Self-propelled Air-punching Mechanism

Abstract

A self-propelled air-punching mechanism for making holes in soil by its caction, in which a hollow body is provided with a pointed head section with a striker being located within the body and forming therewith front and rear pressure chambers, and the front chamber communicating with an additional space within the pointed head section of the body, thus raising the impact power of the mechanism.

Description

BACKGROUND OF THE INVENTION

The present invention relates to self-propelled percussive mechanisms, and more particularly to self-propelled air-punching mechanisms used for making holes in soil by its compaction.

PRIOR ART

Known in the art is a self-propelled air-punching mechanism to make holes in soil by its compaction, comprising a body pointed on one side thereof, and housing a striker forming a front pressure space located between the body and the outer surface of the striker, with such space at regular intervals communicating with the source of compressed air and the atmosphere, and a rear pressure space located inside the striker in the tail section thereof, and permanently communicating with the compressed air source. The striker imparts impacts to the body while reciprocating under the effect of compressed air delivered to the pressure spaces through an air supply sleeve coacting with the striker, and fixed in the tail section of the body.

Practice has proved that this conventional mechanism does not possess sufficient impact power in heavily compactable soils because of the small volume of the front pressure space.

The object of our invention is to provide a self-propelled air-punching mechanism which has a higher impact power on the account of an increased volume of the front pressure space, without changing the weight of the mechanism.

SUMMARY OF THE INVENTION

Generally there is provided a self-propelled air-punching mechanism to make holes in soil by its compaction, comprising a hollow body having a pointed head section, the body housing a striker defining in the body a front chamber of variable volume, the striker having a tail section in which is provided a rear chamber of variable volume, the striker impacting impacts to the body while being reciprocated therein by compressed air delivered to the chambers through an air supply sleeve located in a rear chamber of the striker, and fixed in the tail section of the body. According to the invention, within the pointed head section of the body is provided a space which communicates with the front chamber of variable volume through channels formed in the body.

The increase of the front chamber's volume in the present mechanism by making the inner space in the pointed head section of the body raises the impact power of the striker without any deterioration of the operational qualities of the mechanism.

Location of the additional volume of the front chamber in the head section permits imparting to the head of the body, without increasing its weight, a more tapered shape which facilitates the process of entry into the soil.

BRIEF DESCRIPTION OF THE DRAWINGS

For better understanding the invention, the following is a detailed description and drawing, in which the sole FIGURE shows a longitudinal section of the punching mechanism.

DETAILED DESCRIPTION OF THE INVENTION

The self-propelled punching mechanism shown in the drawing comprises a body 1 having a pointed front section, with the body consisting of a tip 2, a fairing 3, an anvil 4 secured to body 1, and a cylinder 5.

Located inside the cylinder 5 is a striker 6. The tip 2 of the body 1 is provided with an inner space 2a and disposed between the inner surface of the cylinder 5 and the outer surface of the striker 6 is a front chamber 7 of variable volume, and the chamber 7 through air channels 8 in the anvil 4, communicates with the space 2a. The chamber 7 and the space 2a constitute a single pressure chamber.

Inside the tail section of the striker 6 is provided a space 9 of variable volume, and stepped air supply sleeve 10 is inserted into the space 9, with the space 9 defining the rear pressure chamber of the mechanism.

The walls of the striker 6 are formed with ports 11 to provide communication between the single front chamber 2a, 7, 8 and the rear pressure chamber 9. The stepped sleeve 10 is attached to the tail of the cylinder 5 by means of a flexible coupling 12 and a nut 13. The coupling 12 has channels 14 to exhaust the return air to the atmosphere.

Secured to the rear end of the sleeve 10 is a hose 15 within the sleeve 10 is a channel 16 to supply air to the pressure chambers 2a, 7, 8, and 9.

The mechanism operates as follows:

When compressed air is fed from its source through the hose 15 and the channel 16 into the chamber 9, the striker 6 starts moving inside the body 1 toward the anvil 4, and delivers an impact with the body 1 thus moving forward.

At the end of the direct stroke of the striker 6, the ports 11 coincide with the rear pressure chamber 9, and thus connect the single front pressure chamber 2a, 7, 8 through the chamber 9, the channel 16, and the hose 15, with the source of compressed air.

After its impact against the anvil 4, the striker 6 under the effect of the rebound and the force produced by air pressure in the single front chamber 2a, 7, 8 starts moving back. In the further movement of the striker 6, the ports 11 are closed by the side surface of the sleeve 10.

In the single front pressure chamber 2a, 7, 8, the air expands, thus further moving striker 6a reverse direction. Hence, the striker 6 overcomes the resistance of compressed air in the chamber 9 which is permanently connected with the compressed air source.

The enlargement of the volume of the single front chamber 2a, 7, 8 due to the additional space 2a inside the tip 2 increases the impact energy of the striker.

At the end of the back stroke of the striker 6, its ports 11 having passed the larger diameter step of the sleeve 10 will provide communication between the chamber 2a, 7, 8 and the atmosphere through the channels 14 of the coupling 12.

The air is exhausted, and the cycle is then resumed.

The tests of the mechanism made according to the invention, having the same weight as the conventional mechanism, and a life time of 500-600 hours, proved that its impact energy exceeds that of the conventional mechanism 1.5 times, and equals 45 kgm. At the same time, the frequency of impact has dropped by 20 percent as compared to that in the conventional unit.

Claims

What we claim is:

1. A self-propelled air punching mechanism to make holes in soil by its compaction, comprising: a hollow cylindrical body having a pointed head section, said head section having an inner space and passages, a striker located within said body and defining with the inner surface of the body a front chamber of variable volume, said front chamber communicating periodically with a compressed air source and atmosphere, said striker having a tail section having openings in the side wall and a cavity, an air-passing sleeve slidably mounted in the cavity, said sleeve and cavity defining a rear chamber of variable volume which is permanently connected to a compressed air source and which, upon interaction with said striker, supplies air into said chambers and into the inner space and passages in the pointed head section of the body, as a result of which the striker moves reciprocally and imparts impacts to said body.