the transmission teeth 161a to drive the firing assembly <NUM> to work against air pressure in the cylinder <NUM> so that the firing assembly <NUM> can move into a firing position.

As shown in <FIG> and <FIG>, the housing <NUM> includes a first accommodating space <NUM> formed and extending along the direction of the first straight line <NUM> and a second accommodating space <NUM> formed and extending along the direction of the second straight line <NUM>. The power output assembly <NUM> is disposed in the first accommodating space <NUM>, and the cylinder <NUM> is disposed in the second accommodating space <NUM>. The housing <NUM> is further formed with a handle <NUM> which can be held by a user. A power interface is connected to an end of the handle <NUM> and is configured to access a direct current power supply or an alternating current power supply. A main switch 113a is disposed on the handle <NUM>, and the user controls, through the main switch 113a, the nail gun <NUM> to start or stop. In this example, the power interface is connected to the battery pack <NUM>. The other end of the handle <NUM> is connected to the cylinder <NUM>, and the cylinder <NUM> extends along the direction of the second straight line <NUM>, where the first straight line <NUM> and the second straight line <NUM> are perpendicular to each other. The magazine assembly <NUM> is disposed in the direction of a third straight line <NUM> parallel to the first straight line <NUM>. As an optional example, the magazine assembly <NUM> is further provided with a window <NUM> that allows the user to observe remaining nails. The window <NUM> is configured to be one or more gaps on the magazine assembly <NUM>. On one hand, the window <NUM> may be used by the user to view the quantity of remaining nails, and on the other hand, the window <NUM> may be used by the user to perform simple maintenance on the magazine assembly <NUM> without detaching the magazine assembly <NUM>. The firing assembly <NUM> is disposed in the cylinder <NUM>, and gases in the cylinder <NUM> perform work so as to push the firing assembly <NUM> to move to drive out a nail. In this example, the cylinder <NUM> further includes an inflation nozzle used for inflating the gases into the cylinder <NUM> in advance. The power output assembly <NUM> drives the drive wheel <NUM> to rotate so that the firing assembly <NUM> is driven to compress the gases to move from an initial position to a firing position. In this case, the gases perform the work, and under the action of the gases inflated in advance, the firing assembly <NUM> is continuously pushed to have acceleration. Thus, the firing assembly <NUM> drives the nail out with relatively great kinetic energy, and after the nail is driven out, the firing assembly <NUM> quickly moves from the firing position to the initial position, thereby completing a nailing cycle.

It is to be understood that the firing assembly <NUM> may rebound upward for a short distance from a striking position due to a rebound force of a striking object when the firing assembly <NUM> drives the nail out. In the process where the firing assembly <NUM> rebounds, an impact between the firing pin <NUM> and the drive wheel <NUM> may be caused, so drive teeth of the drive wheel <NUM> and/or the transmission teeth on the firing pin <NUM> are abraded. To improve the preceding situation, the present application adjusts the structure of the drive wheel <NUM> and/or the structure of the firing pin <NUM>, so as to avoid the case where when the firing pin <NUM> rebounds, the firing pin <NUM> impacts the drive wheel <NUM>, causing the drive teeth and the transmission teeth to be abraded.

In an example, as shown in <FIG>, the drive wheel <NUM> is a gear structure. The drive wheel <NUM> is further formed with a connection hole 125a which can be connected to the output shaft <NUM>. For example, the connection hole 125a is a flat hole, and when the output shaft <NUM> is connected to the connection hole 125a, the drive wheel <NUM> can rotate synchronously with the output shaft <NUM>. Multiple drive teeth <NUM> are formed around the body of the drive wheel <NUM>. The drive teeth <NUM> include a first drive tooth 125b disposed at a start end and other drive teeth <NUM> except the first drive tooth 125b. In the present application, a drive tooth except the first drive tooth 125b on the drive teeth <NUM> is referred to as a second drive tooth. Here, when the drive wheel <NUM> starts driving the firing assembly <NUM> to reset, the drive tooth <NUM> which first comes into contact with the firing pin <NUM> in the firing assembly <NUM> is the first drive tooth 125b, and the drive teeth except the first drive tooth 125b are second drive teeth 125d. The first drive tooth 125b and the second drive teeth 125d are uniformly distributed in a first section 125e of the drive wheel <NUM>. A second section 125f of the drive wheel <NUM> is smooth and continuous, and no drive tooth <NUM> is distributed in the second section 125f. As shown in <FIG> and <FIG>, when the drive teeth <NUM> in the first section 125e mesh with the transmission teeth 161a on the firing pin <NUM>, the drive wheel <NUM> can drive the firing pin <NUM> to compress the gases in the cylinder <NUM> to perform the work. When the first drive tooth 125b in the first section 125e starts meshing with a transmission tooth 161a on the firing pin <NUM>, the drive wheel <NUM> starts driving the firing pin <NUM> to push the piston such that the gases in cylinder <NUM> are compressed to perform the work. When the second section 125f mates with the firing pin <NUM>, because the second section 125f is smooth and continuous, the firing pin <NUM> is quickly pushed out by the gases in the cylinder <NUM> without being blocked by the drive teeth <NUM>, thereby implementing nailing.

