GB2131915A

GB2131915A - Releasable coupling

Info

Publication number: GB2131915A
Application number: GB08332790A
Authority: GB
Inventors: Peter Taylor; Roger Bruce Griffin
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-12-15
Filing date: 1983-12-08
Publication date: 1984-06-27
Also published as: GB2131915B; GB8332790D0

Abstract

A releasable coupling comprises a socket member (1), for mounting in a machine tool drive spindle (4) and a spigot (2) received in the socket member (1) which has a driving engagement (6, 260) with the spigot (2). A collar (5) movable between locking and release positions about the socket member (1) has internal cam formation (53') acting on retaining balls (3) which engage an annular groove (23) about the spigot (2) to retain it in the socket (12). Release movement of the collar (5) enables the balls (3) to radially retract for withdrawal of the spigot (2). The collar (5) is spring loaded (8) towards the locking position and a spring loaded ball (9) is arranged to engage a flange (16) of the socket member (1) to hold the collar (5) in the release position, which ball (9) is disengaged by a flange (26) of the spigot (2) on full insertion of the latter in to the socket (12) in order to obtain automatic spring loaded turning of the collar (5) to the locking position where it is retained by spring loaded pawl mechanism (150) releasable by an externally operable plunger (55). <IMAGE>

Description

SPECIFICATION Releasable coupling Theobjectofthisinvention is to provide a coupling which can be quickly released or engaged primarily forthepurpose of interchangeable mounting of rotary toolingeg. in the drive spindle of a machinetool and wherebyaccurate and positive mounting is obtainable as regards axial and co-axial location ofthetooling or for other purposes. Practical advantages in these and other respects will be apparent from the following decription.

Accordingtothis invention a releasable coupling especiallyfortool mounting purposes comprises a socket member; a male member or spigot receivable by the socket ofthe socket member; retaining element or ball means within the socketfor engagementwith co-operati n g formation of the male mem ber or spigot; and an outermemberorcollarmovableaboutthe socket member and on operation arranged to act therethrough on the retaining element or ball means for eitherthrustingthe latter into retentive engage mentwiththe male member or spigot for retention thereof in the socket or conversely for retaining release of said engagement and permitting withdrawal of the male member or spigotfrom the socket.

In a practical example ofthe invention as a quick release coupling for tool mounting purposes the construction and arrangement is as shown in the accompanying drawings in which: Figure 1 is an axial plane section ofthe coupling membersfully engaged with one another, the section being taken on the line l-l of Figure 2, Figure 2 is a cross section taken on the line ll-ll of Figure 1, Figure 3 is an axial plane section of the fully engaged coupling members showing a development, the section being taken on the line Ill-Ill of Figure 4 and Figure 4 is a cross-section taken on the line IV-IV of Figure 3.

The socket member 1 ofthe coupling is shown received by the bore of a drive spindle 4 of a machine tool such as a numerically controlled (N.C. orC.N.C.) machine and is also shown having an external Bridgeporttaperform 74forthis purpose but may be otherwise suitablyformed.

The socket 12 of the member 1 is oftaperform for receiving a male member or spigot 2 of corresponding non-Iockingtaperform and a forward part ofthe socket member 1 is provided with radial bores 13 through itswall each receiving a retaining element shown intheform of a ball 3, the balls 3 releasably engaging an annulargroove 23 in the spigot2.

Provided about thatforward part of the socket member 1 which protrudes beyond the end of the spindle 4 is a ring or coliar 5 internaily formed with inclined cam surfaces 53 which each co-operate with a corresponding ball 3for eitherthrusting the balls 3 in a radial inward direction into engagement with the groove23ofthespigot2orforpermittingtheir retraction therefrom according to the direction of turning movement ofthe collarS about the socket member 1.

