TWI909375B - Return transmission of nailing rod for electric nail gun - Google Patents

Abstract

A return transmission of nailing rod for electric nail gun, comprising a pulley assembly and a return elastic component are arranged in a gun body frame. The pulley assembly includes an elastic towing rope, a movable pulley that guides the elastic towing rope and a guiding holder is provided for pivoting the movable pulley. When the nailing rod moves down along a striking stroke to strike the nail, the elastic towing rope can tow the movable pulley and drive the guiding holder to move an action stroke in a way that stores the elastic potential energy of the return elastic component. And then the return elastic component to drive the guiding holder according to a manner of release the elastic potential energy, so that the guiding holder can move back to its original position according to the action stroke, and the guiding holder tows the elastic towing rope by the movable pulley, so as to drive the nailing rod to move back to its original position according to the striking stroke, so as to reduce the load of the return elastic component.

Description

Electric nail gun's striker rod return transmission device

This invention relates to the transmission structure of an electric nail gun, and particularly to a return transmission device for the nail-driving rod of an electric nail gun.

Traditional electric nail guns mostly rely on a drive unit containing a motor, electromagnetic actuator, and flywheel to drive the nail-driving rod to perform a downward nail-driving action along a nail-driving stroke. They also rely on a coil spring or rubber band to transmit the nail-driving rod's upward repositioning action after the downward nail-driving stroke. The distance of the nail-driving stroke is fixed by the design. This invention specifically explores the upward repositioning technique of the nail-driving rod after performing a downward nail-driving action along a specific nail-driving stroke.

Similar techniques can be found in the disclosures of patents such as TWI340075, TWI349601, TW404604, and US10919136B2. Among them:

Patent TWI340075 teaches that a pair of helical compression springs arranged on both sides of the hammer rod along the hammer rod axis can store elastic potential energy by being compressed in conjunction with the hammer rod during the hammer rod's downward movement to strike the hammer. This elastic potential energy is then used to drive the hammer rod to quickly move upward to reset after the hammer rod has moved downward.

The difference between patent TWI349601 and the aforementioned patent TWI340075 is that patent TWI349601 places a pair of helical tension springs around a positioning roller (or fixed pulley), the purpose of which is to shorten the length of the pair of helical tension springs in the axial direction of the nail.

Patent TW404604 abandons the helical compression spring and helical tension spring used in the aforementioned patents TWI340075 and TWI349601 to drive the hammer rod upward for repositioning. Instead, it uses a pair of rubber bands to drive the hammer rod upward for repositioning.

Furthermore, US10919136B2 differs from the above-mentioned technology, and teaches the use of a torsion spring to drive the hammer rod to move upward and reset.

Therefore, it can be seen that the elastic elements used for resetting the hammer rod in existing electric nail guns are mostly made of metal springs (including helical tension springs, helical compression springs, and torsion springs) or rubber ribs. It is also known that the springs or rubber ribs used for resetting the hammer rod must be actuated (including stretched or compressed) by the hammer rod when it moves down to strike the nail, and then the elastic potential energy can be released by the actuation distance to drive the hammer rod to reset.

Therefore, the metal springs used in patents TWI340075, TWI349601, and US10919136B2 are prone to brittleness under prolonged high-impact operation. Since the operating distance of the spring to store elastic potential energy is equal to the striker stroke, the longer the striker stroke, the longer the operating distance (or stretching or compression distance) of the spring, and the more obvious the impact brittleness of the spring becomes.

However, although the rubber band taught in patent TW404604 can avoid the problem of springs being prone to impact brittleness, the elastic force that the rubber band can generate is far less than that of a spring. Moreover, when the operating distance of the rubber band to store elastic potential energy is "equal" to the driving stroke of the nail, it is still prone to elastic fatigue and reduced service life, especially after durable operation.

The inventor believes that, in order to pragmatically solve the technical problems existing in the prior art, an effort should be made to reduce the operating distance of the elastic element (defined in this invention as the reset elastic element) used for resetting the drive hammer rod when storing elastic potential energy. In other words, when the elastic potential energy stored in the reset elastic element is sufficient to drive the hammer rod to move upward and reset, an effort should be made to reduce the operating distance of the reset elastic element, that is, to make the operating distance greater than 0 and less than the hammer stroke (i.e., distance), so as to avoid the phenomenon of spring developing impact brittleness or rubber band experiencing elastic fatigue after durable use.