It is to be understood that the transmission teeth 161a are distributed on a side of the firing pin <NUM> and can mesh with the drive teeth <NUM> of the drive wheel <NUM> so that the firing pin <NUM> can drive, under the drive of the drive wheel <NUM>, the piston to compress the gases in the cylinder to perform the work.

In an example, the addendum circle C1 of the first drive tooth 125b and the addendum circle C2 of the second drive tooth 125d are shown in <FIG>. The radius R1 of the addendum circle of the first drive tooth 125b of the drive wheel <NUM> is less than the radius R2 of the addendum circle of the second drive tooth 125d, where R1 and R2 are radii represented by bold solid lines in <FIG>. In an implementation, the ratio of the radius R1 of the addendum circle of the first drive tooth 125b to the radius R2 of the addendum circle of the second drive tooth 125d is lower than <NUM>. In an example, the ratio of R1 to R2 is higher than or equal to <NUM> and lower than <NUM>. The length of the radius R1 of the addendum circle of the first drive tooth 125b is reduced so that an impact force of the transmission tooth 161a on the first drive tooth 125b is significantly reduced when the firing pin <NUM> moves upward due to the rebound force. Thus, the abrasion degree between the transmission tooth 161a and the first drive tooth 125b is reduced, and the case is avoided where the life of the whole machine is affected by the friction between the firing pin <NUM> and the drive wheel <NUM>.

The drive tooth <NUM> and the transmission tooth <NUM> can mesh with each other, and a certain meshing length may exist between the drive tooth <NUM> and the transmission tooth <NUM>. The meshing length refers to the length of the contact surface between the drive tooth <NUM> and the transmission tooth <NUM> along the extension line of the tooth. As shown in <FIG>, when the firing pin <NUM> moves upward due to the rebound force, the first drive tooth 125b and the transmission tooth 161a cannot mesh with each other or the meshing length between the two teeth is relatively small. In an example, as shown in <FIG>, when the second drive tooth 125d and the transmission tooth 161a mesh with each other, the meshing length is relatively large.

In an example, a certain first difference exists between the radius of the addendum circle of the first drive tooth 125b and the radius of the addendum circle of the second drive tooth 125d, and a certain meshing length exists between the drive tooth on the drive wheel <NUM> except the first drive tooth 125b and a transmission tooth on the firing pin <NUM> except a second transmission tooth <NUM>. In an example, the ratio of the preceding first difference to the preceding meshing length is higher than or equal to <NUM> and lower than or equal to <NUM>. For example, the ratio of the preceding first difference to the preceding meshing length is <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. In an example, as shown in <FIG>, according to the distance between the transmission tooth 161a and the piston <NUM>, the transmission teeth 161a of the firing pin <NUM> are sequentially defined as a first transmission tooth <NUM>, the second transmission tooth <NUM>, a third transmission tooth <NUM>, and the like. It is to be understood that in the process where the firing pin <NUM> moves from the firing position to the initial position, the first transmission tooth <NUM> first meshes with the first drive tooth 125b of the drive wheel <NUM>. That is to say, if the firing pin <NUM> drives the nail and then moves upward due to the rebound force, the second transmission tooth <NUM> first impacts the first drive tooth 125b. In an implementation, the distance between the first transmission tooth <NUM> and the second transmission tooth <NUM> may be increased. For example, assuming that the distance between the first transmission tooth <NUM> of the firing pin <NUM> and the second transmission tooth <NUM> of the firing pin <NUM> is S1 and the distance between the second transmission tooth <NUM> of the firing pin <NUM> and the third transmission tooth <NUM> of the firing pin <NUM> is S2, S1 is greater than S2. In an example, the distance between other adjacent transmission teeth 161a except the first transmission tooth <NUM> and the second transmission tooth <NUM> is S2. The distance between the first transmission tooth <NUM> and the second transmission tooth <NUM> is increased so that in the process where the firing pin <NUM> drives the nail and then rebounds, the rebound force is converted into the driving force driving the firing pin <NUM> to move and is consumed in the process where the firing ping <NUM> moves the distance S1. Thus, the impact force between the drive wheel <NUM> and the firing pin <NUM> is avoided or reduced. In an implementation, the ratio of S1 to S2 is lower than <NUM>. In an example, the ratio of S1 to S2 is higher than or equal to <NUM> and lower than <NUM>. In an example, the distance between the first transmission tooth <NUM> and the second transmission tooth <NUM> may be increased according to the magnitude of pressure in the cylinder <NUM>. For example, the higher the pressure in the cylinder <NUM>, the greater the distance S1 set between the first transmission tooth <NUM> and the second transmission tooth <NUM>. It is to be understood that in addition to the pressure in the cylinder <NUM>, S1 is further related to the tooth thickness of the transmission tooth of the firing pin <NUM> or the modulus of the gear.