Th us the spigot 2 can be quickly inserted intothe socket 12 and retained therein by turning movement of the collar5 in a clockwise direction L as seen, for example, in Figure 2 or just as quickly withdrawn from the socket 12 by turning the collar Sin the opposite direction R. In either case only a short angular extent ofturning movement ofthe coilar 5 is required and the exteriorofthe collar 5 isformedwhereby itcan be readily turned by hand.

For balanced three point retentive engagement with the spigot 2three equi-spaced balls 3 are shown employed buf the numberpf balls may be varied according to requirements, i.e. dependent on the size ofthe coupling and the load which it is required to withstand in use.

For obtaining a positive rotary drive between the socket member 1 and spigot 2 dogged or similar driving engagement of any suitable kind is provided and is shown consisting of studs 6 (one of which is visible in Figure 1) extending from a forward flange 16 of the socket member I and engaged by corresponding radial recesses 260 or bores in a flange 26 about the spigot 2.

A pair of diametrically opposite studs 6 and recesses 260 may be provided in this way or the number may be varied again according to the size and intended load capacityofthecouplingand preferably in an equispaced manner. Asthe spigot 2 is inserted in the socket 12 the recesses 260 are aligned with the studs 6 to provide the driving engagement.

Such driving engagement can be accurately and positively obtained whilst the engagement of the balls 3 with the groove 23 retainsthe spigot 2 firmly seated in the socket 12 for accurate axial location of the socket member 1 and spigot2which is usually further maintained by axial loading under operating conditions.

in orderto releasably maintain the collar Sin the locking position it is preferably spring urged in the appropriate turning direction and this is shown achieved by means of compression springs 8 each accommodated in a curved channel 7 formed by complementary grooves 17,57 about the exterior of the socket member 1 and at the inner periphery ofthe collar 57 in a symmetrical manner, the curved channels 7 so formed being concentrically arranged aboutthe axis of the coupling.

Each spring 8 abuts atone end the corresponding end of the groove 17 inthesocket member 1 and at the other end the corresponding end of the groove 57 in the collar 5. In the refinement shown for obtaining satisfactory abutment a ball 80 is provided at each end of the spring 8. As will be appreciated the grooves 57 ofthecollarSmoveangularlyrelativetothose 17 in the socket member 1 when the collar 5 is turned and some angular end overlap is provided to ensure that necessary radially inward operation ofthe balls 3 can take place when the colllar 5 is fully in the locking position.

For assembly purposes the channels 7 provided by the grooves are closed by annular cover member shown in theform ofaflat ring 70 which is retained in position by a circlip 71 received by the socket member 1. In conjunction with the flange l6the circlip7l and ring 70 serveto axiallyretainthe rotatable collar5 about the socket member 1. The collars is also shown extending axially about the flange 16 at 56 to prevent orminimisethe entry of dirt or swarfinto the mechanism ofthe coupling.

To facilitate withdrawal of the spigot 2 from the socket 12 and more particularly its insertion therein, the collar 5 has an automatically releasable self retaining action when it is turned to the spigot release position to permit retraction of the balls 3 from the annular groove 23. Such releasable retention of the collar 5 against return movement is shown achieved by a spring loaded member or ball 9 carried by the collar 5 and which snaps into a recess or bore 19 in the opposed face of the flange 16 at the leading end of the socket member 1. The action ofthe ball 9 also limits necessary angular release movement ofthe collar 5.

Thus by such retention it is unnecessaryto manually hold the collarS against its angular spring loading by the springs 8 while the spigot 2 is inserted in the socket 12 and in orderto obtain automatic release of such retention a plunger90 in the bore 19 in the flange 16 is depressed bythe flange 26 ofthe spigot2 to push the ball 9 out of engagement with the bore 19. This enables the collar 5 to be turned to the locking position by the springs 8 forth rusting the balls 3 into engagement with the groove 23 of the spigot 2.

As will be appreciated the socket 12 can be kept ready in this wayto receive a spigot 2 but as soon as the spigot 2 is pushedfully home into thesocket 12 retention ofthe collar Sis released for in turn obtaining retention of the spigot 2 in the socket 12 by the action ofthe balls 3.