This invention utilizes a pulley block's interdependent transmission technology and a configuration means of using another elastic element within the pulley block as a traction rope (defined herein as an elastic traction rope) to assist the reset elastic element in providing elastic force during the reciprocating nail-hitting process of the nail-hitting rod. This shortens the operating distance of the reset elastic element and reduces the tensile force experienced by the elastic traction rope during nail-hitting, thereby improving the fatigue resistance and service life of the reset elastic element and the elastic traction rope.

Therefore, a preferred embodiment of the present invention provides a return transmission device for the striking rod of an electric nail gun, which is configured on a gun body support and includes: a motor drive unit, a striking rod, a pulley block, and at least one return spring member. Wherein:

The hammer rod slides along the hammer axis within the gun body bracket. Driven by the motor drive unit, the hammer rod moves downward along the hammer axis to strike the hammer.

The pulley assembly includes at least one movable pulley, a guide member, and at least one elastic traction rope. At least one of the movable pulleys is pivotally located within the guide member and rotates freely. The guide member carries at least one of the movable pulleys and is movable along the hammer pin axis. At least one of the elastic traction ropes has a head end and a tail end spaced apart by a specific length. The head end is fixed to the hammer pin rod, and the tail end is fixed to the gun body support. At least one movable pulley is positioned between the head end and the tail end to guide at least one of the elastic traction ropes.

At least one of the aforementioned reset spring members is disposed between the gun body support and the guide member for transmitting the movable guide member.

When the hammer rod moves downward to strike the nail according to the hammering stroke, it pulls at least one of the movable pulleys via at least one of the elastic traction ropes, thereby actuating the guide member and driving it to move an actuation stroke in a manner that stores the elastic potential energy of at least one of the reset elastic members. After the hammer rod moves downward to strike the nail, at least one of the reset elastic members transmits the guide member to move and reset according to the actuation stroke in a manner that releases the elastic potential energy. The guide member then pulls at least one of the elastic traction ropes via at least one of the movable pulleys, thereby actuating the hammer rod to move upward and reset according to the hammering stroke, so that the actuation stroke is greater than 0 and less than the hammering stroke.

In a further embodiment, the movable pulley in the pulley block is connected to the hammer rod and the gun body support in a dependent movement manner, so that the actuation stroke is greater than 0 and less than 1/2 of the hammer stroke. Furthermore, at least one of the elastic traction ropes is used to replace the cable used for the traditional traction pulley, and the elastic force provided by the at least one elastic traction rope is defined to be less than the elastic force provided by the at least one reset elastic member, so that during the nailing process, the at least one elastic traction rope can assist the reset elastic member in providing elastic force, thereby reducing the actuation stroke of the reset elastic member to less than 1/2 of the nailing stroke, in order to significantly improve the fatigue resistance and durability of the reset elastic member.

In a further embodiment, the pulley assembly also includes at least one fixed pulley positioned on the gun body support and freely rotating, with at least one of the fixed pulleys positioned between the head end and the guide member to guide at least one of the elastic traction ropes. At least one movable pulley is movable along the hammer-starting axis and positioned beside the hammer-starting rod, which has a striking portion. The at least one movable pulley is located along the hammer-starting axis between the at least one fixed pulley and the striking portion. The at least one fixed pulley is positioned along the hammer-starting axis on the gun body support above the hammer-starting rod.

In a further embodiment, at least one guide post is also disposed on the gun body support along the axis of the firing pin, and the guide member is slidably disposed on at least one of the guide posts to perform the movement of the actuation stroke. The at least one guide post is a pair of guide posts, each pair having a top end and a bottom end that can be fixedly connected to the gun body support. The at least one reset spring member is a pair of reset spring members, symmetrically disposed between the guide member and the bottom end, or symmetrically disposed between the top end and the guide member.

In a further embodiment, at least one of the elastic traction ropes can be made using a rubber band, and one of the rubber band, a helical compression spring, or a helical tension spring can be used as at least one of the reset elastic elements.

In summary, since prior art has not applied the interdependent transmission technology of pulley systems to nail guns, nor has it applied the use of elastic guide ropes as guide ropes for moving the pulleys, it can be understood from the above-described embodiments of the present invention that the present invention uses a fixed pulley and a movable pulley to guide an elastic guide rope, thereby enabling the movable pulley and the nail-driving rod to interdependently transmit power. This method can effectively reduce the operating distance of the return spring member storing elastic potential energy without affecting the predetermined nail-driving stroke. Therefore, this invention can eliminate or mitigate the problems of impact brittleness and elastic fatigue that easily arise in the reset elastic component, and can also eliminate the problem of the cable being easily damaged by the pulling force of the hammer rod. Furthermore, this invention can improve the fatigue resistance and service life of the reset elastic component and the elastic traction rope.