In an example, the tooth height H3 of the second transmission tooth <NUM> of the firing pin <NUM> may be reduced, that is, the tooth height of the second transmission tooth <NUM> is less than the tooth height of the first transmission tooth <NUM> or the tooth height of the third transmission tooth <NUM>. Optionally, the second transmission tooth <NUM> is the transmission tooth with a minimum tooth height among all the transmission teeth 161a. In the process where the firing pin <NUM> drives the nail and then rebounds, the firing pin <NUM> is driven by the rebound force to move upward. Since the second transmission tooth <NUM> is relatively small, the first drive tooth 125b may impact or may not come into contact with the firing pin <NUM> in the process where the firing pin <NUM> moves upward. If the first drive tooth 125b is not in contact with the second transmission tooth <NUM> in the process where the firing pin <NUM> moves upward, the impact force between the first drive tooth 125b and the third transmission tooth <NUM> is significantly reduced after the firing pin is driven by the rebound force to move the distance S3. The distance S3 is the distance between the first transmission tooth <NUM> and the third transmission tooth <NUM>, that is, S3 = S1 + S2. If the first drive tooth 125b and the second transmission tooth <NUM> with a relatively low tooth height impact each other for the first time in the process where the firing pin <NUM> moves upward, the impact force does not cause relatively great abrasion on the drive wheel <NUM>, but the rebound force is counteracted significantly. Thus, the case is avoided where the relatively great second impact force is caused between the first drive tooth 125b and the third transmission tooth <NUM> and the service lives of the drive wheel <NUM> and the firing pin <NUM> are affected.

That is to say, the height of the second transmission tooth <NUM> is reduced so that the distance which the firing pin <NUM> can be driven by the rebound force to move is increased in a different form. The distance is the distance between the first transmission tooth <NUM> and the third transmission tooth <NUM>. Thus, the impact force between the first drive tooth 125b of the drive wheel <NUM> and the first transmission tooth <NUM> of the firing pin <NUM> is avoided or reduced.

In an implementation, the ratio of the tooth height H3 of the second transmission tooth <NUM> to the radius R1 of the addendum circle of the first drive tooth 125b is lower than <NUM>. It is to be understood that the tooth height H4 of the second transmission tooth <NUM> may be set according to the radius R1 of the addendum circle of the first drive tooth 125b as long as it needs to be ensured that the firing pin <NUM> can apply a relatively small impact force between the second transmission tooth <NUM> and the first drive tooth 125b. That is to say, when the firing pin <NUM> rebounds upward, a certain impact force may also exist between the second transmission tooth <NUM> and the first drive tooth 125b as long as the impact force is small enough so that no relatively large abrasion is caused by the impact force between the transmission tooth and/or the drive tooth.

In an example, a second difference exists between the tooth height of the first transmission tooth <NUM> and the tooth height of the second transmission tooth <NUM> or the tooth height of the third transmission tooth <NUM>, and the ratio of the difference to the preceding meshing length is lower than <NUM>. For example, the ratio of the second difference to the preceding meshing length is <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like.

In an example, a controller of the electric motor may control the rotational speed of the electric motor to vary. For example, in the process where the drive wheel <NUM> drives the firing pin <NUM> to move from the initial position to the firing position, the controller controls the electric motor to reduce the rotational speed, or when the drive wheel <NUM> drives the firing pin <NUM> to move from the initial position to the firing position and start rising from the firing position to the initial position, the rotational speed of the electric motor is reduced. In general, the rotational speed of the electric motor may be reduced in the process in which the firing pin <NUM> is about to move upward or has moved upward so that the force with which the firing pin <NUM> rebounds up and down can be reduced.

