JPS6029434Y2 - Dry-driving prevention mechanism for hammer drills, etc. - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an all-round prevention mechanism for hammer drills, etc.

Conventionally, as for the above-mentioned whole village prevention mechanism, the tip of the hammer is formed into a tapered part, while the front part of the cylinder is provided with an uneven part, and when the hammer moves forward with no load, the tapered part of the hammer fits into the above-mentioned uneven part. Some devices are known in which the hammer is stopped at the forward position by
In order to stop the hammer reliably, it is necessary to make an interference fit between the taper part and the uneven part, so if you do this, when you install the tool at the start of work, you will have to use a strong force to remove the fitting with the tool. If the above fitting holding force is weakened to make it easier to attach the tool, the hammer will not be able to stop due to the hammer's own weight, pressure changes due to the piston, etc., or the reaction force when it moves forward and hits the piston. Since the original purpose of the whole village prevention mechanism cannot be achieved remotely, the fitting and holding force of the two mentioned above must be adjusted appropriately, but such adjustment is extremely difficult, and the above holding force decreases as the device is used. There was a problem in that it had to be adjusted each time as it changed.

Therefore, the present invention was developed in view of the above-mentioned conventional problems.
The hammer can be stopped in an optimal state, and the hammer holding force can be easily and accurately adjusted only by adjusting the spring pressure, and variations between products can be reduced, and the structure is simple and can be provided at low cost. A village-wide prevention mechanism was established for the purpose of

The present invention will be described in detail below with reference to drawings showing an example of a hammer drill in which the present invention is implemented.

The first hammer drill is the same as the known hammer drill.
As shown in the figure, compressed air is generated by the reciprocating operation of a piston 1 driven by a drive source (not shown) such as a motor, and this compressed air causes a hammer 3 fitted in a cylinder 2 to reciprocate, The tool 5 is configured to generate a striking force.

Thus, in the entire village prevention mechanism 6 of the present invention, as shown in FIGS. 1 to 3, a hole 7 is formed penetratingly in the front peripheral wall 2a of the cylinder 2, and a stopper ball 8 is loosely fitted into the hole 7. is elastically biased toward the center of the cylinder 2 by a spring 9, and a recess 3a is provided on the outer periphery of the hammer 3 to prevent damage when the tool 5 is removed or the tool 5 comes off the workpiece during work. Hammer 3 by becoming a load
When the hammer 3 moves forward, the stopper ball 8 and the recess 3a engage with each other as shown in FIG. 2, so that the hammer 3 can be stopped at the forward limit.

In this case, the recessed portion 3a is provided around the circumference by making the intermediate portion of the nozzle 3 smaller in diameter as shown in the figure, and this creates a stepped portion between the large diameter portions 3b and 3c at the front and rear portions on the tapered surface 3a. It is shaped so that it can slide inside the cylinder 2, and an O-ring 10 is provided around the large diameter part to airtightly fit into the cylinder 2.The recess 3a and the stopper ball 8 are connected to the hammer 3. The positions and spring pressures are set in advance so that the hammers 3 move forward and engage with each other at the forward limit when they hit the stepped portion 2b of the cylinder 2, and the hammer 3 does not retreat toward the piston due to the reaction force when they hit. This is provided.

Further, as shown in FIG. 3, the hole 7 into which the stopper ball 8 is loosely fitted is shaped so that the inside diameter is slightly smaller than the diameter of the stopper ball 8. The large-diameter portion 3b of the hammer 3 has a front end shaped like a taper 3d. When the taper 3d surface hits the stopper ball 8, the stopper ball 8 can be pressed and retreated smoothly against the spring force, and the stopper ball 8 can be pushed back by moving forward. The surface of the large diameter portion 3b slides and engages with the recess when moving forward or backward.

Further, as the spring 9, a coil spring or a belt-shaped plate spring as shown in the figure is used.

When using the above coil spring, it is best to install it in hole 7 and then support it with a screw plug, etc. When using a plate spring,
As shown in the figure, a recess 11 may be provided on the outer periphery of the cylinder to fit and hold the leaf spring.

In FIG. 1, reference numerals 12 and 13 designate air vent holes formed in the front and rear portions of the cylinder 2, respectively, and 14 designates a sleeve for mounting a tool attached to the tip of the front cap 15.

In the above configuration, when air is intermittently compressed by reciprocating the piston 1 within the driving cylinder 2 by the driving source, the compressed air causes the hammer 3 to impact and impact the tool 5 via the adapter 4. During machining such as drilling holes in the workpiece by generating impact force,
The stopper ball 8 is pressed by the front large-diameter portion 3b of the hammer 3, but the recess 3a does not advance to the position of the stopper ball 8, so they are not engaged with each other, and therefore, operations such as drilling can be performed without any trouble. will be carried out.

Also, during the above-mentioned work, if the tool 5 comes off the workpiece or needs to be removed, if the piston 1 is driven as described above, the nozzle 3 will be under no load, so the compressed air will be removed. Because it is advanced further than during the above-mentioned processing,
The stopper ball 8 is pushed back against the spring force by the large-diameter portion 3b of the hammer 3, advances to the frontmost end, and at the position where it hits the stepped portion 2b of the cylinder 2 matches the recessed portion 3a, thereby spring 9 The hammer 3 is pushed out and engaged with the recess 3a, and the hammer 3 is stopped at the forward limit.

Therefore, full lighting during no-load conditions is prevented. As explained above, according to the full-light prevention mechanism for a hammer drill or the like according to the present invention, the stopper ball 8 disposed in the cylinder 2 and elastically biased by the spring 9 and the hollow 3a provided in the hammer 3 are Since the hammers 3 are engaged with each other at the most advanced position and the hammer 3 can be stopped at the advanced position, not only can all lights be prevented, but also the tool 5
By pushing in with a small force, the stopper ball 8 is moved back against the spring force by the peripheral wall surface of the large diameter part of the hammer 3, and can be easily disengaged from the recess 3a. The hammer holding force due to the engagement of the two above can be easily and easily adjusted by using the spring 9 with an appropriate spring force, so that variations in each product can be extremely reduced. effective.

Furthermore, the mechanism is simple in structure, and the stopper ball 8
can be produced by elastically biasing the spring 9,
Can be provided at low cost.

[Brief explanation of drawings]

FIG. 1 is a partial longitudinal side view of a hammer drill equipped with a full-light prevention mechanism according to the present invention, and FIG. 2 is a longitudinal side view showing the same mechanism in which the hammer is stopped and held at its maximum forward limit.
FIG. 3 is an enlarged sectional view of the main parts of the mechanism. 1...Piston, 2...Cylinder
3...Hammer 3a...Recess, 7.
... Hole, Death ... Stotuber Hole, 9...
・◆・・Spring.

Claims (1)

[Scope of utility model registration request] This is a complete prevention mechanism for hammer drills, etc., in which a hammer 3 is reciprocated by compressed air from a piston 1 to generate a striking force on a tool. 9, the hammer is elastically biased toward the center, and when the hammer moves forward without a load, the stopper ball engages with the recess 3a provided on the outer periphery of the hammer, and the hammer stops moving forward or backward. Whole village prevention mechanism such as hammer drill.