JPS59182008A - Vibration drill - Google Patents

Abstract

PURPOSE:To increase a shock force and reduce the fatigue of a worker by constituting so that the spring constant during vibration is made larger than the spring constant used for depression until the vibration is started. CONSTITUTION:Two springs 14a, 14b are provided in a layers between the first and the second vibration plates 12, 13 in a vibration drill boring through a hard and fragile material such as concrete. One end of these springs 14a, 14b is coupled with the inner bottom surface of a vibration housing 3 fixed with the plate 12, the other end of the spring 14a is brought into contact with the fitting section of the plate 13, and the other end of the spring 14b is put in a free and released condition at this side from the other end of the spring 14a by delta2. That is, the spring constant during vibration is made larger than the spring costant used for depression until the vibration is started. Accordingly, the shock force is increased and also the fatigue of a worker can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a vibratory drill that increases impact force and reduces operator fatigue.

(Background Art) When drilling into hard and brittle materials such as concrete, simply applying weight to the drill bit and applying rotation is inefficient, so a method of repeatedly applying impact force to the rotating shaft is used.

FIG. 1 shows the configuration of a conventional vibratory drill, with main parts shown in cross-section. 2 is a drill body, and the drill body 1 is mainly composed of a body housing 2 and a vibration housing 3. A four-piece rotating shaft is shown, and a drill bit 6 is attached to the tip by a chuck 5.
The rotating shaft 4 is rotatably attached to the drill body 1 by a bearing 7.8. Note that the bearings 7 and 8 are loosely fitted on either the rotating shaft side or the drill body side, so that the rotation ζ 114 can also slide in the axial direction. Further, 9 indicates a motor, which provides rotation to the rotating shaft 4 via a pinion gear 0 and a reduction gear 11.

On the other hand, 12 and 13 are a pair of diaphragms, and the first diaphragm 121'l is fixed to a vibration housing 3 that is a part of the nitrile body 1, and is slidably fitted to the rotating shaft 4. The second diaphragm 13 is fixed to the rotating shaft 4,
Due to the repulsive force of the spring 14, the 92 diaphragms 12 and 13 are normally spaced apart from each other in the axial direction and face each other. Note that the diaphragm 12
, 13 is disk-shaped as shown in Fig. 2, and one end surface thereof is provided with continuous unevenness in the circumferential direction, and as shown in Fig. 3, the engagement position changes with rotation, and the axial direction A displacement corresponding to the difference δ1 in unevenness is repeatedly generated.

Further, in FIG. 1, 15 is a power switch, and 16 is a power cord.

In operation, when the power switch is turned on, the motor 9
rotates, and rotational power is applied to the rotating shaft 4 via the binion lO1 reduction gear 11. In this state, drill bit 6
When the drill body 1 is pressed against a material such as a concrete wall, the rotary shaft 4 slides toward the body (to the left in the figure) against the repulsive force of the spring 140, and the first. The second diaphragms 12 and 13 come into contact and engage with each other. However, since the first diaphragm 12 is fixed to the main body,
As the diaphragms 12 and 1.3 collide and run over the ridges of the diaphragms 12 and 1.3 as they rotate, vibrations in the axial direction are given to the rotation 4 and 14. If the period of vibration at this time is δ1, and the spring constant of the spring 14 is 1, then , E = LK1δ1' (1) 2 The energy expressed as It is designed to give an impact force.

By the way, in the above-mentioned conventional vibration drill, the impact energy is given by the above equation (1), and the spring constant of 1 is determined within the range that can be held down by hand, so the energy E1 is relatively small. shi, other impact tools,
For example, the impact force is weak compared to well-known hammer drills, etc., so it takes time to drill holes, and the drill body has to be pressed strongly against the material, which results in tiring work and vibrations in the hands. It has the drawback of being susceptible to so-called vibration disease because of the strong transmission and long working time. In addition, in order to improve the above-mentioned drawbacks, if we try to increase the energy E, and increase the difference in δ1 during vibration, that is, the unevenness of the diaphragm, too much, the load on the diaphragm becomes excessive9, and the allowable stress of the diaphragm material. It will be destroyed in a short period of time. Furthermore, if the shaft is simply made thicker, the rotating shaft will not slide unless a large force is applied, resulting in hand fatigue. The above drawbacks are particularly noticeable when drilling holes in ceilings etc. from below, making conventional vibrating drills extremely difficult to use.

