JPH0675829B2 - Power nailer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a power nailing machine. In particular, the present invention is
A power nailer in which a nail is driven by a piston operated by fluid pressure.

[Prior art]

Generally, a fluid pressure type power nailing machine has a fluid cylinder and a piston that operates in the fluid cylinder, and a blade for nail driving is attached to the piston. The blade is guided by a nose fixed to the cylinder under fluid pressure and descends to drive a nail pre-filled in the nose toward an object. The nose is provided with a nose piece that is pressed against the surface on which the nail is driven. The tip of the blade must be
It is arranged so as to project below the lower surface of the nose piece at the driving position.

[Problems to be solved by the invention]

In the conventional power nailing machine described above, since the tip of the nail driving blade projects below the lower surface of the nose piece at the driving position, depending on the nature of the surface to be nailed, problems such as surface cracking may occur. May occur. For example, when nailing a material that is prone to cracking, such as a flat plate slate roofing material, the tip of the blade hits the roofing material during driving, and a localized concentrated pressure is applied to the roofing material. The use of power nailers on this type of roofing material was difficult as it could crack. Especially in the case of roofing materials, the lower edge of the upper roofing material is arranged so as to overlap the upper edge of the lower roofing material,
A part of the roof material on the upper side is in a state of being lifted from the foundation structure, and a nail will be driven into this lifted portion, which makes the condition more fragile.

An object of the present invention is to provide a power nailing machine capable of performing nailing by a power nailing machine without causing cracks or the like in a material that is easily cracked or a material that is subjected to a condition that is easily cracked. To do.

[Means for solving problems]

In order to solve the above-mentioned problems, the power nailing machine according to the present invention is provided with means for distributing the driving pressure to other portions at the end of the nailing stroke without concentrating the pressure on the blade tip. That is, in the present invention, the nose is not fixed to the cylinder but is coupled to the sub piston provided in the cylinder, and the driving piston hits the sub piston at the end of the driving stroke and a part of the driving force is applied from the sub piston. Give to the nose. A nose piece that is pressed against the surface to be nailed is provided at the tip of the nose,
Part of the force applied from the driving piston is transmitted to the surface to be nailed through the nose piece.

That is, the power nailing machine according to the present invention has a fluid cylinder and a driving piston axially slidably arranged in the fluid cylinder, and a nailing blade is attached to the driving piston. The blade is of a type adapted to be guided by a nose provided at the tip of the cylinder.In the fluid cylinder, an auxiliary piston that is slidably movable in the axial direction of the fluid cylinder is provided below the driving piston. The auxiliary piston is arranged so as to hit the driving piston near the bottom dead center of the driving piston, and the nose is attached to the auxiliary piston.
The nose piece is provided with a nose piece that is pressed against a surface to be nailed.

Further, another feature of the present invention is that the cushioning material is arranged on either or both of the side facing the driving piston and the opposite side of the auxiliary piston. Still another feature is that, when the cushioning material is arranged on both sides of the sub piston, the cushioning material on the side facing the driving piston has a property of being harder than the cushioning material on the other side. Still another feature of the present invention is that the tip surface of the nose piece, which is applied to the nailed surface, is located substantially flush with the bottom dead center position of the blade tip during driving. In order to facilitate the achievement of this positional relationship, it is desirable that the nose be adjustable in length.

[Work]

According to the above-described configuration of the present invention, in the nail striking stroke, the blade first hits the head of the nail in the nose to drive the nail toward the target object to drive it. Then, at the end of the driving stroke, the driving piston hits the sub piston, and a part of the impact force is applied to the sub piston and the nose connected thereto. For this reason, the impact force of the driving piston does not concentrate only on the part where the blade tip hits, but is also distributed to the part where the nose piece hits, preventing the problem of cracking the parts nailed by the impact of the blade tip. it can. If the cushioning material is disposed on one side or both sides of the sub piston, the impact force can be dispersed more smoothly. Also, if the tip surface of the nose piece, which is applied to the surface to be nailed, is located substantially on the same plane as the bottom dead center position of the blade tip at the time of driving, the impact force of driving can be dispersed more effectively. Will be seen. That is, if the tip surface of the nose piece is below the bottom dead center, the blade does not reach the surface where the tip is nailed, and effective driving is not performed.
Conversely, if the tip surface of the nose piece is above the bottom dead center of the blade tip when driving, the blade tip will hit the nailed surface before the impact piston hits the auxiliary piston, and the impact force The dispersion is delayed by that amount. The positional relationship between the position of the blade tip and the tip surface of the nose piece can be easily achieved by making the length of the nose adjustable.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. First of all
Referring to the drawing, the power nailing machine 1 of the present embodiment has a cylinder housing 2, and a cylinder bore 3 is formed in the cylinder housing 2. A driving piston 4 for driving a nail is arranged in the cylinder bore 3 so as to be slidable in the axial direction. A handle portion 5 is provided on the cylinder housing 2, and a trigger 6 is provided near the base of the handle portion 5.
Is provided. A trigger valve 7 operated by the trigger 6 is provided, and the trigger valve 7 is operated by the operation of the trigger 6 to open and close the passage of compressed air and drive the driving piston 4 downward. A nail driving blade 8 is fixed to the driving piston 4, and the blade 8 strikes the head of the nail to drive the object. When the driving piston 4 reaches the bottom dead center, the air passage in the cylinder housing 2 is switched, the driving piston 4 is driven upward, and returns to the original position. Since the structure for switching the compressed air passage for driving the driving piston 4 as described above is well known in the field of nail driving machines, detailed description thereof will be omitted.

