JPH05371U - Strike piston return mechanism of continuous hammering nailer - Google Patents

Abstract

(57) [Summary] [Structure] An effective area difference is formed between the movable cylinder 2 and the housing 3 so that the compressed air supplied into the air chamber 17 acts so as to push the movable cylinder downward. Piston return air chamber 17
The air supply passage 16 that connects the compressed air supply source 9 with the compressed air supply source 9 is connected only when the movable cylinder 2 is raised. [Effect] Since the compressed air is supplied to the return air chamber 17 after the striking operation, the striking piston 11 surely ascends and returns, and the power per striking increases. In addition, the movable cylinder 2 moves downward and then returns downward due to the returning force based on the effective area difference. At this time, since the switching timing of the compressed air is delayed, the returning performance of the striking piston 11 is improved. Further, since the movable cylinder 2 is free before driving the nail driver, it is not necessary to press the housing 3 in advance.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a continuous hammering type nailing machine in which a movable cylinder is housed in a housing, a striking piston is housed in the movable cylinder, and the striking piston is continuously and repeatedly driven. The present invention relates to a striking piston returning mechanism that reduces the recoil of a housing that accommodates the striking piston when the striking piston is driven, and that reliably returns the striking piston to its original position.

[0002]

[Prior art and its problems]

 In general, a continuous hammering type nailing machine is known in which the same nail is continuously and repeatedly hammered. As one method, the cylinder is moved by the reaction of a striking piston driven to strike the nail, and the upper chamber of the movable cylinder is alternately switched between the compressed air supply source and the exhaust port based on this movement. A mechanism that repeatedly drives the striking piston is adopted. Then, as a mechanism for returning the striking piston that has completed the striking stroke to the upper position in order to re-drive it, an air chamber for accumulating air for the striking piston return air is formed around the movable cylinder, and the striking piston is struck in the air chamber. It is known that compressed air stored during the stroke is supplied to the lower chamber of the striking piston to raise and return the striking piston.

The striking piston returning mechanism is one in which compressed air is supplied into the chamber through a small hole formed in the middle of the movable cylinder. Since it is driven by repeated impacts, the impact piston cannot reach the bottom dead center in the initial impact, and the stroke is returned from the middle, so sufficient compressed air can be accumulated in the air chamber. Therefore, the striking piston cannot be reliably returned.

If the striking stroke is started again in a state where the striking piston does not return to a sufficiently upper position, the striking piston will be striking before sufficient acceleration is applied, so that the striking power becomes small and the same nail is used. There is a problem that the number of hits with respect to increases and the work efficiency decreases.

As a technique for solving this, it may be possible to supply compressed air into the air chamber at an early stage by forming a small hole communicating the inside of the movable cylinder with the air chamber at a position above the cylinder. However, the small hole has a function of releasing the pressure increase in the movable cylinder lower chamber on the lower side of the impact piston during the impact stroke into the air chamber to prevent the impact force of the impact piston from being reduced. Therefore, the small hole cannot be formed at the upper position.

Further, in the continuous hammering type nailing machine using the movable cylinder, in order to return the movable cylinder, which has moved upward by the reaction force, to the lower side, a biasing means such as a compression vane is constantly actuated between the housing and the movable cylinder. ing. Therefore, when the return stroke of the striking piston begins, the movable cylinder immediately descends and operates in the direction to start another striking stroke. The stroke of the striking piston increases as the number of strokes increases (because the nails are driven deeper), and more time is required for the stroke, but the return time of the movable cylinder is constant. Since the supply / exhaust of compressed air is switched according to the movement of the movable cylinder, the striking stroke is started before the striking piston is fully returned, and the striking force becomes small.

[0007]

[The purpose of the device]

 It is an object of the present invention to provide a striking piston returning mechanism that returns a striking piston to a sufficiently upper position to improve the striking force each time and enables a nail to be driven with a small number of striking.

[0008]

[Means for achieving the purpose]

 In order to achieve the above object, a striking piston returning mechanism of a continuous striking type nailing machine according to the present invention accommodates a striking piston and a striking piston slidably and slides to the opposite side from the striking piston by a reaction force of the striking piston. A movable cylinder that moves and a housing that slidably accommodates the movable cylinder are provided. Sliding of the movable cylinder alternately switches the upper chamber of the movable cylinder to a compressed air supply source and an exhaust port. In a continuous hammering type nailing machine configured to repeatedly drive a piston, a return air chamber that communicates with a lower chamber of the movable cylinder located below the striking piston is formed around the movable cylinder. Between the outer peripheral surface of the movable cylinder and the inner peripheral surface of the housing, the movable cylinder is pushed down by the air supplied into the air chamber. And a valve mechanism for forming an air supply path connecting the air chamber and the compressed air supply source and communicating the air supply path only when the movable cylinder is raised. Characterize.