In a further refinement (not shown) for ensuring balanced spring pressure between the collar 5 and the flange 16, two further spring loaded elements or balls are provided in an equl-spaced mannerto the locking ball 9 shown but which simply bear on the opposed face of the flange 16 since the locking action ofthe one ball 9 is sufficient for retaining the collar Sin the release position.

The shank portion 20 of the spigot 2 may carry or consist of any one of a wide variety oftooling such as, for example, a drill ora milling cutteroratool holder or chuck for use in a quickly interchangeable manner especially in the case of presenttoolsto suit computer controlled operation of the machine. Furthermore, the arrangement does not place any limitation on the form ordiameterofthe shank portion 20 immediately adjacent the flange 26 and which may extend radially beyond the latter.

In a development of the coupling means is provided to positively but releasably prevent release operation ofthe coupling during use, in particular release turning movement of the collar 5, i.e. in the direction of the arrow Rand which otherwise might arise under certain conditions of use involving, for example, exceptional vibration orotherfactors, such as particu larloading on the coupling and/orinertiaforces.

Forthis purpose releasable ratchet locking mechanism is provided and is shown consisting firstly of a blade spring 15 riveted or otherwise secured atone end at 151 to the exterior of the socket member 1 and accommodated in an external side recess 10 bounded bythe collar S, i.e. in the general plane ofthe balls 3.

The otherorfree end 150 ofthe blade spring 15 acts as a pawl in engaging ratchet teeth 50 locally formed at an appropriate location on the inner periphery of the collar 5.

As the collar 5 isturned in the locking direction Lto th rust the balls 3 into retentive engagement with the groove 23 ofthe spigot 2,thefree end 150 ofthe blade spring IS rides over one or more oftheteeth 50 into abutment with one of them for positively preventing return or release rotation R ofthe collar 5.

However, when it is required to effect release turning movement of the collar 5 provision is included for disengaging or lifting the end 150 of the blade spring 15 from the ratchetteeth 50 and is shown consisting of a plunger 55 operating in a radial bore 51 in the collar 5 which bore 51 breaks through the inner wall of the collar 5 atthe location of the ratchet teeth 50.

As the exterior ofthe collar S is grasped by the hand for release turning operation,the head 550 of the plunger 55 is depressed to lift the blade spring end 150 from the ratchet teeth 50 and so permit releasing turning of the collar 5. (Note the ratchet teeth 50 are on the inner periphery ofthecollarS, i.e. they are not on the inner end of the plunger 55).

Forassemblypurposesthe plunger 55 is of two part construction in which a shank 551 of the head 550 is positively secured in the plunger body 555, the latter havingaflange552atitsinnerendengaging acounter bore 512 of the bore 51 for captive retention of the plunger 55 in the collar 5 for necessary radial movement. The blade spring 1 5 also serves to thrust the plunger 55 outwardly so that its head 550 projects from the exterior of the collar Sforthumb pressure operation.

A modified form of cam surface 53' is shown together with a part spherical or curved recess 530 for accommodating the corresponding ball 3 in the release position.

Only one ofthree compression springs 8 and associated end balls 80 are indicated in Figure 4 in the interests of clarity.

The quick release action and rapid mounting obtained by means ofthe coupling represents a considerable saving in tool changing time compared with the known procedure of retaining a male member or spigot in a socket member by a ring nut, which latter requires to be firmly tightened for retention of the members and unscrewed for their release.

Claims

1. A releasable coupling especiallyfortool mounting purposes comprising a socket member; a male member or spigot receivable by the socket of the socket member; retaining element or ball means within the socket for engagement with co-operating formation of the male member or spigot; and an outer member or collar movable about the socket member and on operation arranged to acttherethrough on the retaining element or ball means for either thrusting the latter into retentive engagement with the male member orspigotfor retention thereof in the socket or converselyfor obtaining release of said engagement and permitting withdrawal of the male member or spigot from the socket.