(Objective of the Invention) The present invention has been proposed in view of the above points, and provides an imaging camera that increases impact force to improve work efficiency, reduces operator fatigue, and prevents vibration sickness. The purpose is to provide a drill.

(Disclosure of the Invention) FIG. 4 shows an embodiment of the present invention, in which two springs 14a are installed between the first diaphragm 12 and the second diaphragm 13.
, 14b are polymerized. In the figure, one end of two springs 14a and 14b is locked to the inner bottom surface of the vibration housing 3 to which the first diaphragm 12 is fixed, and the other end of the first spring 14a is connected to the second diaphragm. 13, and the other end of the second spring 14b is in contact with the first
The spring 14a is in a freely released state at a position δ2 before the other end of the spring 14a. Moreover, since the other configurations are the same as those shown in FIG. 1, the same parts are given the same reference numerals and the explanation thereof will be omitted.

In operation, after rotational power is applied to the rotating shaft 4, when the drill bit 6 is applied to the material and the drill body 1 is pressed, the rotating shaft 4 slides toward the main body against the repulsive force of the spring. Here, the first. Second diaphragm 12, 13
Since only the first spring 1.4a, which has a small spring constant, is acting within the distance δ2 until the two start contact, the force required for pressing is relatively small. Then, when further pressing is performed, the first and second diaphragms 12 and 13 come into complete contact as shown in FIG. occurs. However, at this time, two springs 14a, 1
4b are acting together, and the energy stored in the spring during one vibration is δ4. 1st. Second spring 14a
, 14b have spring constants of 1. If 2 is set for E2=, CK1+ is 2) δ1 ・−・−・・・・・・(
2), and the force of the second spring 14b, which is thicker and has a larger spring constant than the first spring 1.4a, is applied, so the impact force becomes significantly larger. Generally, the pressing force felt by a person's hand is averaged, so if vibration is started and maintained with a small pressing force, fatigue will be small even if the energy of the vibration is large.

The results of experiments conducted by the inventor are shown below, and it is clear that the impact force is significantly increased compared to conventional vibrating drills.

(Unit [N]) (Effects of the Invention) As described above, the vibration drill of the present invention has a rotary shaft with a drill bit attached to the tip so as to be slidable in the axial direction; a first diaphragm arranged concentrically and fixed to the drill body and provided with continuous unevenness in the circumferential direction; a second diaphragm having continuous irregularities in the circumferential direction corresponding to the first diaphragm; and two springs inserted between the attachment parts of the first and second diaphragms and overlapping each other. Since the spring constant during vibration is larger than the spring constant acting on pressing up to the start of vibration, it is possible to provide a vibrating drill that has a strong impact force and is not tiring.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional vibration drill, Figures 2 and 3 are
4 is a block diagram showing an embodiment of the present invention, and FIG. 5 is a diagram explaining the operation. DESCRIPTION OF SYMBOLS 1... Drill body, 4... Rotating shaft, 6... Drill bit, 1.2, 1.3-... Vibration plate, 14a, 1
4b - spring. Applicant Matsushita Electric Works Co., Ltd.-4:

Claims (2)

[Claims] (1) A rotating shaft with a drill bit attached to the tip so that it can slide freely in the axial direction, and a concave and convex surface that is arranged concentrically with the rotating shaft, fixed to the drill body, and continuous in the circumferential direction. a first diaphragm that is fixed to the rotating shaft and is arranged opposite to the first diaphragm, and has continuous irregularities in the circumferential direction corresponding to the first diaphragm; a second diaphragm provided in the
2 which are inserted between the mounting parts of the diaphragm and overlap each other.
A vibration drill characterized by being equipped with a number of springs. (2) The vibration drill according to claim 1, wherein one of the two springs is shortened in the axial direction to provide a step.