[0009]

[Function and effect of the device]

 According to the above configuration, the air supply path is opened only when the movable cylinder is lifted after the striking operation by the striking piston, the compressed air from the compressed air supply source is supplied into the return air chamber, and the lower chamber of the movable cylinder is further opened. Since it is supplied to the striking piston, the striking piston receives a sufficient pressure from the lower side and surely returns to the original upper position. Therefore, the power per impact by the impact piston is increased, and the nail driving work can be completed in a short time with a small number of impacts, thus improving the work efficiency.

In this regard, during the striking stroke, the air supply passage that connects the compressed air supply source and the return air chamber that communicates with the lower side of the striking piston is completely cut off. Since the pressure does not rise unnecessarily, the impact force cannot be reduced.

Further, since the movable cylinder is pushed down after the striking operation of the striking piston by the effective area difference under the action of the compressed air in the returning air chamber, the movable cylinder is returned to the original lower position without using a means such as a spring. Can be moved back to. Furthermore, during the striking stroke, the downward force is not applied to the movable cylinder, and only when the movable cylinder moves upward and compressed air is introduced into the return air chamber, the movable cylinder exerts the returning force. , The timing at which the movable cylinder rises and the switching of compressed air supply and exhaust alternates is delayed, the timing of transitioning to the impact stroke again is delayed, and the return stroke from near the bottom dead center of the impact piston is delayed. This creates a margin and improves the return performance of the striking piston.

In addition, since the effective area difference for returning the movable cylinder is configured in the return air chamber, the effective area difference actually acts on the return air via the air supply path. After the chamber and the annular chamber are connected, that is, after the compressed air supply source has driven the impact piston to impact the nail, the movable cylinder is in a free state before driving the nail driver and during the impact stroke. Therefore, it is not necessary to push the housing against the return biasing force.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a main part of a continuous hammering type nailing machine, in which 1 is a striking piston, 2 is a movable cylinder, and 3 is a housing. The striking piston 1 is slidably accommodated in a movable cylinder 2 and is integrally connected to a driver 4 that strikes a nail. The movable cylinder 2 accommodates the striking piston 1 slidably and slides on the opposite side to the striking piston 1 by the reaction force of the striking piston 1. The housing 3 is formed integrally with the nailing machine, and slidably accommodates the movable cylinder 2 therein.

An annular chamber 5 is formed between the outer peripheral surface of the movable cylinder 2 and the inner peripheral surface of the housing 3. The annular chamber 5 is formed between an inner annular convex portion 6 formed on the inner peripheral surface of the housing 3 and an annular head valve 7 arranged above the inner annular convex portion 6. The annular chamber 5 is formed to have a width longer than the sliding distance of the movable cylinder 2, and is constantly connected to the compressed air supply source 9 via the compressed air supply port 8 formed in the housing 3. The head valve 7 is normally located at the lower position, and is configured to operate upward in response to the activation operation of the nail driver.

In addition, an upper communication hole 11 communicating with the upper chamber 10 defined by the striking piston 1 is formed in the upper part of the side wall of the movable cylinder 2. Above and below the upper communication hole 11, the upper communication hole 11 is formed. Sealing portions 12, 13 that selectively come into contact with and separate from the inner peripheral surface of the head valve 7 are provided. An exhaust port 14 is formed in the housing 3 above the movable cylinder 2.

Next, on the outer peripheral surface of the movable cylinder 2, a central seal portion 15 is provided at a portion that slides on the inner annular convex portion 6. An outer annular projection 19 is formed at the lower end of the movable cylinder 2 so as to project outward, and a lower seal portion 20 that abuts the inner surface of the housing 3 is provided on the outer peripheral surface of the outer annular projection 19. It is set around. Between the inner annular projection 6 of the housing 3 and the outer annular projection 19 of the movable cylinder 2, the lower chamber 21 of the movable cylinder 2 located below the striking piston around the movable cylinder 2. An air chamber 17 for returning the striking piston 1 is formed in communication with the air chamber 17. A lower communication hole 18 that always communicates with the return air chamber 17 is formed in the lower portion of the side wall of the movable cylinder 2.

A bypass 16 a is formed in a part of the upper portion of the inner peripheral surface of the inner annular convex portion 6 of the housing 3, and the gap between the bypass 16 a and the inner annular convex portion 6 and the movable cylinder 2 is formed. The air supply path 16 is formed by 16b. Therefore, when the movable cylinder 2 is in the lower position, the central seal portion 15 contacts the inner peripheral surface of the inner annular convex portion 6 to close the air supply passage 16, but the movable cylinder 2 rises and When the bypass 16a is crossed, the air supply passage 16 is opened to connect the annular chamber 5 communicating with the compressed air supply source 9 and the return air chamber 17. Thus, the valve mechanism that opens and closes the air supply path 16 by the vertical movement of the movable cylinder 2 is configured.