The lower end of the cylinder bore 3 is an enlarged portion 3a having a large diameter, and the sub piston 9 is arranged in the enlarged portion 3a. A hollow cylinder-shaped nose upper portion 10 is integrally formed with the sub piston 9. A hollow cylindrical nose lower part 11 is joined to the lower end of the nose upper part 10 to form a nose 12. The blade 8 fixed to the driving piston 4 is axially slidably inserted into a nose 12 constituted by the nose upper portion 10 and the nose lower portion 11. A cushioning material 13 is arranged on the upper surface of the sub piston 9, and a cushioning material 14 is arranged on the lower surface thereof.

The nose upper part 10 and the nose lower part 11 that compose the nose 12 are
They are connected to each other by a screw mechanism that allows the length of the nose to be adjusted. This screw mechanism has a screw ring 16 fixed to the upper part 10 of the nose by a fixing pin 15, and this screw ring 16
The male screw is formed on the. Upper end 11 of lower nose 11
A male screw is also formed on a, and the adjusting nut 17 engages with this male screw. The adjusting nut 17 has a threaded ring 16 at its upper end surface.
It is arranged so as to abut the lower end surface of the. A stop nut 18 is arranged outside the adjusting nut 17. The lock nut 18 has an internal thread that engages with the external thread of the threaded ring 16 at the top, and an inward flange 18a is formed at the lower end. Therefore, when the lock nut 18 is screw-engaged with the screw ring 16, the lower end flange 18a of the lock nut 18 is
Engages the lower end surface of the adjusting nut 17 and presses the upper end surface of the adjusting nut 17 against the lower end surface of the screw ring 16. At this time,
With the lock nut 18 threadedly engaged with the ring 16,
A gap is formed between the lower end surface of 16 and the lower end flange 18a of the lock nut 18 so that the adjusting nut 17 can freely rotate. With this structure, the axial position of the adjusting nut 17 with respect to the lower nose 11 can be adjusted appropriately to adjust the axial position of the lower nose 11 with respect to the upper nose 10, and thus the length of the nose 12. A lock nut 19 is provided below the lock nut 18, and the lock nut 19 engages with the above-mentioned male screw formed on the upper portion of the lower portion 11 of the nose.

As shown in FIG. 2, the retaining ring 18 has notches on both sides.
18b, and the outer periphery of the adjusting nut 17 is exposed from the notch 18b. Therefore, the position of the adjusting nut 17 can be adjusted and the length of the nose 12 can be changed by loosening the lock nut 19 and operating the adjusting nut 17 from the notch 18b of the stop nut 18. In order to prevent relative rotation of the nose upper part 10 and the nose lower part 11, an axial groove 10a is formed in the nose upper part 10 and an axial groove 11a is formed in the nose lower part 11, and these grooves 10a, 11a are formed. Guide pin 28 is inserted in.

A pair of chuck members 20 are attached to the nose lower portion 11 on opposite sides in the diametrical direction. As shown in FIGS. 2 and 3, the chuck member 20 is swingably attached to the nose lower portion 11 by a pin 21. A semi-conical surface 20a is formed at the tip of the chuck member 20. Normally, the semi-conical surfaces 20a are in a position where they are abutted against each other as shown in FIGS. 20
A conical guide surface is formed by a. A compression spring 22 is arranged between each chuck member 20 and the lower part 11 of the nose, and urges the chuck member 20 to the position shown in FIGS. The nail 23 to be driven is in the position shown in FIG. 4 in the filled state, the head is hooked on the upper part of the conical guide surface and locked, and the shaft portion projects downward from the lower end portion of the chuck member 20. When the nail 23 is driven downward by the blade 8 from this state, the nail 23 hits the surface 20a and pushes the lower ends of the chuck members 20 open to each other, and the nail 23 is driven toward the target object.

