Clamping device for a cutting insert
A metal cutting tool assembly comprising a rigid holder blade, an insert receiving slot formed in a leading end of the holder blade and defined between a resiliently displaceable clamping jaw formed integrally with the holder blade and rigid base jaw forming part of the holder blade, spaced apart displacement and supporting surfaces respectively formed in or on the clamping jaw and the holder, and a slot opening key, a pair of spaced apart projecting prongs of the key with adapted to engage the surfaces. At least one of the prongs is displaceable with respect to the holder blade so as resiliently to displace the clamping jaw outwardly with respect to the base jaw into an opening position for insertion or removal of an insert.
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This is a continuation of application Ser. No. 08/342,277, filed Nov. 18, 1994, now U.S. Pat. No. 5,697,271.
FIELD OF THE INVENTIONThis invention relates to metal cutting tool assemblies of the kind wherein an exchangeable cutting insert is releasably retained in an insert retaining slot formed in a holder blade. The invention relates particularly to such a cutting tool assembly wherein the insert is retainably clamped within the retaining slot between a resiliently displaceable clamping jaw and a rigid base jaw without the use of additional mechanical clamping means such as clamping screws or the like.
BACKGROUND OF THE INVENTIONOne known form of cutting tool assembly of the kind to which the invention relates involves the so-called “wedge clamping” of the insert in the insert retaining slot. Here, the insert, having a single cutting edge, is provided with a wedge-shaped body which forcibly inserted and is retained within a correspondingly wedge-shaped retaining slot, the actual clamping of the insert within the slot being effected by the resilient outward displacement of the clamping jaw as a result of the forced insertion of the insert into the slot. With this type of cutting tool assembly, the resilient displacement of the jaw is effected by the insertion of the insert into the slot, but when it is desired to remove the insert, special means have to be provided for mechanically ejecting the insert from the slot, these means involving the direct exertion of an ejection pressure on the insert. It will be understood that both the insertion and removal of the insert is accompanied by significant friction with consequent wear on the blade jaws which are, in general, of a much softer material than that of the insert.
Alternatively, it is known (GB 1379637) to introduce into and clamp an insert within an insert retaining slot by first of all mechanically displacing outwardly a resiliently clamping jaw, introducing the insert into the slot and then allowing the jaw to spring back on to the insert in a clamping position. When it is desired to remove the insert from the slot, the clamping jaw is again displaced outwardly, allowing for the removal of the insert. The outward displacement of the jaw is effected using a mechanical key which is displaced in frictional contact with the inside of the clamping jaw, thereby leading to frictional wear of the jaw and/or the key.
BRIEF SUMMARY OF THE INVENTIONIt is an object of the present invention to provide a new and improved metal cutting tool assembly in which the above-referred-to disadvantages are substantially reduced or overcome.
According to the present invention, there is provided a metal cutting tool assembly comprising a rigid holder blade;
-
- an insert receiving slot formed in a leading end of the holder blade and defined between a resiliently displaceable clamping jaw formed integrally with said holder blade and rigid base jaw forming part of the holder blade;
- spaced apart displacement and supporting surfaces respectively formed in or on said clamping jaw and said holder; and
- a slot opening key, a pair of spaced apart projecting prongs of said key adapted to engage said surfaces, at least one of said prongs being displaceable with respect to said holder blade so as resiliently to displace said clamping jaw outwardly with respect to said base jaw into an opening position for insertion or removal of an insert.
Preferably, there is formed in the holder blade an extension slot communicating with said insert receiving slot and extending rearwardly thereof. There can be formed in the clamping jaw forwardly of said extension slot a clamping jaw aperture, said displacement surface being constituted by a rim of said clamping jaw aperture.
In accordance with one preferred embodiment of the present invention, the supporting surface is formed on an upper surface of said clamping jaw adjacent said extension slot, one of said prongs being adapted to project into said clamping jaw aperture whilst the other of said prongs bears on said supporting surface, whereby a levering displacement of said one prong with respect to the other prong results in the outward displacement of said clamping jaw.
Alternatively, and in accordance with another preferred embodiment of the present invention, the supporting surface is formed in said base jaw, said supporting surface being constituted by a rim of said base jaw aperture and wherein said opening key is provided with means for displacing said prongs apart whereby, with said prongs projecting respectively into said clamping jaw and base jaw apertures, displacement apart of said prongs results in said outward displacement of said clamping jaw.