In an example, the impact force between the drive wheel <NUM> and the firing pin <NUM> may be reduced in one manner or through the combination of multiple manners.

It is to be understood that if the firing assembly <NUM> is heavier, more work performed by the compressed gases in the cylinder <NUM> is used for working against the inertia of the firing assembly <NUM>, so a striking force is significantly reduced. That is to say, the heavier the firing assembly <NUM>, that is, the piston <NUM> and the firing pin <NUM>, the worse the nailing effect of the nail gun.

Therefore, in the present application, the weight of the firing assembly <NUM> may be reduced so that the nailing effect of the nail gun is improved. Optionally, the firing needle <NUM> may be made of a relatively light material with a relatively hard texture, or the piston may be made of a lighter material with better anti-impact performance.

For example, the middle portion of the metal member <NUM> shown in <FIG> and <FIG> may be hollowed out so that the weight of the metal member <NUM> is reduced, thereby reducing the weight of the firing assembly <NUM>.

In another example, referring to <FIG>, some structures in this example are the same as those in the preceding example and the same reference numerals are also used, and different reference numerals are used for different parts for differentiation.

In this example, the nail gun <NUM> may further include a first back stopping member <NUM> and a second back stopping member <NUM>. The drive wheel <NUM> and the second back stopping member <NUM> are disposed on the output shaft <NUM>. As shown in <FIG>, the transmission teeth 161a are formed on one side of the firing pin <NUM>, and a back stopping tooth 161b is formed on the other side of the firing pin <NUM>. The piston and the firing pin <NUM> can move along the direction of the second straight line <NUM> in the cylinder <NUM>. The drive wheel <NUM> can mate with the transmission teeth 161a to drive the firing assembly <NUM> to work against the air pressure in the cylinder <NUM> so that the firing assembly <NUM> can move into the firing position. The back stopping tooth 162b can cooperate with the first back stopping member <NUM> to lock the firing pin <NUM> in the initial position or near the initial position. For example, the electric motor <NUM>, the gearbox <NUM>, the output shaft <NUM>, the second back stopping member <NUM>, and the drive wheel <NUM> are distributed along the direction of the first straight line <NUM>.

At the end of a nailing cycle, the firing assembly <NUM> is located in the initial position or near the initial position, and the first back stopping member <NUM> may lock the firing assembly <NUM> in the initial position or near the initial position. The movement of the firing assembly <NUM> from the initial position to the firing position can be blocked when no nail is driven. In the present application, the second back stopping member <NUM> may cooperate with the first back stopping member <NUM> to complete locking or unlocking the firing assembly <NUM>. The implementation process is described below.

As shown in <FIG> and <FIG>, the first back stopping member <NUM> includes a locking portion <NUM>, a driven member <NUM>, and an elastic member <NUM>. When the firing assembly <NUM> is located in the initial position or near the initial position, the locking portion <NUM> locks the firing assembly <NUM>. It may be understood that the second drive tooth 125d of the drive wheel <NUM> locks the firing pin <NUM> to prevent the firing pin <NUM> from falling down when the firing assembly <NUM> is located in the initial position or near the initial position while the first back stopping member <NUM> mainly prevents the firing pin <NUM> from sliding down when the locking effect of the drive wheel <NUM> fails. Therefore, the first back stopping member <NUM> may be considered to assist the drive wheel <NUM> in locking the firing pin <NUM>. Further, when the firing assembly <NUM> is in a locked state and the drive wheel <NUM> continues rotating, the second section 125f of the drive wheel <NUM> is not in contact with the firing pin <NUM>. In addition, since the driven member <NUM> is connected to the locking portion <NUM>, the driven member <NUM> can be pushed by a protruding portion <NUM> of the second back stopping member <NUM>. Thus, the locking portion <NUM> is driven to move away from the firing pin <NUM> to cooperate with the drive wheel <NUM> to unlock the firing assembly <NUM> so that the firing assembly <NUM> can shoot the nail from the initial position. Further, the elastic member <NUM> is connected to the locking portion <NUM>. When the locking portion <NUM> is pushed by the driven member <NUM> to unlock the firing assembly <NUM>, the elastic member <NUM> is in a compressed state. Thus, when a pushing force of the driven member <NUM> on the locking portion <NUM> disappears, the elastic portion <NUM> is released from the compressed state so that the locking portion <NUM> may be pushed to be in contact with the firing pin <NUM> again.