The implementation details and technical effects disclosed above will be presented in detail in the diagrams and implementation methods described below.

Please refer together to Figures 1 to 5, which together reveal the configuration details of the first preferred embodiment of the present invention, illustrating that the present invention is applied to the return transmission device of the hammer rod on an electric nail gun. The device is configured on a gun body support 10 of the electric nail gun, comprising: a motor drive unit 20, a hammer rod 30, a pulley block 40, and at least one reset spring member 50. Wherein:

As shown in Figures 1 and 2, the motor drive unit 20 includes an electromagnetic actuator 21 fixed to the top of the gun body bracket 10, and a swing arm 22 pivoted near the bottom of the gun body bracket 10. A power flywheel 23 is mounted on the swing arm 22. The power flywheel 23 is formed by a motor and a flywheel transmission connection, so that the power flywheel 23 has rotational kinetic energy. The motor can be an internal rotation motor or an external rotor motor. Motor; the transmission connection means that the flywheel is connected to the inner rotor motor by one side shaft, or by a belt loop wrapped around the flywheel and the inner rotor motor, or by connecting the flywheel shaft to the outer periphery of the outer rotor motor; in addition, the electromagnetic drive 21 is excited by an electromagnetic coil to generate a magnetic field to drive a push rod 21a to push the swing arm 22 to swing, and a compression spring 24 is provided between the swing arm 22 and the gun body bracket 10. With this configuration, when the electromagnetic actuator 21 is energized and drives the push rod 21a to push the swing arm 22 to swing, the swing arm 22 can drive the wheel surface of the power flywheel 23 to frictionally drive the hammer rod 30 to move downwards to strike the hammer (as shown in Figure 5 below). During this process, the compression spring 24 is compressed and stores an elastic thrust. When the electromagnetic actuator 21 is de-energized, it can release the swing arm 22. The swing arm 22 is pushed back to its original position by the elastic thrust of the compression spring 24, causing the wheel surface of the power flywheel 23 to disengage from the hammer rod 30.

Referring to Figure 3, at least one guide post is arranged on the gun body support 10 along the Z-axis of the hammer pin. In this embodiment, taking two pairs of first guide posts 11 as an example, it is explained that a pair of upper cushioning pads 11a and a pair of lower cushioning pads 11b are respectively arranged at their two ends. The hammer pin stroke L1 along the Z-axis is defined between the pair of upper cushioning pads 11a and the pair of lower cushioning pads 11b. A pair of slides 31 are respectively formed at the two ends of the top of the hammer pin rod 30, so that the pair of slides 31 can symmetrically slide on the pair of first guide posts 11 and sit on the pair of upper cushioning pads 11a and the pair of lower cushioning pads 11b. Between the lower buffer pads 11b, the hammer rod 30 slides along the hammer axis Z into the gun body bracket 10 by means of the sliding configuration of the slide block 31 and the first guide post 11, so that when the hammer rod 30 is driven by the motor drive unit 20, it moves down to strike the hammer along the hammer axis Z with the hammer stroke L1 (as shown in Figure 5, the direction of the hammer axis Z is the direction of hammer movement down), and the lower buffer pads 11b limit the hammer movement of the slide block 31 to the lower dead center position, and the upper buffer pads 11a limit the hammer movement of the slide block 31 to the upper dead center position.

As shown in Figures 1 and 2, the pulley assembly 40 includes a fixed pulley 41, a movable pulley 42, a guide member 43, and an elastic traction rope 44. The fixed pulley 41 and the movable pulley 42 are symmetrically arranged and are both freely rotating rope pulleys. The difference is that the fixed pulley 41 is positioned on the gun body bracket 10, and the movable pulley 42 is pivoted in the guide member 43, so that the movable pulley 42 moves along the hammer shaft Z and is positioned beside the hammer rod 30, while the fixed pulley 41 is positioned along the hammer shaft Z on the gun body bracket 10 above the hammer rod 30. In other words, as shown in Figures 2 and 5, the hammering rod 30 has a striking part 35. Whether before hammering (as shown in Figure 2) or after hammering (as shown in Figure 5), the movable pulley 42 can be positioned between the fixed pulley 41 and the striking part 35 along the hammering axis Z.