Thus, with a cutting tool assembly in accordance with the present invention, displacement of the clamping jaw, whether effected by a levering action or by way of a direct, linearly directed displacement, is not accompanied by any direct contact, either with the insert or with the inner surface of the clamping jaw, and in this way damage thereto is avoided or minimized. Furthermore, introduction into and removal of the insert from the slot is not accompanied by any frictional resistance by the opposite jaw surfaces and there is therefore avoided frictional wear of these surfaces leading to an extended life of the holder blade as a whole.
For a better understanding of the present invention and to show how the same may be put into practice by way of example, reference will now be made to the accompanying drawings, in which:
As seen in
As can be seen in dotted lines in
In order to allow for the introduction of an insert 7 (shown in
As can furthermore be seen in
There is formed in the clamping jaw 3, forwardly of the neck portion 5, a throughgoing aperture 14, whilst there is formed in the base jaw 4, adjacent a front edge thereof, a throughgoing aperture 15.
Reference will now be made to
Located between the legs 23a, 23b and bearing against them is a wedge-like spacer 25 having a throughgoing threaded bore 26 through which extends a screw 27, an upper end of which remote from the spacer 25 is coupled to a turning handle 28.
Rotation of the turning handle 28 in the direction of the arrow 29 results in an inwardly-directed displacement of the spacer 25, thereby giving rise to an outwardly-directed displacement of the legs 23a, 23b and a consequent outwardly-directed displacement of the prongs 24a, 24b in the direction of the arrows 30a, 30b.
If now, and prior to the rotation of the handle 28 so as to cause the outward displacement of the prongs 24a, 24b, the latter are inserted in the apertures 15, 14 and rotation of the handle 28 takes place in the direction of the arrow 29, it will be readily seen that there occurs an outwardly-directed displacement of the clamping jaw 3. As a consequence, the clamping jaw 3 effectively pivots about its narrow neck portion 5, thereby increasing the spacing between the clamping jaw 3 and the base jaw 4 and allowing for the introduction or removal of the insert 7. Rotation of the handle 28 in the opposite direction allows for the clamping jaw 3 to return into a clamped position, thereby clampingly retaining the insert in position.
If now, as before, the prongs 34a, 34b are positioned within the apertures 15, 14, rotation of the handle in one sense gives rise to an outwardly-directed displacement of the clamping jaw, allowing for the insertion or removal of the insert.
It will be appreciated that, in the embodiments shown in
Reference will now be made to
As before, there is formed in the clamping jaw 3 a throughgoing aperture 14, but in this embodiment there is not formed any through-going aperture in the base jaw 4. As seen in
In a modified embodiment shown in
In a still further modification shown in
Whilst in the embodiments specifically described above clamping retention of a cutting insert having substantially parallel upper and lower surfaces has been described, it will be readily appreciated that the present invention can be extended to the so-called “wedge clamping” of inserts having a wedge-shaped body portion arranged to be retained within a corresponding wedge-shaped slot formed in the holder blade.
It will be furthermore understood that the present invention is not restricted to any particular kind of cutting insert such as, for example, the cutting insert specifically illustrated, but is readily applicable to other forms of cutting inserts.
Claims
1. A cutting tool assembly comprising:
- a) a rigid holder blade, said rigid holder blade comprising: a body portion, a base jaw integrally formed with said body portion, a clamping jaw having a leading portion, said clamping jaw being integrally formed with said body portion and being resiliently and pivotally displaceable relative to said base jaw, an insert receiving slot having a leading portion and a trailing portion, said slot being defined between said clamping jaw and said base jaw and being adapted to receive an exchangeable cutting insert, a displacement surface formed in said clamping jaw, said displacement surface being spaced apart from said insert receiving slot and located substantially on said clamping jaw leading portion, and a supporting surface provided on said body portion, said supporting surface being spaced apart from said displacement surface, the arrangement being such that a displacing force applied between the supporting and displacement surfaces to move said surfaces relative to each other results in a outwardly directed resilient pivotal displacement of said clamping jaw relative to said base jaw;
- b) an insert receiving slot opening key having a pair of spaced apart prongs, a first prong of said key adapted to engage said supporting surface and a second prong of said key adapted to engage said displacement surface for applying said displacing force; and
- c) means to force apart said first and second prongs, said means including a wedge-like spacer.