A latch mechanism is provided in order to prevent the chuck member 20 from being opened due to the weight of the nail 23 in the filling position except when the chuck member 20 is driven. For this purpose, the chuck member 20 is formed with a step portion 20b on one side which is recessed laterally outward. As shown in FIGS. 1 and 2, a latch lever 24 is swingably attached to a lower portion 11 of the nose 12 by a pin 25 at an upper end portion thereof. Latch lever
As shown in FIG. 6, 24 has a pair of claws 24a at the lower end thereof, and these claws 24a are in the closed position.
It is formed with a space so as to come to a position corresponding to the stepped portion 20b. The latch lever 24 is biased by the torsion spring 26 to a position where the lower end claw 24a engages with the step portion 20b of the chuck member 20.

A roller 27 is rotatably supported in the middle of the latch lever 24, and the roller 27 is formed in a hole 11b formed in the lower part 11 of the nose.
A part thereof projects through the hollow inside of the lower part 11 of the nose. Due to the driving of the nail 23, the blade 8 is at the lower part of the nose 11
When moving downward in the inside, the blade 8 hits the roller 27 to rotate the latch lever 24 counterclockwise in FIG. By this rotation, the claw 24a of the latch lever 24 is disengaged from the stepped portion 20b of the chuck member 20, and the chuck member 20 can rotate around the pin 21.

As shown in FIG. 1, a filling port 29 for the nail 23 is provided on the lower part 11 of the nose.
Is provided. A filling fitting 30 is attached to the filling port 29, and the filling fitting 30 is connected to a known nail supply device (not shown). The nails 23 to be driven are supplied to the lower part 11 of the nose one by one, and are held in a filling position which is hooked on a conical guide surface formed between the chuck members 20 as shown in FIGS. 1 and 4. At the time of operation, first, the trigger 6 is pulled so that the tip of the nail 23 protruding from the tip of the chuck member 20 is aligned with the pilot hole formed on the nailing surface. In the process of aligning the tip of the nail 23 with the pilot hole. It is conceivable that the nail 23 is pushed back in the lower part 11 of the nose in the opposite direction. In order to prevent such reverse pushback, nails
23 detents are provided. This detent is constituted by a detent lever 31. The upper end of the lever 31 is swingably attached to the lower part 11 of the nose by a pin 32.
The detent lever 31 extends obliquely downward, and the lower end thereof projects into the hollow inside of the nose lower portion 11. A step portion 31a is formed at the lower end portion of the detent lever 31. Further, the detent lever 31 is biased by the torsion spring 33 in the counterclockwise direction in FIG. 1, that is, in the direction in which the lower end of the lever 31 projects into the lower part 11 of the nose. The force of the spring 33 is relatively weak, and when the nail 23 is filled, the weight of the nail 23 pulls the tip of the lever 31 from the hollow inside of the lower part of the nose. A stopper 31b is provided on the lower part 11 of the nose to limit the range of rotation of the lever 31 that occurs at this time. After the nail 23 has passed, the lever 31 is again in the first position.
Returning to the position shown in the figure, in this position, when the nail 23 is about to be pushed back, the tip of the lever 31 engages with the head of the nail 23 to prevent the nail 23 from being pushed back in the opposite direction.

7 to 9 show the shape of the nail driving blade 8 used in this embodiment. The upper end of the blade 8 is formed with a screw hole 8a into which a screw for connecting to the driving piston 4 is inserted, and in the middle,
Grooves 8b are formed to both reduce the weight and guide the blade. The groove 8b has a cross-sectional shape as shown in FIG. 8, and the guide pin 34 inserted in the nose upper portion 10 in the radial direction is slidably engaged with the groove 8b. With this structure, the blade 8 and the nose 12 are combined so as to be slidable in the axial direction but not capable of relative rotation. At the lower end of the blade 8, a groove 8c having a rectangular cross section, which is smaller than the groove 8b, is formed as shown in FIG. The groove 8c has a size that allows the end portion of the detent lever 31 protruding into the lower portion 11 of the nose to pass therethrough. The shape of the blade 8 can reduce the weight of the blade 8, prevent relative rotation between the blade 8 and the nose 12, and ensure a sufficient cross section for nail driving at the end. It is useful in terms.