Here, the diameter of the contact portion a between the central seal portion 15 of the movable cylinder 2 and the inner annular convex portion 6 of the housing 3 is L1, and the diameter of the lower seal portion 20 of the outer annular convex portion 19 of the movable cylinder 2 is When the diameter of the contact portion b with the inner peripheral surface of the housing 3 is L2, when compressed air is being supplied into the return air chamber 17, the compressed air that moves the movable cylinder 2 upward The urging force corresponds to the effective pressure receiving area of the compressed air received by the contact portion a of the diameter L1, and the urging force for moving the movable cylinder 2 downward is the effective pressure receiving area of the contact portion b of the diameter L2. Correspond. Since the contact portion a having the diameter L1 has a smaller effective area than the contact portion b having the diameter L2, the pressure of the compressed air supplied into the air chamber 17 acts to push the movable cylinder 2 downward. Therefore, the movable cylinder 2 is always urged downward.

Next, the operation mode of the nailing machine having the above-mentioned structure will be described. Before the nailing machine is activated, as shown in FIG. 1, the movable cylinder 2 is at the lower end position of the housing 3, and the impact piston 1 is It is located above the movable cylinder 2, and its upper chamber 10 is open to the atmosphere through an exhaust port 14. Here, when the nail driver is started and the head valve 7 is moved upward as shown in FIG. 2, the head valve 7 is separated from the seal portion 13 provided on the upper portion of the movable cylinder 2 and the seal portion is released. Abut 12. As a result, the connection between the upper communication hole 11 of the movable cylinder 2 and the exhaust port 14 is cut off, and the annular chamber 5 communicating with the compressed air supply source 9 is opened to the upper chamber 10 of the movable cylinder 2 via the upper communication hole 11. Therefore, compressed air is rapidly supplied to the upper chamber 10, the striking piston 1 is driven, and the driver 4 strikes a nail (not shown). At this time, the movable cylinder 2 moves upward in the opposite direction due to the reaction force of the striking piston 1 being driven downward. At the same time, the downward movement of the impact piston 1 compresses the air in the lower chamber 21 of the movable cylinder 2, a part of which is discharged to the outside of the movable cylinder 2, and the other part is returned through the lower communication hole 18. It is supplied into the air chamber 17. In the striking stroke of the striking piston 1, the central seal portion 15 of the movable cylinder 2 abuts the inner annular convex portion 6 of the housing 3 to maintain the sealed state and close the air supply passage 16. There is no inflow of compressed air from the annular chamber 5 into the air chamber 17, so the striking force of the striking piston 1 is not reduced.

While the movable cylinder 2 is moving upward due to the recoil of the striking piston 1 at the time of striking, as shown in FIG. 3, the seal portion 12 provided on the upper portion of the movable cylinder 2 separates from the head valve 7 and seals. Since the portion 13 contacts the head valve 7, the upper chamber 10 of the movable cylinder 2 is again connected to the exhaust port 14 of the housing 3 through the upper communication hole 11, and the upper chamber 10 is rapidly exhausted by exhausting compressed air to the atmosphere. Decompress. On the other hand, in the lower chamber 21 of the movable cylinder 2, the volume is sharply reduced by the striking operation of the striking piston 1, and the pressure is increased. 21 and the pressures of the upper chamber 10 and the lower chamber 21 are reversed, and the movable cylinder 2 rises to open the air supply passage 16 and the compressed air in the annular chamber 5 is returned to the return air chamber 17. Since it is supplied and further supplied from the lower communication hole 18 to the lower chamber 21 of the movable cylinder 2, the striking piston 1 receives a sufficient pressure from the lower side and surely returns to the original upper position. The reverse of the pressure balance between the upper chamber 10 and the lower chamber 21 acts on the movable cylinder 2 so as to brake its rise, and the movable cylinder 2 stops at the upper position.

By the way, as described above, the diameter L1 of the contact portion a between the central seal portion 15 of the movable cylinder 2 and the inner annular convex portion 6 of the housing 3 is smaller than that of the outer annular convex portion 19 of the movable cylinder 2. Since the diameter L2 of the contact portion b between the lower seal portion 20 and the inner peripheral surface of the housing 3 is smaller, the effective area in which the compressed air in the return chamber 17 acts on the movable cylinder 2 is Is bigger. Therefore, due to this effective area difference, the compressed air acts to move the movable cylinder 2 downward, and the movable cylinder 2 returns to the bottom dead center again due to the compressed air.

