GB2165794A

GB2165794A - Percussion implement

Info

Publication number: GB2165794A
Application number: GB8525134A
Authority: GB
Inventors: Helmut Schmied
Original assignee: Licentia Patent Verwaltungs GmbH
Current assignee: Licentia Patent Verwaltungs GmbH
Priority date: 1984-10-18
Filing date: 1985-10-11
Publication date: 1986-04-23
Also published as: GB8525134D0; DE3438208A1; DE3438208C2; CH668028A5; CN85106839A; CN1004476B; GB2165794B

Abstract

A hand-held percussion implement has a pneumatic (air-cushion) drive member 1 vibrated via a radially-extending tumble member 6; rotation of the drive member 1 is prevented by a projection 13 of the tumble member 6 being embraced by a pair of parallel pin elements 14, 15. The pin elements are mounted through bores 18 (19, Figure 2 not shown) in an extension 17 of the drive member 1 into blind bores 18' (19') in the rear wall 16 of the drive member 1, and are located immediately above a bearing sleeve 4 for a round head portion 5 of member 6. <IMAGE>

Description

SPECIFICATION Percussion implement The present invention relates to a percussion implement and more particularly to a hand-held hammer drilling tool such as a drifter. The drifter may have a percussion mechanism which contains a piston-like drive member which is guided in a cylindrical guide tube and which, by pneumatic means, sets in reciprocating motion a percussion member, which is freely movable axially, which percussion member delivers its energy in the form of axial blows to a tool guided in the drifter.The drive member may be set in oscillatory motion by an electric motor through a tumble member which comprises a push rod extending radially and provided with a rounded head portion, the rounded head portion being mounted in a rear extension of the piston-like drive member, the push rod continuing radially beyond the head portion and this continuation being prevented from tangential movement in the rear extension of the drive member.

In order to secure the drive member against rotation, it has already been proposed to guide the continuation of the push rod in a plate which is provided with a slot and which is disposed in a rear extension of the drive member (De-PS 33 35 305).

Such a retaining plate, including its mounting, is, on the one hand, expensive and, on the other hand, has proved inadequate in so far as there is a risk of the plate becoming detached during operation and hence of destruction of the drive piston.

The present invention seeks to provide a means of securing the drive member against rotation which is simple in construction and easy to mount and with which the risk of detachment is eliminated.

According to the present invention there is provided a percussion implement having a drive member which pneumatically causes reciprocation of an axially-movable percussion member for delivering axial blows to a tool inserted in the front of the implement, the drive member being vibrated by a tumble member having a round head portion and a radially extending push rod, the round head portion being mounted in a rearward extension of the drive member and the tumble member having a radially extending portion on the side of the head portion remote from the push rod, wherein rotary movement of the drive member is prevented by two parallel spaced pin elements which embrace said radially extending portion, the pin elements being held in the rear wall of the drive member and the end wall of the rearward extension.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 shows a partial section through a drive member actuated by a tumble drive; Figure 2 shows a plan view of the drive member; and Figure 3 shows a view on the section A - B through Figure 2.

As can be seen from Figure 1, the drive member 1, is constructed in the form of a hollow piston and with an air cushion reciprocates the percussion member 2, which is freely movable axially. The drive member includes at its rear end an extension 3 in which a bearing sleeve or ring 4 is inserted.

Guided in the bearing sleeve 4 is the spherically rounded head 5 of a push rod 6 which, extending radially, is fitted to the outer ring of a ball bearing arrangement 8. The ball bearing arrangement is disposed inclined at an angle CC to the axis 9 of an intermediate shaft 10 which carries and drives a shaft member 12 provided with a suitably inclined seat 11 for the ball bearing 8.

The continuation 13 of the push rod, projecting beyond the rounded head portion 5, id guided betwenn two dowel pins 14, 15 which are disposed spaced apart and extend parallel to one another and which are held or anchored, on the one hand, in the rear wall 16 of the drive member and, on the other hand, in the end wall 17 of the rear extension 3 of the drive member.

The two dowel pins 14 and 15 are inserted in two through bores 18, 19 in the end wall 17 of the extension 3 and are pressed forwards until they come into engagement with the blind bores 18', 19' in the wall 16 of the drive member. In this connection see also Figures 2 and 3.

With such securing means, a rotary movement of the drive member in the circumferential direction is prevented. The torque acting on the drive member results from a component of force acting on the push rod 6 in the rotational direction and the displacement travel of the centre of the head portion 5. The pins 14, 15 may be in the form of clamping sleeves or cylindrical pins.