Fig. 10 shows the lower part of the cylinder housing 2 and the upper part of the nose 10
Shows the relationship with. A long hole 10b for a locking pin that is long in the axial direction is formed on the side surface of the nose upper portion 10, and a locking pin 35 that engages with this long hole 10b is provided in the lower portion of the housing 2. The stop pin 35 is biased by a spring 36 inward in the radial direction, that is, in the engagement direction. A hole 2a is formed in the housing 2 at a height corresponding to the guide pin 34. This hole 2a
Is at a position displaced in the rotational direction with respect to the guide pin 34 at the position where the stop pin 35 engages with the elongated hole 10b of the nose upper portion 10. When disassembling the device, the stopper pin 35 can be pulled out from the elongated hole 10b, the nose upper portion 10 can be rotated with respect to the housing 2, the guide pin 34 can be aligned with the hole 2a, and then the pin 34 can be pulled out from the groove 8b. .

As shown in FIG. 10, if a plurality of elongated holes 10b that engage with the stop pins 35 are provided in the nose upper portion 10 at positions displaced in the circumferential direction, the position of the filling metal fitting 30 with respect to the nail driving machine is appropriately set. It will be possible to change.

As shown in FIG. 1, a safety device yoke 37 is secured between the threaded ring 16 and the lock nut 18 on the nose top 10. The yoke 37 engages with the lock mechanism 39 of the trigger 6 and releases the lock mechanism of the trigger 6 when the nose 12 is pushed axially from the position shown in FIG. A spring 40 is arranged between the lower end of the housing 2 and the threaded ring 16 on the upper part of the nose 10 so that the nose 12
Is urged in the direction of pushing it out of the housing 2. further,
As shown in FIGS. 1 and 2, at the lower end of the lower part 11 of the nose, there is provided a nose piece or pad 41 which is pressed against the surface to be nailed.

In the operation of this device, as mentioned above, the nail 23
Each book is supplied to the filling port 29. The nail 23 is a detent lever
31 is pushed away to pass through the lower end of the lower nose 11 and is held by the chuck member 20 at the lower end of the lower nose 11 as shown in FIGS. 1 and 4. Here, the tip of the nail 23 projects downward from the lower end of the chuck member 20,
The nail 23 is positioned so that the tip of the nail 23 fits into the pilot hole formed in the surface to be nailed. At this time, the detent lever 31 engages with the head of the nail 23 and prevents the nail 23 from being pushed back inward within the lower portion 11 of the nose. When driving the nail 23 into the surface having no pilot hole, it is necessary to reduce the amount of protrusion of the nail 23 from the tip of the chuck member 20. In this case, when a slightly strong force is applied to the tip of the nail 23 in the pushing direction, the head of the nail 23 engages with the slope of the tip of the detent lever 31 to move the detent lever 31 to the first position. Rotate clockwise in the figure. Then, the head of the nail 23 is detented
It is stopped at a position where it engages with the stepped portion 31a of 31. In this position,
The nail 23 is detented by the step portion 31a of the detent lever 31.

Then, the pad 41 of the lower part 11 of the nose is pressed against the surface to be nailed, and the nose 12 is pressed in the direction of the housing 2 against the action of the spring 40. By this operation, the yoke 37 is pushed upward in FIG. 1, and the lock mechanism 39 of the trigger 6 is released. Next, the driving piston 4 is actuated in the driving direction by pulling the trigger 6.

By the operation of the driving piston 4, first, the tip of the blade 8 hits the roller 27 on the latch lever 24, and
24 is driven in the unlatching direction so that the chuck members 20 can rotate in directions away from each other. At this time, the latch lever 24 is suddenly driven in the unlatching direction, but in order to prevent the latch lever 24 from excessively rotating, a stopper 24b is provided at the lower portion 11 of the nose. Then, the tip of the blade 8 engages with the head of the nail 23 to drive the nail 23 in the driving direction. By driving the nails 23, the chuck members 20 are driven in directions away from each other to allow the nails 23 to pass. When the driving piston 4 reaches the vicinity of the bottom dead center indicated by the broken line 4a in FIG. 1, the lower surface of the driving piston 4 hits the upper cushioning material 13 of the auxiliary piston 9, and a part of the impact force of the driving piston 4 is absorbed by the cushioning material 13. Is transmitted to the sub piston 9 via.