2. A releasable coupling according to Claim 1 wherein the socket member is arranged to have a releasable rotary driving engagement with the male memberorspigot.

3. A releasable coupling according to Claim 2 wherein the socket member has a releasable projection and recess engagement with radial flange or similarformationofthemalememberorspigotonfull insertion of the latter into the socket member.

4. A releasable coupling according to Claim 1,2 or 3 wherein the retaining element or ball means is engageable with an annular groove about the male memberorspigot.

5. A releasable coupling according to any of the preceding claims wherein the inner periphery of the outer member or collar is provided with cam or like formation which co-acts with the retaining element or ball means for moving the latter radially in radial bore means through the socket member for thrusting said retaining element or ball means into retentive engagementwith the co-operating formation or groove ofthe male memberorspigotor permitting release ofthe retaining element or ball means therefrom on appropriate movement ofthe outer member or collar about the socket member.

6. A releasable coupling according to any ofthe preceding claims wherein the outer member or collar and the socket member are spring urged for relative movement in a direction for obtaining retentive engagement of the retaining element or ball means with the male member or spigot

7. A releasable coupling according to Claim 6 wherein the outer member or collar and the socket member are spring urged by compression spring means acting between them and located in cooperating grooving in the inner peripheryofthe outer memberorcollarand in an outer peripheral partofthe socket member.

8. A releasable coupling according to any ofthe preceding claims wherein releasable retaining means is provided acting betweentheoutermemberorcollar andthe socket member for releasably retaining the outer member or collar and socket member in a relative position wherebythe retaining element or ball means is ableto move to a position for disengagementfrom the male member or spigot.

9. A releasable coupling according to Claim 8 wherein the releasable retaining means is adapted to be actuated to the release position on full insertion of the male member or spigot into the socket ofthe socket memberto permit movement of the outer member or collar relative to the socket member for thrusting the retaining element or ball means into retentive engagement with the male member or spigot.

10. A releasable coupling according to Claim 6 or 8 with Claim 9 wherein said release actuation ofthe retaining means permits spring loaded movement of the outer member or collar relative to the socket memberforthrusting the retaining element or ball means into retentive engagement with the male member or spigot in an automatic manner.

11. A releasable coupling according to any of the preceding claims wherein releasable retaining means is provided acting between the socket member and the outer member or collar for releasably retaining the latter and the socket member in a relative position whereby the retaining element or ball means is maintained in engagement with the male member or spigot.

12. A releasable coupling according to Claim 11 wherein the releasable retaining means consists of spring loaded pawl and ratchet means acting between an outer peripheral part ofthe socket member and an inner peripheral partoftheoutermemberorcollarand operable for release from the exterior of the latter.

13. A releasable coupling according to Claim 12 wherein the retaining means comprises a spring loaded pawl carried by an outer peripheral part of the socket member and arrangedto engage ratchet tooth formation on an inner peripheral part of the outer memberorcollar, and a plunger carried bythe latter and extending thereth rough for exterior operation in orderto liftthe pawl from engagementfrom the ratchet tooth formation when release ofthe retaining means is required, i.e. on movement of the outer member or collarto permit release retraction of the retaining element or ball means.

14. A releasable coupling according to Claim 12 or 13 wherein the spring loaded pawl consists of a blade spring secured to the outer peripheral part ofthe socket member, a free end ofthe blade spring acting as a pawl for engaging the ratchet tooth formation on the inner peripheral part of the outer member or collar

15. A releasable coupling according to any of the preceding claimswherein the outer member or collar extends about a forward part or flange of the socket member in orderto preventorminimiseentryofdirt orswarfintothe coupling.

16. Areleasablecoupling especiallyfortool mounting purposes when substantially as herein described with reference to Figures 1 and 2 or Figures 3 and 4 of the accompanying drawings.