1. A percussion implement having a drive member which pneumatically causes reciprocation of an axially-movable percussion member for delivering axial blows to a tool inserted in the front of the implement, the drive member being vibrated by a tumble member having a round head portion and a radially extending push rod, the round head portion being mounted in a rearward extension of the drive member and the tumble member having a radially extending portion on the side of the head portion from the push rod, wherein rotary mo9- ment of the drive member is prevented by two parallel spaced pin elements which embrace said radially extending portion, the pin elements each being held in the rear wall of the drive member and the end wall of the rearward extension.

2. An implement as claimed in Claim 1, wherein the pin elements are in the form of clamping sleeves.

3. An implement as claimed in Claim 1, wherein the pin elements are in the form of cylindrical pins.

4. An implement as claimed in any preceding claim, wherein the pin elements are located immediately above an end face of a bearing sleeve in

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Percussion implement The present invention relates to a percussion implement and more particularly to a hand-held hammer drilling tool such as a drifter. The drifter may have a percussion mechanism which contains a piston-like drive member which is guided in a cylindrical guide tube and which, by pneumatic means, sets in reciprocating motion a percussion member, which is freely movable axially, which percussion member delivers its energy in the form of axial blows to a tool guided in the drifter.The drive member may be set in oscillatory motion by an electric motor through a tumble member which comprises a push rod extending radially and provided with a rounded head portion, the rounded head portion being mounted in a rear extension of the piston-like drive member, the push rod continuing radially beyond the head portion and this continuation being prevented from tangential movement in the rear extension of the drive member. In order to secure the drive member against rotation, it has already been proposed to guide the continuation of the push rod in a plate which is provided with a slot and which is disposed in a rear extension of the drive member (De-PS 33 35 305). Such a retaining plate, including its mounting, is, on the one hand, expensive and, on the other hand, has proved inadequate in so far as there is a risk of the plate becoming detached during operation and hence of destruction of the drive piston. The present invention seeks to provide a means of securing the drive member against rotation which is simple in construction and easy to mount and with which the risk of detachment is eliminated. According to the present invention there is provided a percussion implement having a drive member which pneumatically causes reciprocation of an axially-movable percussion member for delivering axial blows to a tool inserted in the front of the implement, the drive member being vibrated by a tumble member having a round head portion and a radially extending push rod, the round head portion being mounted in a rearward extension of the drive member and the tumble member having a radially extending portion on the side of the head portion remote from the push rod, wherein rotary movement of the drive member is prevented by two parallel spaced pin elements which embrace said radially extending portion, the pin elements being held in the rear wall of the drive member and the end wall of the rearward extension. A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 shows a partial section through a drive member actuated by a tumble drive; Figure 2 shows a plan view of the drive member; and Figure 3 shows a view on the section A - B through Figure 2. As can be seen from Figure 1, the drive member 1, is constructed in the form of a hollow piston and with an air cushion reciprocates the percussion member 2, which is freely movable axially. The drive member includes at its rear end an extension 3 in which a bearing sleeve or ring 4 is inserted. Guided in the bearing sleeve 4 is the spherically rounded head 5 of a push rod 6 which, extending radially, is fitted to the outer ring of a ball bearing arrangement 8. The ball bearing arrangement is disposed inclined at an angle CC to the axis 9 of an intermediate shaft 10 which carries and drives a shaft member 12 provided with a suitably inclined seat 11 for the ball bearing 8. The continuation 13 of the push rod, projecting beyond the rounded head portion 5, id guided betwenn two dowel pins 14, 15 which are disposed spaced apart and extend parallel to one another and which are held or anchored, on the one hand, in the rear wall 16 of the drive member and, on the other hand, in the end wall 17 of the rear extension 3 of the drive member. The two dowel pins 14 and 15 are inserted in two through bores 18, 19 in the end wall 17 of the extension 3 and are pressed forwards until they come into engagement with the blind bores 18', 19' in the wall 16 of the drive member. In this connection see also Figures 2 and 3. With such securing means, a rotary movement of the drive member in the circumferential direction is prevented. The torque acting on the drive member results from a component of force acting on the push rod 6 in the rotational direction and the displacement travel of the centre of the head portion 5. The pins 14, 15 may be in the form of clamping sleeves or cylindrical pins. CLAIMS

4. An implement as claimed in any preceding claim, wherein the pin elements are located immediately above an end face of a bearing sleeve in the rearward extension for the round head portion of the tumble member.

5. An implement as claimed in any preceding claim, wherein the drive member is located in a cylindrical guide tube.

6. An implement as claimed in any preceding claim, wherein the drive member is vibrated via the tumble member by an electric motor.

7. A hand-held implement according to any preceding claim.

8. A percussion implement substantially as herein described with reference to the accompanying drawings.