GB1568044A - Floating reamer - Google Patents

Abstract

With its rear hollow-cylindrical end, the cutter head (2) overlaps the front spigot-shaped end (11) of the shank (1), into which a guide sleeve (5) is inserted which accommodates a pin (6) extended into the wall of the cutter head. In this arrangement, the cutter head bears with its rear, annular end face (22) against the annular shoulder (12) of the shank. Tilting of the cutter head can thereby be avoided. <IMAGE>

Description

(54) FLOATING REAMER (71) We, MAPAL Fabrik fur Prazisionswerk-zeuge Dr. Kress KG, a German Company of Obere Bahnstrasse 13, D-7080 Aalen, Germany, 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 invention relates to a floating reamer having a head for carrying the cutters that is transversely displaceable on the reamer shank.

In known floating reamers (DT-PS 664 304), the cutter-head has an attachment of hammer-head shaper which is guided between fillets on the shank of the reamer.

Also known are floating reamers (DT-OS 24 36 501) wherein is provided a special cutter holder which is guided in a radial opening in the cutter-head.

A disadvantage associated with such floating reamers is that the slide faces are exposed to the risk of contamination which adversely affects the ease with which the floating movement takes place.

Since the force to which the cutter-head is subjected during reaming is applied to the forward zone of the head, this can lead to tilting of the cutter-head on the slide faces in known floating reamers. The cutter-head therefore does not float along the axis of the work-piece, and this leads to bores that do not fall within the required tolerances.

It is desirable to guide the cutter head on the shank of the reamer in such a way that the guide faces are not exposed to the risk of contamination or penetration by fine swarf occurring during machining. and that the cutter-head is precisely guided at right angles to the axis of the shank. The present invention seeks to provide an improved floating reamer.

According to the invention there is provided a floating reamer comprising a shank and a cutter-head which is displaceable to a limited extent transversely of a central longitudinal axis of the shank; the shank having a shoulder, a reduced diameter spigot extending beyond the shoulder at one end of the shank, a transverse bore in the spigot, and a guide sleeve in the transverse bore; the cutter-head having a cylindrical socket in one end thereof into which the spigot extends, a pin fitted in the cutterhead to extend transversely thereof across the socket. the pin passing through the guide sleeve in the shank thereby connecting the cutter-head to the shank, and an annular end surface extending around the socket and bearing against the shoulder on the shank. clearance being provided between the cutter-head and the spigot in the socket wherebv the cutter-head is transversely displacable.

The amount of the floating play is conveniently determined by the difference between the outside diameter of the reduced diameter spigot and the inside diameter of the socket in the cutter-head.

The floating movement of the cutter-head can be cushioned in a simple manner by letting a ring of resilient material into one of the two clearance-defining cylindrical faces of the spigot or of the socket respectively.

An embodiment of the invention is illustrated diagrammatically in the accompanying drawings. in which: Figure l is a side view. partly in section, of the end of a floating reamer in accordance with the invention; and Figure 2 is a section through the cutterhead in the zone of the guide means, on the line 2-2 of Figure 1.

The reamer consists of the shank 1 and a cutter-head 2 which is displaceable radially of the shank. The cutter-head has two cutter-plates 3 at its periphery. only one of these cutter-plates being shown in Figure 1.

The cutter-plates are inserted in slots and are pressed by a clamping element 4 against the rear flank of the slots. In the forward end 11 of the shank that is formed as a smaller diameter spigot is inserted in a transverse bore a guide sleeve 5 which is in the form of a ball cage and accommodates a pin 6, which is inserted into bores formed in the cutter-head which has a hollow cylindrical socket in its rearward zone 21. The rearward annular end-face 22 of this hollow cylindrical portion 21 lies completely flat against the annular shoulder 12 of the shank 1. Since these faces which slide one over the other are relatively small, the sliding resistance between the cutter-head and the shank is considerably reduced as compared with that of known floating reamers. In this way, tilting of the reamer-head is prevented so that this head can move into a position in which it floats precisely along the axis of the workpiece and thus forms a bore of precise dimensions.

WHAT WE CLAIM IS: 1. A floating reamer comprising a shank and a cutter-head which is displaceable to a limited extent transversely of a central lonitudinal axis of the shank; the shank having a shoulder, a reduced diameter spigot extending beyond the shoulder at one end of the shank, a transverse bore in the spigot, and a guide sleeve in the transverse bore; the cutter-head having a cylindrical socket in one end thereof into which the spigot extends, a pin fitted in the cutterhead to exend transversely thereof across the socket, the pin passing through the guide sleeve in the shank therebv connecting the cutter-head to the shank, and an annular end surface extending around the socket and bearing against the shoulder on the shank; clearance being provided between the cutter-head and the spigot in the socket whereby the cutter-head is transversely displaceable.

2. A floating reamer according to Claim 1, wherein the extent of the floating displacement is determined by the width of the annular gap between the spigot and the socket cutter-head.

3. A floating reamer according to either of the preceding claims wherein a ring of resilient material is let into one of the two cylindrical faces delimiting the annular gap between the spigot and the socket, for the purpose of cushioning the floating movement.

4. A floating reamer as claimed in anv one of the preceding claims wherein the guide sleeve is formed as a ball cage.

5. A floating reamer substantially as hereinbefore described with reference to the accompanying drawings.

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

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. are pressed by a clamping element 4 against the rear flank of the slots. In the forward end 11 of the shank that is formed as a smaller diameter spigot is inserted in a transverse bore a guide sleeve 5 which is in the form of a ball cage and accommodates a pin 6, which is inserted into bores formed in the cutter-head which has a hollow cylindrical socket in its rearward zone 21. The rearward annular end-face 22 of this hollow cylindrical portion 21 lies completely flat against the annular shoulder 12 of the shank 1. Since these faces which slide one over the other are relatively small, the sliding resistance between the cutter-head and the shank is considerably reduced as compared with that of known floating reamers. In this way, tilting of the reamer-head is prevented so that this head can move into a position in which it floats precisely along the axis of the workpiece and thus forms a bore of precise dimensions. WHAT WE CLAIM IS:

1. A floating reamer comprising a shank and a cutter-head which is displaceable to a limited extent transversely of a central lonitudinal axis of the shank; the shank having a shoulder, a reduced diameter spigot extending beyond the shoulder at one end of the shank, a transverse bore in the spigot, and a guide sleeve in the transverse bore; the cutter-head having a cylindrical socket in one end thereof into which the spigot extends, a pin fitted in the cutterhead to exend transversely thereof across the socket, the pin passing through the guide sleeve in the shank therebv connecting the cutter-head to the shank, and an annular end surface extending around the socket and bearing against the shoulder on the shank; clearance being provided between the cutter-head and the spigot in the socket whereby the cutter-head is transversely displaceable.

2. A floating reamer according to Claim 1, wherein the extent of the floating displacement is determined by the width of the annular gap between the spigot and the socket cutter-head.

3. A floating reamer according to either of the preceding claims wherein a ring of resilient material is let into one of the two cylindrical faces delimiting the annular gap between the spigot and the socket, for the purpose of cushioning the floating movement.

4. A floating reamer as claimed in anv one of the preceding claims wherein the guide sleeve is formed as a ball cage.

5. A floating reamer substantially as hereinbefore described with reference to the accompanying drawings.