The guide member 43 is capable of supporting the movable pulley 42 and is movable along the hammer shaft in the Z direction. The way in which the guide member 43 is movable along the hammer shaft in the Z direction can be determined by at least one guide post symmetrically arranged along the hammer shaft in the Z direction on the gun body bracket 10. The at least one of the guide posts is marked as two pairs of second guide posts 12 in Figures 1, 2 and 4 to distinguish it from the first guide post 11 that provides the sliding assembly of the hammer rod 30. The guide member 43 is slidably arranged on the pair of second guide posts 12 and is movable along the hammer shaft in the Z direction, and performs an actuation stroke L2 (as shown in Figure 5, described in detail later). The elastic traction rope 44 is made of a hyperelastic material that has the ability to store potential energy through deformation. The hyperelastic material can be an elastomer or a rubber. In this embodiment, an elastic traction rope 44 is selected as an elastic stretchable and retractable rubber band (or a rubber band made of rubber components), and has a head end 44a and a tail end 44b spaced apart by a specific length; the head end 44a can be fixed to the hammer rod 30 by clamping or locking, and the tail end 44b can also be fixed to the top of the gun body bracket 10 by clamping or locking; the fixed pulley 41 is positioned between the head end 44a and the guide member 43 to guide the elastic traction rope 44, and the movable pulley 42 is positioned between the fixed pulley 41 and the tail end 44b to guide the elastic traction rope 44.

Please refer to Figure 4, which reveals that the guide member 43 can be made into a sliding block shape. A through hole 432 can be provided in the middle section of the guide member 43 so that the movable pulley 42 can be pivotally mounted in the through hole 432 and exposed to the outside. It can also freely rotate to allow the elastic traction rope 44 to be wound around, so that the guide member 43 and the elastic traction rope 44 can guide each other. In addition, at least one pair of left-right symmetrical hooks 431 can be extended at both ends of the guide member 43, and a pair of left-right symmetrical hooks 13 (marked in Figures 1 and 2) are formed near the bottom end of the gun body bracket 10 along the actuation stroke L2 shown in Figure 5.

In the embodiments shown in Figures 1 to 5, at least one of the return elastic members 50 is selected as two pairs of elastically stretchable and retractable rubber bands, which are symmetrically arranged between the hook 431 of the guide member 43 and the hook 13 near the bottom of the gun body bracket 10 (as shown in Figure 2). That is, the pair of return elastic members 50 can be symmetrically arranged between the gun body bracket 10 and the guide member 43 by means of the hook 431 and the hook 13 (as shown in Figures 1 and 2) to transmit the movement or sliding of the guide member 43, which is arranged on the pair of second pair of guide posts 12, to move the actuation stroke L2 (as shown in Figure 5, which will be described in detail later). In other words, as shown in Figure 2, the pair of second guide posts 12 each have a top end 12a and a bottom end 12b that can be fixed to the gun body bracket 10, and the pair of reset elastic members 50 are symmetrically arranged between the guide member 43 and the bottom end 12b.

Next, referring to Figures 2 and 5, Figure 2 shows the state of the hammer rod 30 before it moves down to strike the nail or after it moves up to reset according to the hammer stroke L1, and Figure 5 shows the state of the hammer rod 30 when it moves down to strike the nail according to the hammer stroke L1. When the hammer rod 30 moves down to strike the nail according to the hammer stroke L1 shown in Figure 2 to the state shown in Figure 5, the guide member 43 is driven by the elastic traction rope 44 to pull the movable pulley 42, thereby driving the guide member 43 to move the actuation stroke L2 shown in Figure 5 in a way that stores the elastic potential energy of the reset elastic member 50. After the hammer rod 30 strikes the nail downwards, as shown in Figure 5, the reset elastic member 50 transmits the guide member 43 to move and reset along the actuation stroke L2 in a manner that releases the elastic potential energy. The guide member 43 then pulls the elastic guide rope 44 via the movable pulley 42, which in turn drives the hammer rod 30 to move upwards and reset along the nailing stroke L1. The actuation stroke L2 is greater than 0 and less than the nailing stroke L1. Furthermore, due to the interdependent transmission configuration between the movable pulley 42 and the hammer rod 30, the actuation stroke L2 is only 1/2 of the nailing stroke L1. This design effectively reduces the distance that the reset spring member 50 is pulled by when the hammer rod 30 moves down to strike the hammer (i.e., shortens the stroke L2).