2. A cutting tool assembly comprising:
- a) a rigid holder blade, said rigid holder blade comprising: a body portion, a base jaw integrally formed with said body portion, a clamping jaw having a leading portion, said clamping jaw being integrally formed with said body portion and being resiliently and pivotally displaceable relative to said base jaw, an insert receiving slot having a leading portion and a trailing portion, said slot being defined between said clamping jaw and said base jaw and being adapted to receive an exchangeable cutting insert, a displacement surface formed in said clamping jaw, said displacement surface being spaced apart from said insert receiving slot and located substantially on said clamping jaw leading portion, and a supporting surface provided on said body portion, said supporting surface being spaced apart from said displacement surface, the arrangement being such that a displacing force applied between the supporting and displacement surfaces to move said surfaces relative to each other results in a outwardly directed resilient pivotal displacement of said clamping jaw relative to said base jaw;
- b) an insert receiving slot opening key having a pair of spaced apart prongs, a first prong of said key adapted to engage said supporting surface and a second prong of said key adapted to engage said displacement surface for applying said displacing force; and
- c) means to force apart said first and second prongs, said means including a fixed prong and an eccentrically rotatable prong.
3. A substantially rigid holder blade for use in a cutting tool assembly comprising:
- a) a body portion;
- b) a base jaw integrally formed with said body portion;
- c) a clamping jaw integrally formed with said body portion;
- d) said jaws being located opposite one another and defining therebetween a cutting insert retaining slot within which a cutting insert can be spring clamped;
- e) slot leading and trailing portions;
- f) clamping jaw leading and trailing portions respectively and substantially adjacent said slot leading and trailing portions;
- g) said clamping jaw being resiliently and pivotally displaceable about its trailing portion;
- h) a displacement surface formed substantially on said clamping jaw leading portion and spaced apart from said retaining slot; and
- i) a supporting surface formed on said holder blade spaced apart from said displacement surface;
- j) the arrangement being such that a displacing force applied between said supporting and displacement surfaces to move said surfaces relative to each other results in outwardly directed resilient pivotal displacement of said clamping jaw with respect to said base jaw for insertion into and withdrawal from said slot of said cutting insert.
4. A holder blade according to claim 3 wherein said clamping jaw trailing portion is coupled to said body portion via a relatively narrow neck portion of a reduced height dimension as compared with a height dimension of the clamping jaw leading portion on which said displacement surface is formed, the dimensions being transverse to a longitudinal direction of said clamping jaw.
5. A holder blade according to claim 4 wherein a first aperture is formed in said clamping jaw leading portion having an aperture rim constituting said displacement surface.
6. A holder blade according to claim 5 wherein a second aperture is formed in said holder blade spaced from said first aperture and having an aperture rim constituting said supporting surface.
7. A holder blade according to claim 6 wherein said second aperture is formed in said base jaw substantially opposite said first aperture.
8. A holder blade according to claim 6 wherein said second aperture is formed substantially adjacent said clamping jaw trailing portion.
9. A holder blade according to claim 5 wherein said supporting surface is formed on an edge surface of said holder blade constituting a continuation of trailing edge surface of said clamping jaw.
10. A holder blade according to claim 5 wherein said supporting surface is formed as a trailing extension of said insert retaining slot.
11. A cutting tool assembly comprising:
- a rigid holder blade as claimed in claim 3; and
- an insert receiving slot opening key having a pair of spaced apart prongs, a first prong of said key adapted to engage said supporting surface and a second prong of said key adapted to engage said displacement surface for applying said displacing force.
12. The assembly according to claim 11 wherein a rotational movement of said key about said first prong displaces said clamping jaw relative to said base jaw.
13. The assembly according to claim 11 further comprising means for displacing said prongs apart.
14. The assembly according to claim 13 wherein said means for displacing said prongs apart includes a wedge-like spacer.
15. The assembly according to claim 13 wherein said means for displacing said prongs apart includes a fixed prong and an eccentrically rotatable prong.
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Type: Grant
Filed: Feb 23, 2011
Date of Patent: Oct 9, 2012
Assignee: Iscar, Ltd. (Tefen)
Inventor: Jacob Friedman (Kfar Vradim)
Primary Examiner: Boyer D Ashley
Assistant Examiner: Sara Addisu
Attorney: Womble Carlyle
Application Number: 13/033,421
International Classification: B23B 27/04 (20060101);