GB1575650A

GB1575650A - Percussive drilling devices

Info

Publication number: GB1575650A
Application number: GB54397/77A
Authority: GB
Original assignee: Institut Gornogo dela Sibirskogo Otdelenia Akademii Nauk SSSR
Current assignee: Institut Gornogo dela Sibirskogo Otdelenia Akademii Nauk SSSR
Priority date: 1977-12-31
Filing date: 1977-12-31
Publication date: 1980-09-24
Also published as: FR2415417A7; AT350002B; CH629279A5; ATA922577A

Abstract

A cylindrical body (1) has a conically pointed head part (2), adjoining which is a rod (6) which at its end has a conical head (7) which has two surfaces (8) parallel to one another. The body (1) carries a pointed hollow attachment (3) which has a transverse wall (4) in its interior. Arranged in the transverse wall (4) is a profiled aperture (10) through which the conical head (7) can be inserted like a key. The conical head (7) is locked in the hollow space of the attachment (3) by turning the body (1) about its axis through an angle of about 90 DEG , so that the attachment (3) driven into the bore to be made can be pulled out of the bore again by means of the body (1). On the other hand, the attachment (3) can be easily separated from the body (1) by the conical head (7) and the aperture (10) being brought into line again. Such a device enables the attachment (3) to be recovered and reused. <IMAGE>

Description

(54) IMPROVEMENTS IN OR RELATING TO PERCUSSIVE DRILLING DEVICES (71) We, INSTITUT GORNOGO DELA SIBIRSKOGO OTDELENIA AKADEMII NAUK SSSR, a Corporation organised and existing under the laws of the Union of Soviet Socialist Republics, of Krasny prospekt, 54, Novosibirsk, U.S.S.R., do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to percussive action devices for drilling holes in soils.

According to the present invention there is provided a percussive action device for forming holes in soil by compaction, the device comprising a housing with a tapering portion and a head portion, and a hollow tip having a pointed front end and a transverse partition therein, the head portion of the housing being arranged to co-operate with the transverse partition to form a releasable coupling between the housing and tip.

A percussive action device embodying the invention will now be particularly described by way of example with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a side elevation, partly in section, of the percussive action device; Figure 2 is a section on line II-II of Figure 1; Figure 3 is a section on line III-III of Figure 1; and Figure 4 is a perspective view of a portion of the device of Figure 1 to an enlarged scale.

The illustrated percussive action device comprises a housing 1 (Fig. 1) with a conically tapering portion. The conical or tapering surface 2 of the housing 1 is arranged to fit snugly into the rear end of a hollow tip 3 having a pointed front end. The pointed end of the tip 3 directly contacts the soil surface during a drilling operation.

A transverse partition 4 is provided in the tip 3 in the region of the rear end thereof.

The partition 4 is arranged to co-operate with a head portion of the housing to form a releasable coupling between the tip 3 and the housing 1.

The percussive action device can incorporate any suitable known drive means for advancing the device into a hole being drilled and for withdrawal of the device to the mouth of the hole at the end of the drilling operation.

In the described embodiment of the percussive action device, a pneumatic drive, is incorporated.

The tip 3 is hollow to reduce the weight of the device. The shape of the tip 3 in cross-section is arbitrary; however, a cylindrical shape is preferred. The diameter and length of the tip 3 are selected to correspond to the diameter of the whole to be drilled.

As the diameter of the tip 3 is increased, its length is preferably increased also to stabilize the percussive action device in the hole and to facilitate the maintenance of a predetermined direction of drilling.

It is preferable that the external diameter of the tip 3 should be somewhat smaller than the external diameter of the housing 1.

This ensures good engagement of the housing 1 with the wall of the hole, and thus prevents accidental detachment of the housing 1 from the tip 3 during operation of the device.