Since the elastic traction rope 44 and the return elastic member 50 in the embodiments shown in Figures 1-5 are both made of rubber tendons, and as mentioned above, rubber tendons are made of elastic rubber, which is a superelastic body or an elastic body (hereinafter, an elastic body is used as a representative example), the operating behavior of the elastic traction rope 44 and the return elastic member 50 both conform to the plastic deformation theory described in the strain life method. In this case, the amount of deformation (or displacement) generated by the elastic body after being subjected to force is particularly important. As shown in the following formula (1): ε = Equation (1) shows that the strain ( ε ) of an elastic body is defined as the ratio of the deformation (or displacement, ΔL ) of the elastic body to its original length ( L₀ ). This relationship reveals how displacement changes are transformed into strain values, thereby indicating the degree of deformation of the elastic body.

Furthermore, the simplified Coffin-Manson equation is used to describe the fatigue behavior of the rubber band, in order to consider the effect of plastic strain on fatigue life, as shown in the following equation (2): In equation (2), This indicates the magnitude of plastic strain in an elastic body. The fatigue strain coefficient of an elastic body. is the number of cycles required for an elastic body to reach fatigue failure (i.e., fatigue life), while b is the fatigue index of the plastic strain of the elastic body (a material constant).

Therefore, it can be seen that by reducing the travel L2 (i.e., displacement ΔL ) of the rubber band when the nail-driving rod 30 moves downward to strike the nail, the present invention will inevitably reduce the amplitude of plastic strain of the rubber band (or elastic body or return elastic element 50), thereby significantly improving the fatigue resistance and service life of the return elastic element 50 during the reciprocating nail-driving process, and also eliminating the problem of impact brittleness that traditional coil springs are prone to generate.

In addition, in the first embodiment described above, the elastic traction rope 44 can replace the steel cable used for the traditional traction pulley, so that the actuation stroke L2 is further less than 1/2 of the nailing stroke L1 (see the description of the third embodiment below), thereby further improving the fatigue resistance and service life of the reset elastic member 50.

Next, please refer to Figures 6 to 8 together to reveal the configuration details of the second embodiment of the present invention. The difference between the second embodiment and the first embodiment shown in Figures 1 to 5 is only that the second embodiment uses two pairs of helical springs (in the example, helical compression springs) as the reset elastic members 51, and the pair of reset elastic members 51 made of helical springs are symmetrically arranged between the top end 12a of the pair of second guide posts 12 and the top wall of the guide member 43, around the outer perimeter of the second guide post 12 (as shown in Figures 6 and 7). Otherwise, it is the same as the content disclosed in the first embodiment and produces the same interdependent transmission action, thereby reducing the actuation stroke L2 of the guide member 43. Furthermore, in the second embodiment, when the hammer rod 30 moves downward to strike the nail (as shown in Figure 8), the elastic traction rope 44 pulls the pulley 42 and the guide member 43 upward according to the actuation stroke L2, causing the pair of return elastic members 51 made of helical springs to be compressed. The guide member 43 is then driven to move downward to return to its original position according to the actuation stroke L2 (as shown in Figure 7) in a manner that first stores the elastic potential energy and then immediately releases it. During this process, the pair of return elastic members 51... The stroke L2 can also be greater than 0 and less than the nail-hitting stroke L1, or the stroke L2 can be only 1/2 of the nail-hitting stroke L1. Therefore, the reset spring member 51 can also effectively reduce the distance pulled by the nail-hitting rod 30 when it moves down to hit the nail (i.e., shorten the stroke L2), thereby reducing the possibility of the coil springs of the reset spring member 51, which is made of coil springs, impacting and colliding with each other, and thus greatly reducing the impact brittleness of the coil spring.

Furthermore, the reset spring 51 in the second embodiment described above is an example of a helical compression spring, and its configuration is explained accordingly. When the reset spring 51 is a pair of helical tension springs, the pair of helical tension springs can be arranged between the guide member 43 and the bottom end 12b of the pair of second guide posts 12, as guided by the reset spring 50 described in the first embodiment, to produce an equivalent effect. This should be interpreted as a technical application that can be easily changed by the present invention, and is described again.

Furthermore, in the second embodiment described above, the configuration of the elastic traction rope 44 also enables the actuation stroke L2 to be less than 1/2 of the nail stroke L1 (see the description of the third embodiment below), thereby further improving the fatigue resistance and service life of the reset elastic member 51.

