GB2099904A

GB2099904A - Spigot and socket assembly

Info

Publication number: GB2099904A
Application number: GB8112300A
Authority: GB
Original assignee: Lattimer E R Ltd
Current assignee: Lattimer E R Ltd
Priority date: 1981-04-21
Filing date: 1981-04-21
Publication date: 1982-12-15
Also published as: GB2099904B

Abstract

To enable frusto-conical spigot 19 to be retained positively in complementary socket 11 with zero eccentricity, and readily to be ejected from said socket 11, radial threaded holes 12 and 14 accommodate respectively a locking screw 16 which when screwed in, engages a locking abutments surface 23 provided in notch 20 to force the spigot 19 inwards of the socket 11, and an ejector screw which when screwed in engages a corresponding ejector abutment surface 24 in notch 21 to eject the spigot 19. The spigot 19 may be the shank of a tool, and the socket 11 may be in a tool holder 10 as part of a machine tool. <IMAGE>

Description

SPECIFICATION Spigot and socket assembly This invention concerns spigot and socket assemblies.

Spigot and socket connections or couplings are provided in multitudiuous engineering environments. For instance, it is quite common to fit a working tool, such as a cutting tool, into an appropriate holder in a machine by a spigot in the form of a shank of the tool fitting into and being retained in a complementary socket-opening in a socket-type holder.

In one known type of such connections or couplings, the shank is parallel and the socket opening is correspondingly parallel incorporating, for example, a contracting bush, collet or the like which serves to grip the inserted shank.

In another known type, with which the present invention is concerned, the shank is tapered and the socket-opening in the holder is complementarily tapered. Various provisions may then be made for ensuring retention of the shank in the holder so that both components will rotate in unison. For instance the taper angle may be so chosen that a so-called "self-holding taper" is achieved. In some instances, an anti-torsion device, ensuring co-rotation ofthe two components, is provided between the two components, this being for example tangs or a key/keyway assembly or a drawbar arrangement.

Tapered arrangements as just discussed have the advantage that they enable zero concentricity to be achieved between the axes of the socket and the shank and permit maximum rigidity to be obtained therebetween. However, in practice means provided in the known arrangements for achieving such retention and permitting subsequent extraction of the shank from the holder have generally been cumbersome, inconvenient and time-consuming in use, and may be detrimental to the tool and/or the machine spindle on which the tool holder is mounted for instance by requiring complete removal ofthe holder and tool from the machine.In such instances, the mere removal and replacement of the tool holder can be detrimental to and cause wear on the machine, especially if care is not taken to effect meticulous cleaning and to ensure that there are no burrs or the like on the holder or the tool carried thereby, which might damage the spindle.

The machine spindle often represents a major capital component of such a machine and consequently replacement, after damage thereof, would represent a capital expense which should be avoided if at all possible. It is an object ofthe present invention to provide a spigot and socket assembly, suitable for use in machines and other engineering environments as above discussed wherein the aboveexplained disadvantages are obviated, the arrangement providing for a very simple retention of the spigot in the socket and also for simple extraction thereof from the socket, so that complete removal of the socket member from its spindle, and possible damage to the latter, are reliably obviated.

With this object in view, the present invention provides a spigot and socket assembly, for example a tool shank and tool holder in a machine, characterised in that it comprises a socket member wherein is a conicalor frusto-conical socket as well as a pair of threaded apertures, for receiving respectively a locking screw and an ejector screw and is disposed in a plane or respective planes intersected substantially perpendicularly by the axes of the socket, and a tapered spigot complementary to and fitting into the socket, said spigot being formed with a locking notch or recess and an ejector notch or recess disposed to register respectively with the locking screw aperture and the ejector screw aperture, the locking notch or recess having an abutment locking face with which the locking screw will cooperate to urge the spigot inwards of the socket and the ejector notch or recess having an ejecting abutment face with which the ejector screw will cooperate to urge the spigot outwards of the socket.

The invention will be described further, by way of example, with reference to the accompanying drawing, in which: Fig. 1 is a fragmentary exploded view illustrating a first embodiment of the spigot and socket assembly ofthe invention; and Fig. 2 is a view comparable with Fig. 1 but illustrating a second embodiment ofthe spigot and socket assembly of the invention.

The spigot and socket assembly illustrated in Fig. 1 comprises a socket member 10 which is, for example, a rotary tool holder of a machine tool of which the rest is not shown in the drawing. Formed axially of the socket member 10 is a frusto-conical socket 11. Also provided in said member 10 is a substantially radially-disposed threaded locking screw aperture 12, this being positioned relatively close to front face 13 of the member 10 as well as a correspondingly radially-disposed threaded ejector screw aperture 14, this being positioned relatively further away from the front face 13. A threaded grub-type locking screw 16 engages in the aperture 12, and a similar ejector screw 17 engages in the aperture 14.