The portion of the internal surface 5 of the tip 3 in contact with the tapering surface 2 of the housing 1 is also tapered. The taper angle of the contacting surfaces 5,2 of the tip 3 and of the housing 1 respectively, are the same. This ensures good contact between the tip 3 and the housing 1 while a hole is being drilled.

The head portion of the housing 1 comprises an axially projecting stem 6 and a tapering head 7, the latter being attached, to the stem 6 by its narrow end. The tapering head 7 has two parallel flat surfaces 8 (Figs. 2 and 4) and two tapering surfaces 9.

The transverse partition 4 of the tip 3 has an axial opening 10 with a tapering surface 11 and two laterally extending slots 12. The slots 12 (Figs. 2, 3 and 4) are arranged so that the widest portion of the tapering head 7 can pass through the axial opening 10 when the tapering head 7 is in a predetermined angular orientation.

The tip 3 is connected to the housing 1, as follows. The widest portion of the tapering head 7 is aligned with the slots 12 of the axial opening 10 in the transverse partition 4.

The head 7 is inserted together with the stem 6 through the axial opening 10 until the tapering inner surface 5 of the tip 3 contacts the tapering surface 2 of the housing 1. Then the tip 3 and the housing 1 are rotated relative to each other (through about 90 ), so that the tapering surfaces 9 and 11 of the tapering head 7 and of the axial opening 10 respectively are facing each other, as shown in Figure 4.

The length of the stem 6 is such that when the tip 3 is seated on the housing 1 with the surfaces 5 and 2 in contact, the tapering surfaces 9 and 11 of the tapering head 7 and of the axial opening 10 respectively do not engage each other. These surfaces 9, 11 will normally not engage each other throughout a hole-drilling operation, since contact between the surfaces 5 and 2 is necessary to ensure that an impact is transmitted from the housing 1 to the tip 3.

However, when the percussive action device is moved in reverse to retract it from a hole, the tapering surfaces 9, 11 of the tapering head 7 and of the transverse partition 4, respectively, do engage each other, and so the tip 3 is moved with the housing 1 and can be recovered from the drilled hole.

The described percussive action device for drilling holes in soil operates, as follows.

Prior to drilling a hole, the tapering surface 5 of the tip 3 is seated onto the tapering surface 2 of the housing 1. Depending on the actual operating conditions, the pointed end of the tip 3 is either placed directly onto the soil, or else inserted into a pre-formed hole. Then the percussive-action device is energized, and the hole is drilled.

Repeated impacts are transmitted by the housing 1 to the tip 3 which penetrates the soil, moving the housing 1 with it. The peripheral surface of the wall of the housing 1 engages the soil and shapes the wall of the hole. When a hole of the required length has been drilled, the motion of the percussive action device is reversed, whereby the tapering surfaces 9 and 11 of the tapering head 7 and of the transverse partition 4 respectively engage each other, and so allow the tip 3 to be recovered from the hole.

Following the withdrawal of the device from the hole, the tip 3 can be easily detached from the housing 1.

The above described device can be used most effectively to drill holes in compactible soils. It can also be used in geological surveys for taking soil samples by suitable adaptation of the tip 3.

The described connection between the tip and the housing enables the tip to be withdrawn from blind holes and, should it be necessary, to be detached from the housing and replaced by other tools or attachments.

The described releasable connection also ensures reliable fixing of the tip on the housing throughout the hole-drilling cycle, and also for rapid and easy detachment of the tip from the housing, when the device has been retracted from the hole.

WHAT WE CLAIM IS 1. A percussive action device for forming holes in soil by compaction, the device comprising a housing with a tapering portion and a head portion, and a hollow tip having a pointed front end and a transverse partition therein, the head portion of the housing being arranged to co-operate with the transverse partition to form a releasable coupling between the housing and tip.

2. A percussive action device according to claim 1, wherein the rear end of the hollow tip is arranged to seat on the tapering portion of the housing during a hole forming operation.

3. A percussive action device according to claim 1 or claim 2, in which the transverse partition of the tip and the housing head portion are releasable couplable by relative rotation therebetween.