Next, please refer to Figures 9 to 11 together to reveal the configuration details of the third embodiment of the present invention. The difference between it and the first and second embodiments mentioned above is that the fixed pulley 41 shown in Figures 1 to 8 is omitted, so that the pulley assembly 40 only needs to include the movable pulley 42, the guide member 43 and the elastic traction rope 44.

Specifically, Figure 9 shows that the guide member 43, which is made in the form of a slide block, is mounted on the second guide post 12 of the gun body bracket 10 and is configured to move along the Z-axis of the hammer pin. Figure 10 shows the movable pulley 42 pivoted on the guide member 43 and the elastic traction rope 44 guided by the movable pulley 42. The head end 44a of the elastic traction rope 44 is fixed to the hammer pin rod 30 and the tail end 44b is fixed to the gun body bracket 10. The pair of return spring members 52, made of helical springs, can be arranged between the bottom end of the gun body bracket 10 and the bottom of the guide member 43 by means of the guidance of the second guide post 12, so as to drive the guide member 43 to reciprocate along the Z-axis of the hammer pin. Figure 11 shows that when the hammer rod 30 moves downward to strike the nail, the hammer rod 30, via the elastic traction rope 44, pulls the pulley 42 and the guide member 43 downward by the stroke L2, thereby compressing the pair of return elastic members 52. This allows the pair of return elastic members 52 to transmit the guide member 43 upward according to the stroke L2 to return to the state shown in Figure 10 by releasing elastic force. During this process, the stroke L2 of the return elastic members 52 can also reach a large value. As a result of the action stroke L2 being 0 and less than the nail-hitting stroke L1, or being only 1/2 of the nail-hitting stroke L1, the reset spring member 52 can also effectively reduce the movement distance of the movable pulley 42 and guide member 43 pulled by the nail-hitting rod 30 when it moves down to hit the nail (i.e., shorten the action stroke L2). Otherwise, it is the same as the contents disclosed in the first and second embodiments above, and produces an equivalent effect.

In addition, taking the configuration of the third embodiment described above as an example, this invention will further illustrate that the elastic traction rope 44 can be made of rubber with an elasticity coefficient equal to or greater than that of the return elastic member 52, so that the elastic force generated by the elastic traction rope 44 is greater than or equal to that of the return elastic member 52, and the elastic traction rope 44 and The total elastic force generated by the reset elastic element 52 is much smaller than the force exerted by the flywheel 23 on the downward movement of the hammer rod 30. In this case, the present invention can, based on the aforementioned interdependent transmission technology and Hooke's law, and by means of the configuration of the elastic traction rope 44, make the actuation stroke L2 less than 1/2 of the hammer stroke L1.

In detail, please refer back to Figure 10. Before the nail is struck, the elastic force generated by the elastic traction rope 44 already contains a relatively small predetermined tension to pull the nail-striking rod 30. The predetermined tension of the elastic traction rope 44 is equal to the pressing force of the reset elastic member 52 when it is configured. At this time, the movable pulley 42 and the guide member 43 have not yet been moved by the elastic traction rope 44. Continuing in the process of the nail-striking rod 30 moving downwards as shown in Figures 9 and 10, the force of the power flywheel 23 driving the nail-striking rod 30 downwards will first absorb the... The predetermined tension of the elastic traction rope 44 and the pressing force of the reset elastic member 52, followed by the movement of the hammer nail as the hammer nail rod 30 moves downward, stretch the elastic traction rope 44. The elongation of the elastic traction rope 44 will reduce the compression of the reset elastic member 52 by the push of the pulley 42 and the guide member 43. Based on this, the actuation stroke L2 of the reset elastic member 52 can be less than 1/2 of the hammer nail stroke L1, and even further improve the fatigue resistance and service life of the reset elastic member 50.

In addition, as shown in Figure 11, when the hammer rod 30 completes its downward hammering action, the slide block 31 will strike the lower cushion 11b located at the bottom of the gun body support 10, causing the lower cushion 11b to be slightly compressed along the hammer axis Z. A pulling force is then transmitted to the elastic traction rope 44 through the slide block 31 and the hammer rod 30. At this time, the elastic traction rope 44 can absorb the pulling force with its own elasticity to avoid damage during durable operation.

Furthermore, based on the interdependent transmission configuration of the movable pulley 42 and the configuration of the elastic traction rope 44 to pull the hammer rod 30 with the predetermined tension, once the hammer rod 30 moves down to strike the nail, the force released by the reset elastic member 50 according to its own elastic potential energy must be more than twice the elastic force of the elastic traction rope 44, so as to ensure that the reset elastic member 50 can drive the hammer rod 30 to move up to reset.