In an example, the locking portion <NUM> is an oddly-shaped structure which is integrally formed shown in <FIG>, where the locking portion <NUM> has a protruding boss 171a which is in direct contact with the firing assembly <NUM>, a cylindrical connection portion 171b, and a connection portion 171c. The driven member <NUM> and the elastic member <NUM> are fixed on two sides of an end of the connection portion 171c separately. The direction of the pushing force applied to the locking portion <NUM> by the driven member <NUM> is opposite to the direction of the elastic force applied to the locking portion <NUM> by the elastic member <NUM>. In an example, the driven member <NUM> may be a cylindrical inserted pin, and the elastic member <NUM> may be a component with elasticity, such as a spring or a spring contact.

In an example, a contact 172a with a smooth and continuous surface may be disposed on the end of the driven member <NUM> facing away from the connection portion 171c. The contact 172a may be a metal ball and may be connected to the driven member <NUM> through a port 172b.

It is to be understood that during the rotation of the output shaft <NUM>, when the second section 125f mates with the firing pin <NUM>, the protruding portion <NUM> of the second back stopping member <NUM> abuts against the driven member <NUM> and the driven member <NUM> can be pushed by the protruding portion <NUM> to move so that the locking portion <NUM> is pushed away and is not in contact with the firing pin <NUM> and can cooperate with the drive wheel <NUM> to unlock the firing assembly <NUM>. In addition, since the second section 124f is smooth and continuous, in the case where the drive tooth <NUM> or the locking portion <NUM> does not block the firing pin <NUM>, the firing pin <NUM> is quickly pushed out by the gases in the cylinder <NUM>, thereby implementing the nailing effect. When the drive teeth <NUM> in the first section 125e mesh with the transmission teeth 161a on the firing pin <NUM>, a non-protruding portion <NUM> is no longer in contact with the driven member <NUM>, and the elastic member <NUM> is released from the compressed state and can push the locking portion <NUM> to abut against the firing pin <NUM> again. Thus, after the firing pin <NUM> is driven by the drive teeth <NUM> in the first section 125e of the drive wheel <NUM> to move upward to the initial position, the locking portion <NUM> is in contact with the firing pin <NUM> and is located below the back stopping tooth 161b. In the process where the firing pin <NUM> moves upward from the firing position, the driving force of the drive wheel <NUM> to drive the transmission teeth 161a to rotate is greater than the elastic force applied to the locking portion <NUM> by the elastic member <NUM>. Therefore, even if the locking portion <NUM> applies a certain resistance to the back stopping tooth 161b on the firing pin <NUM>, the drive wheel <NUM> may drive the firing pin <NUM> to move upward.

In an implementation, in the process where the firing pin <NUM> moves upward from the firing position, to minimize the resistance of the locking portion <NUM> to the back stopping tooth 161b, the back stopping tooth 161b may be designed as a ratchet. A tooth tip of the ratchet is downward, which can ensure that in the process where the firing pin <NUM> moves upward, the firing pin <NUM> can easily slide over the ratchet when the locking portion <NUM> is above the back stopping tooth 161b and the firing pin <NUM> can be locked to be incapable of sliding down when the locking portion <NUM> is below the back stopping tooth 161b.

In the nail gun disclosed by the examples of the present application, the size or distance of the tooth on the drive wheel or the tooth on the firing pin is properly adjusted so that the impact between the drive force and the firing pin can be effectively avoided when the firing pin drives the nail and then rebounds, thereby ensuring the service life of the whole nail gun.

Claim 1:
A nail gun (<NUM>), comprising:
a housing (<NUM>) formed with an accommodating space (<NUM>);
a cylinder (<NUM>) connected to the housing and used for storing gases;
a firing assembly (<NUM>) at least partially disposed in the cylinder and capable of moving from an initial position to a firing position in the cylinder to drive a nail out;
a power output assembly (<NUM>) disposed in the accommodating space and used for outputting a driving force to drive the firing assembly to move in the cylinder; and
a drive wheel (<NUM>) connected to an output shaft of the power output assembly and used for driving, under the drive of the power output assembly, the firing assembly to move in the cylinder;
wherein the drive wheel has a first drive tooth (125b) and second drive teeth (125d),
characterized in that a
radius of an addendum circle of the first drive tooth is less than a radius of an addendum circle of a second drive tooth, the first drive tooth is a drive tooth disposed at a start end of the drive wheel, and the first drive tooth meshes with the firing assembly when the drive wheel starts driving the firing assembly to reset.