A spigot 18 of the assembly has a tapered stem 19 complementary to the socket 11. This spigot 18 may, for instance, be the shank of a tool which fits into the tool holder 10. Formed in the stem 19 are a locking notch or recess 20 and an ejector notch or recess 21, and it will readily be understood that when the stem has been engaged into the socket 11 the notch 20 registers with the aperture 12 and the notch 21 similarly registers with the aperture 14. Each of the notches or recesses 20,21 is formed, e.g. by milling or other suitable machining operation, to have a respective abutment surface 23, 24, which is inclined relative to a plane to which axis 25 of the stem 19 is perpendicular.In the case ofthe locking notch or recess 20, the inclined abutment surface 23 is at the side towards the smaller diameter end of the stem 19 whereas in the case of the eiector notch or recess 21 The drawing(s) originally filed were informal and the print here reproduced is taken from a later filed formal copy.

the inclined abutment surface 24 is at the side towards the larger diameter end of the stem 19.

The manner of fitting the spigot 18 to the socket member 10, and its removal therefrom, will readily be understood from the foregoing description. Of course, the locking screw 16 and ejector screw 16 and 17 will normally be accomodated in their respective apertures 12 and 13, which intersect with the socket 11 from diametrically opposite locations, but without projecting into the socket 11.The stem 19 is inserted into the socket 11 with the notches or recesses 20,21 registering with the respective apertures 12,14, and is locked in place by tightening the locking screw 16 inwards until its inner end abuts against the abutment surface 23 whereupon further tightening of said screw 16 ensures that the stem 19 is forced fully home into the socket 11 and is locked in place without their being any risk of eccentricity or of deterioration ofthe mating surfaces ofthe socket member 10 and the spigot 18.

When subsequently it is desired to remove the spigot 18 from the socket 11, firstly the locking screw 16 is released by screwing it outwards until its inner end no longer projects into the socket 11. Then, the ejector screw 17 is screwed inwards. Upon abutting its abutment surface 24the screw 17 displaces the stem 19 sufficiently outwardly of the socket 11 to release the spigot 18 which can then be removed from the tool holder 10.

The embodiment illustrated in Fig. 2 is very similar to that just described and similar reference numerals have been allocated to parts which are similarto those already described. However, in this instance the spigot 18 comprises a relatively large shank with which the frusto-conical stem 19 connects by an abrupt shoulder 40, and this spigot may form a rotary part of a machine tool, or other mechanical contrivance.

It will readily be understood that in this embodiment the spigot 18 can be locked in place by means of the locking screw 16 and can be ejected by use of the ejector screw 17 in exactly the same way as in the embodiment of Fig. 1.

The invention is not confined to the precise details of the foregoing examples and variations may be made thereto. For instance, although the invention has been described with particular reference to machine parts it can be employed in virtually any environment involving a conical or frusto-conical spigot fitting into a complementary socket. Thus it could be employed, for example, where complementary parts of hand tools are required to fit together, where a pulley, wheel or other component is required to fit onto a frusto-conical part of a shaft, in the connecting together of pipe ends and so on. The positions of the locking and ejector apertures do not have to be diametrically opposed as shown and they can be in any practical locations, which do not have to be radial but can be chordal relative to the socket.

Other variations are possible.

Claims

1. A spigot and socket assembly, for example a tool shank and tool holder in a machine, characterised in that it comprises a socket member wherein is a conical or frusto-conical socket as well as a pair of threaded apertures, for receiving respectively a locking screw and an ejector screw disposed in a plane or respective planes intersected substantially perpendicularly by the axis of the socket, and a tapered spigot complementary to and fitting into the socket, said spigot being formed with a locking notch or recess and an ejector notch or recess disposed to register respectively with the locking screw aperture and the ejector screw aperture, the locking notch or recess having a locking abutment face with which the locking screw will cooperate to urge the spigot inwards of the socket and the ejector notch or recess having an ejecting abutment face with which the ejector screw will cooperate to urge the spigot outwards of the socket

2. An assembly as claimed in claim 1 wherein the threaded apertures intersect the socket from diametrically opposed locations.

3. An assembly as claimed in claim 1 or 2 in which the locking screw aperture is disposed relatively close to the front face of the socket member and the ejector screw aperture is disposed relatively further away from said front face.

4. An assembly as claimed in claim 1,2 or 3 in which the notches or recesses are chordally disposed relative to the spigot.

5. A spigot and socket assembly substantially as hereinbefore described with reference to and as illustrated in Fig. 1 or Fig. 2 of the accompanying drawing.