Next, please refer to Figure 12, which reveals the configuration structure of the fourth embodiment of the invention. The difference between this fourth and third embodiments lies in that the guide member 43 has two pairs of movable pulleys 42 mounted on it, each guiding one of the elastic traction ropes 44. Apart from this, the structural configuration and nail-operating mechanism of the fourth embodiment are identical to those disclosed in the third embodiment.

It must be understood that, according to the fourth embodiment shown in Figure 12, the pair of movable pulleys 42 can guide the pair of elastic traction ropes 44. When the hammer rod 30 completes its downward hammering and causes the slide block 31 to strike the lower cushion 11b, the pulling force transmitted to the elastic traction rope 44 through the slide block 31 and the hammer rod 30 can be further dispersed. Therefore, compared with the third embodiment, the fourth embodiment can further enhance the fatigue resistance and service life of the elastic traction rope 44.

Furthermore, the third and fourth embodiments described above are based on the structural configuration of the fixed pulley 41 in the first and second embodiments, which is omitted. In contrast, the corresponding configuration of the fixed pulley 41 in the first and second embodiments in the third and fourth embodiments, corresponding to the number of movable pulleys 42 and elastic traction ropes 44, also falls within the scope of the simple transformation technology conceived by this invention.

Furthermore, as disclosed in the first to fourth embodiments above, the number of movable pulleys 42 and elastic traction ropes 44 can be singular or in pairs. The return elastic member 50 can be made of either rubber bands or helical springs (including helical compression springs and helical tension springs), all of which can effectively reduce the operating distance of the return elastic member to store elastic potential energy, thereby improving the fatigue resistance and service life of the return elastic member and elastic traction rope. Therefore, any simple substitutions that perform equivalent functions according to the content disclosed in the foregoing embodiments should be interpreted as falling within the technical scope covered by this invention and are described herein.

The above embodiments are merely illustrative of preferred embodiments of the present invention and should not be construed as limiting the scope of the patent application. Therefore, the present invention shall be governed by the claims as defined in the patent application.

10: Gun Body Support 11: First Guide Post 11a: Upper Cushion 11b: Lower Cushion 12: Second Guide Post 12a: Top End 12b: Bottom End 13: Hook Button 20: Motor Drive Unit 21: Electromagnetic Driver 21a: Push Rod 22: Swing Arm 23: Power Flywheel 24: Compression Spring 30: Striking Rod 31: Slide Block 35: Striking Part 40: Pulley Block 41: Fixed Pulley 42: Moving Pulley 43: Guide Component 431: Hook Lug 432: Through Hole 44: Elastic Traction Rope 44a: Head End 44b: Tail end 50, 51, 52: Reset spring mechanism L1: Impact pin stroke L2: Actuation stroke Z: Impact pin axial direction

Figure 1 is a perspective view of the first embodiment of the present invention. Figure 2 is a front view of Figure 1. Figure 3 is a cross-sectional view along section A-A in Figure 2. Figure 4 is a perspective view and enlarged view of the guide and movable pulley shown in Figures 1 and 2. Figure 5 is a schematic diagram of the action of driving the hammer rod downward to strike the hammer in the state shown in Figure 2. Figure 6 is a perspective view of the second embodiment of the present invention. Figure 7 is a front view of Figure 6. Figure 8 is a schematic diagram of the action of driving the hammer rod downward to strike the hammer in the state shown in Figure 7. Figure 9 is a perspective view of the third embodiment of the present invention. Figure 10 is a front cross-sectional view of Figure 9. Figure 11 is a cross-sectional view of the action of driving the hammer-action rod to move downwards and strike the hammer in the state shown in Figure 10. Figure 12 is a perspective view of the fourth embodiment of the present invention.