4. A percussive action device according to claim 3, wherein the head portion of the housing comprises an axially extending stem and a head, and the transverse partition of the hollow tip is provided with an opening, said head and opening being so formed that the head can pass through the opening only when the head is in a particular angular orientation relative thereto.

5. A percussive action device according to claim 4, wherein the opening in the transverse partition includes a tapering portion and the head of the housing has tapering surfaces which are arranged to engage the tapering portion of the opening during reverse movement of the device.

6. A percussive action device for forming holes in soil, substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. head 7 has two parallel flat surfaces 8 (Figs. 2 and 4) and two tapering surfaces 9. The transverse partition 4 of the tip 3 has an axial opening 10 with a tapering surface 11 and two laterally extending slots 12. The slots 12 (Figs. 2, 3 and 4) are arranged so that the widest portion of the tapering head 7 can pass through the axial opening 10 when the tapering head 7 is in a predetermined angular orientation. The tip 3 is connected to the housing 1, as follows. The widest portion of the tapering head 7 is aligned with the slots 12 of the axial opening 10 in the transverse partition 4. The head 7 is inserted together with the stem 6 through the axial opening 10 until the tapering inner surface 5 of the tip 3 contacts the tapering surface 2 of the housing 1. Then the tip 3 and the housing 1 are rotated relative to each other (through about 90 ), so that the tapering surfaces 9 and 11 of the tapering head 7 and of the axial opening 10 respectively are facing each other, as shown in Figure 4. The length of the stem 6 is such that when the tip 3 is seated on the housing 1 with the surfaces 5 and 2 in contact, the tapering surfaces 9 and 11 of the tapering head 7 and of the axial opening 10 respectively do not engage each other. These surfaces 9, 11 will normally not engage each other throughout a hole-drilling operation, since contact between the surfaces 5 and 2 is necessary to ensure that an impact is transmitted from the housing 1 to the tip 3. However, when the percussive action device is moved in reverse to retract it from a hole, the tapering surfaces 9, 11 of the tapering head 7 and of the transverse partition 4, respectively, do engage each other, and so the tip 3 is moved with the housing 1 and can be recovered from the drilled hole. The described percussive action device for drilling holes in soil operates, as follows. Prior to drilling a hole, the tapering surface 5 of the tip 3 is seated onto the tapering surface 2 of the housing 1. Depending on the actual operating conditions, the pointed end of the tip 3 is either placed directly onto the soil, or else inserted into a pre-formed hole. Then the percussive-action device is energized, and the hole is drilled. Repeated impacts are transmitted by the housing 1 to the tip 3 which penetrates the soil, moving the housing 1 with it. The peripheral surface of the wall of the housing 1 engages the soil and shapes the wall of the hole. When a hole of the required length has been drilled, the motion of the percussive action device is reversed, whereby the tapering surfaces 9 and 11 of the tapering head 7 and of the transverse partition 4 respectively engage each other, and so allow the tip 3 to be recovered from the hole. Following the withdrawal of the device from the hole, the tip 3 can be easily detached from the housing 1. The above described device can be used most effectively to drill holes in compactible soils. It can also be used in geological surveys for taking soil samples by suitable adaptation of the tip 3. The described connection between the tip and the housing enables the tip to be withdrawn from blind holes and, should it be necessary, to be detached from the housing and replaced by other tools or attachments. The described releasable connection also ensures reliable fixing of the tip on the housing throughout the hole-drilling cycle, and also for rapid and easy detachment of the tip from the housing, when the device has been retracted from the hole. WHAT WE CLAIM IS

1. A percussive action device for forming holes in soil by compaction, the device comprising a housing with a tapering portion and a head portion, and a hollow tip having a pointed front end and a transverse partition therein, the head portion of the housing being arranged to co-operate with the transverse partition to form a releasable coupling between the housing and tip.