While the movable cylinder 2 is returning to the bottom dead center, as shown in FIG. 2, the seal portion 13 of the movable cylinder 2 separates from the head valve 7 and the seal portion 12 abuts on the movable cylinder 2. Compressed air from the compressed air supply source 9 is rapidly supplied to the upper chamber 10, the striking piston 1 is driven downward, and the movable cylinder 2 is moved upward by the reaction force thereof. In this way, as long as the head valve 7 is in the upper position, the upper chamber 10 of the movable cylinder 2 is alternately switched between the compressed air supply source 9 and the atmosphere, and the striking piston 1 is repeatedly driven. When the head valve 7 is returned to the lower position in FIG. 1, the upper communication hole 11 of the upper chamber 10 of the movable cylinder 2 is maintained in the state of being connected to the atmosphere through the exhaust port 14, and the compressed air is not switched. Therefore, the striking operation of the striking piston 1 also stops.

As described above, the recoil of the striking piston 1 at the time of striking is absorbed by the operation of the movable cylinder 2 and canceled out, and the recoil is not transmitted to the housing 3, so that the operability is good.

Further, the air supply passage 16 is opened only when the movable cylinder 2 is lifted after the striking operation by the striking piston 1, the compressed air in the annular chamber 5 is supplied into the returning air chamber 17, and the lower communicating hole is further provided. Since it is supplied to the lower chamber 21 of the movable cylinder 2 from 18, the striking piston 1 receives a sufficient pressure from the lower side and reliably returns to its original upper position. Therefore, the power per impact by the impact piston 1 is increased, and the nail driving work can be completed in a short time with a small number of impacts, and the work efficiency is improved.

In connection with this, during the striking stroke, the air supply passage 16 connecting the compressed air supply source 9 and the return air chamber 17 communicating with the lower side of the striking piston 1 is completely cut off, so Since the pressure in the air chamber 17 does not rise unnecessarily, the striking force is not reduced.

Furthermore, since the movable cylinder 2 is pushed down after the striking operation of the striking piston 1 by the effective area difference under the action of the compressed air in the returning air chamber 17, the movable cylinder 2 can be restored to the original state without using a means such as a spring. Can be moved back to the lower position. In addition, during the striking stroke, the movable cylinder 2 is not acted upon by the downward returning force, and the movable cylinder 2 moves upward and compressed air is introduced into the returning air chamber 17 before the movable cylinder 2 is moved. Since the return force acts, the timing at which the movable cylinder 2 rises to switch compressed air supply and exhaust is delayed, and the timing to move to the impact stroke again is delayed, and the impact piston 1 is near the bottom dead center. Since there is a time margin in the return stroke from, the returning performance of the striking piston 1 is improved.

In addition, since the effective area difference for returning the movable cylinder 2 is configured in the return air chamber 17, the effective area difference actually acts via the air supply passage 16. After the return air chamber 17 and the annular chamber 5 are connected, that is, after the compressed air supply source 9 drives the striking piston 1 to strike the nail, the movable cylinder is driven before driving the nailer and during the striking stroke. Since No. 2 is in a free state, it is not necessary to push the housing 3 back against the biasing force.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing a state before a reaction reducing mechanism of a continuous hammering type nailer of the present invention is operated.

FIG. 2 is a cross-sectional explanatory view of a state immediately after driving a striking piston of the nail driving machine.

FIG. 3 is an explanatory cross-sectional view of a state after being hit by a hitting piston of the nail driver.

[Explanation of symbols]

 1 Strike Piston 2 Movable Cylinder 3 Housing 5 Annular Chamber 9 Compressed Air Supply Source 10 Upper Chamber 12 Lower Chamber 16 Air Supply Channel 17 Air Chamber for Returning the Stroke Piston

Claims (1)

Claims for utility model registration: 1. A striking piston, a movable cylinder that slidably accommodates the striking piston and slides on the side opposite to the striking piston by the reaction force of the striking piston, and the movable cylinder. A slidable housing, wherein the movable cylinder slides to alternately switch the upper chamber of the movable cylinder to a compressed air supply source and an exhaust port to repeatedly drive the striking piston. In the nailing machine, a return air chamber communicating with a lower chamber of the movable cylinder located below the striking piston is formed around the movable cylinder, and an outer peripheral surface of the movable cylinder and an inner peripheral surface of the housing are formed. In between, an effective area difference that acts to push down the movable cylinder downward by the compressed air supplied into the air chamber is formed. In addition, a continuous hammering nailing method is characterized in that an air supply path connecting the air chamber and the compressed air supply source is formed, and a valve mechanism is provided for communicating the air supply path only when the movable cylinder is raised. The blow piston return mechanism of the machine.