10: Gun Body Support 11: First Guide Post 12: Second Guide Post 13: Hook Button 20: Motor Drive Unit 21: Electromagnetic Driver 21a: Push Rod 22: Swing Arm 23: Power Flywheel 24: Compression Spring 30: Striking Rod Rod 31: Slide Block 40: Pulley Block 41: Fixed Pulley 42: Moving Pulley 43: Guide Component 44: Elastic Traction Rope 50: Returning Elastic Component Z: Striking Rod Axis

Claims (13)

A hammer rod return transmission device for an electric hammer gun is configured on a gun body support and includes: a motor drive unit; a hammer rod that slides along a hammer rod axis within the gun body support, the hammer rod being driven by the motor drive unit to move the hammer rod downwards along the hammer rod axis for a hammer stroke; A pulley assembly includes at least one movable pulley, a guide member, and at least one elastic traction rope; at least one of the movable pulleys is pivotally disposed within the guide member and rotates freely, the guide member also supports the at least one movable pulley and is movable along the hammer pin axis; the at least one elastic traction rope has a head end and a tail end spaced apart by a specific length, the head end is fixed to the hammer pin rod, the tail end is fixed to the gun body support, and the at least one movable pulley is positioned between the head end and the tail end to guide the at least one elastic traction rope; at least one return spring member is disposed between the gun body support and the guide member for transmitting the movable guide member; Specifically, when the hammer rod moves downwards to strike the nail according to the hammering stroke, at least one of the elastic guide ropes pulls at least one movable pulley, thereby actuating the guide member. This causes the guide member to move an actuation stroke by storing the elastic potential energy of at least one reset elastic member. After the hammer rod strikes the nail, at least one reset elastic member releases the elastic potential energy, thereby transmitting the guide member to move actuation stroke according to the actuation stroke. The guide moves and resets via a stroke, and the guide is pulled by at least one of the elastic guide ropes via at least one of the movable pulleys, thereby actuating the hammer rod to move upward and reset according to the hammer stroke, wherein the actuation stroke is greater than 0 and less than the hammer stroke, at least one of the movable pulleys is mounted on the guide in a pair, and at least one of the elastic guide ropes is guided by the pair of movable pulleys in a pair. The return drive of the hammer rod of the electric hammer as described in claim 1, wherein the actuation stroke is greater than 0 and equal to or less than 1/2 of the hammer stroke. The return drive device for the hammer rod of the electric nail gun as described in claim 1, wherein at least one of the elastic traction ropes is a rubber band, and at least one of the reset elastic members is one of a rubber band, a helical compression spring, and a helical tension spring. The return drive device for the hammer rod of the electric hammer as described in claim 1, wherein the pulley assembly further includes at least one fixed pulley positioned on the gun body support and rotating freely, and at least one of the fixed pulleys is located between the head end and the guide member and guides at least one of the elastic traction ropes. The return drive device for the hammer rod of the electric hammer as described in claim 4, wherein at least one of the movable pulleys is movable and disposed beside the hammer rod along the hammer rod axis, the hammer rod having a striking part, and the at least one of the movable pulleys is located between the at least one of the fixed pulleys and the striking part along the hammer rod axis. The return drive device for the hammer rod of the electric hammer as described in claim 1 or 5, wherein at least one of the fixed pulleys is positioned on the gun body support above the hammer rod along the hammer rod axis. The return drive device for the hammer rod of the electric hammer as described in claim 6, wherein at least one of the fixed pulleys is positioned in pairs on the gun body support and rotates freely, and at least one of the movable pulleys is mounted in pairs on the guide, and at least one of the elastic guide ropes is guided in pairs by the pairs of fixed pulleys and the pairs of movable pulleys. The return drive device for the hammer rod of the electric hammer as described in claim 1, wherein at least one guide post is further disposed on the gun body support along the hammer axis, and the guide member is slidably disposed on at least one of the guide posts to perform the movement of the actuation stroke. As described in claim 8, the return transmission device for the hammer rod of the electric hammer is wherein at least one of the guide posts is a pair of guide posts, each pair of guide posts having a top end and a bottom end that can be fixedly connected to the gun body support; and at least one of the return spring members is a pair of return spring members, the pair of return spring members being symmetrically arranged between the guide member and the bottom end. The return drive device for the hammer rod of the electric hammer as described in claim 8, wherein at least one of the guide posts is a pair of guide posts, each guide post having a top end and a bottom end that can be fixedly connected to the gun body support, and at least one of the return spring members is a pair of return spring members, each return spring member being symmetrically arranged between the top end and the guide member. The return drive of the hammer rod of the electric hammer as described in claim 9 or 10, wherein the pair of return springs is one of a pair of rubber bands, a pair of helical compression springs, or a pair of helical tension springs. The return drive of the hammer rod of the electric nail gun as described in claim 11, wherein the pair of elastic traction ropes is a pair of rubber bands. The return drive of the hammer rod of the electric hammer as described in claim 11, wherein the actuation stroke is greater than 0 and less than 1/2 of the hammer stroke.