In the state before driving, a gap of several mm is provided between the sub piston 9 and the cushioning material 14, and the space formed by this gap serves to buffer the impact force of the driving piston 4.
The sub-piston 9 is driven downward by the driving piston 4 and hits the cushioning material 14, but as the sub-piston 9 moves during this time, the yoke 37 also moves downward, and the safety device is locked again.

The position of the lower end of the blade 8 at the bottom dead center of the driving piston 4 and the blade 8 is substantially flush with the lower surface of the pad 41 when the nose 12 is pushed against the housing 2 against the action of the spring 40. It is preferable that For this purpose, it is necessary to adjust the length of the nose 12, and the adjusting nut 17 described above is operated as necessary. When the tip of the driving blade 8 is almost in contact with the surface to be nailed, a part of the impact force of the driving piston 4 is transmitted from the nose 12 to the pad 41 via the sub piston 9, so that the impact force of the driving is achieved. Is distributed over a wide area of the nailed surface, and the possibility of destruction due to the concentration of local impact force on the surface is greatly reduced.

When the striking piston 4 reaches the bottom dead center of the striking stroke, the compressed air passage in the cylinder housing 2 is switched by a well-known structure, an upward fluid pressure acts on the striking piston 4, and the striking piston 4 moves upward. Driven.

[Effect]

As described above, in the power nailing machine of the present invention,
A sub-piston is provided in the fluid cylinder below the driving piston, and the sub-piston is arranged so as to hit the driving piston near the bottom dead center of the driving piston. It is possible to prevent the impact force from the blade from concentrating locally on the nail driving surface and prevent the nail driving surface from being broken during driving.

[Brief description of drawings]

FIG. 1 is a sectional view of a power nailing machine showing an embodiment of the present invention, FIG. 2 is a front view of the power nailing machine shown in FIG. 1, and FIG. 3 is a front view of a chuck mechanism. 4 is a sectional view showing a part of the chuck mechanism, FIG. 5 is a plan view of a chuck member, FIG. 6 is a perspective view of a latch lever, FIG. 7 is a side view of a driving blade, and FIG. FIG. 9 is a sectional view of an intermediate portion of a driving blade, FIG. 9 is a sectional view of a tip portion of a driving blade, and FIG. 10 is a sectional view showing a relationship between a cylinder housing and a nose. 2 ... Cylinder housing, 3 ... Cylinder bore, 4 ... Driving piston, 6 ... Trigger, 9 ... Secondary piston, 10 ... Nose upper part, 11 ... Nose lower part, 12 ... Nose, 20 ... Chuck member , 24 …… Latch lever.

Claims (7)

[Claims] 1. A fluid cylinder, and a driving piston axially slidably disposed in the fluid cylinder,
In a power nailing machine in which a blade for nailing is attached to the driving piston, and the blade is guided by a nose provided at the tip of the cylinder, in the fluid cylinder, below the driving piston. An auxiliary piston slidable in the axial direction of the fluid cylinder is installed so as to hit the driving piston near the bottom dead center of the driving piston, the nose is attached to the auxiliary piston, and the tip of the nose is A power nailing machine characterized by having a nose piece pressed against the surface to be nailed. 2. The power nailing machine according to claim 1, wherein the auxiliary piston has a first cushioning material attached to a side facing the driving piston, and the first cushioning material is attached to the auxiliary piston. A power nailing machine in which a second shock absorbing material is arranged in the fluid cylinder on the side opposite to the above. 3. The power nailing machine according to claim 2, wherein the first cushioning material is harder than the second cushioning material. 4. The power nailing machine according to any one of claims 1 to 3, wherein a tip surface of the nose piece, which is to be nailed, is substantially flush with the bottom dead center position of the blade tip. Powered nailer located. 5. The power nailing machine according to claim 1, wherein the length of the nose is adjustable so that the position of the nose piece with respect to the sub piston can be adjusted. Power nailer. 6. The power nailing machine according to claim 1, wherein the nose is integral with the sub piston or an upper hollow shaft portion connected to the sub piston.
A power nailing machine comprising a lower hollow shaft part connected to the upper hollow shaft part by unfastening an adjusting nut so that the length in the axial direction can be adjusted. 7. The power nailing machine according to any one of claims 1 to 6, wherein a gap is provided below the sub piston when the sub piston is at the top dead center position. A power nailing machine provided with a cushioning material.