The present invention relates to cutting tool assemblies, for metal cutting processes in general, and to cutting tool assemblies with a removable tool head for holding a cutting insert employed in turning and grooving operations, in particular.
Cutting tools may have a holder and a releasable tool head with an insert pocket for holding a cutting insert. The cutting insert is usually formed of a hard material, such as cemented carbide. The releasable tool head is removably attached to the holder, by an attachment element. Such attachment element is usually a screw which passes through a pre-formed through hole in the releasable tool head and engages a corresponding threaded hole formed in the holder body. Examples of such cutting tools are disclosed in U.S. Pat. No. 3,289,273, U.S. Pat. No. 3,500,523, U.S. Pat. No. 4,057,884, U.S. Pat. No. 4,066,376, U.S. Pat. No. 5,555,784, U.S. Pat. No. 6,702,526, U.S. Pat. No. 7,086,812, U.S. Pat. No. 7,118,311, U.S. Pat. No. 7,240,593, U.S. Pat. No. 7,578,640 and US2010/0254774.
It is an object of the subject matter of the present application to provide an improved novel cutting tool assembly with a removable tool head for holding a cutting insert, wherein the tool head does not require a through hole for clamping to the holder.
In accordance with the subject matter of the present application, there is provided a cutting tool assembly, comprising
wherein in an assembled position of the cutting tool assembly:
For a better understanding of the present application and to show how the same may be carried out in practice, reference will now be made to the accompanying drawings, in which:
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity, or several physical components may be included in one functional block or element. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.
In the following description, various aspects of the subject matter of the present application will be described. For purposes of explanation, specific configurations and details are set forth in sufficient detail to provide a thorough understanding of the present invention. However, it will also be apparent to one skilled in the art that the subject matter of the present invention can be practiced without the specific configurations and details presented herein.
Attention is first drawn to
Reference is further made to
The holder clamping portion 112 extends along a clamping axis M, and has a threaded bore 115 and at least one forward-facing holder support surface 146. According to some embodiments, the clamping axis M extends perpendicular to the holder axis H. The holder support surfaces 146 are located upwards from the threaded bore 115, along the clamping axis M. According to some embodiments of the present invention (e.g.,
The removable tool head 104 has a longitudinal tool head axis T extending in the rearward to forward directions DR, DF, and a tool head bottom end 131 having a tool head mating surface 132. The tool head 104 includes a tool head front surface 120 and an opposite tool head rearward surface 122, both extending in the upward to downward direction U, D. The tool head front and rearward surfaces 120, 122 are distanced by a tool head length L (
The tool head rearward surface 122 has an external tool head clamping recess 124, extending upwards from the tool head bottom end 131. According to some embodiments, the tool head clamping recess 124 extends perpendicular to the tool head axis T. The tool head clamping recess 124 includes a clamping surface 126, extending from the tool head rearward surface 122. The tool head 104 includes a tool head top end 133, provided with a tool head top surface 128 extending from the tool head rearward surface 122, towards the insert pocket 130. As seen in the figures, the external tool head clamping recess 124 extends upwards from the tool head bottom end 131 to the tool head top end 133.
The holder mating surface 114 includes a beveled female portion 116, partially limited by a plurality of holder mating sidewalls 140. According to some embodiments, the holder mating sidewalls 140 may be connected by a unitary holder sidewall 118, which diverges towards the holder clamping portion 112 (i.e., in the rearward direction DR).
The tool head mating surface 132 includes a male portion 134 projecting therefrom, partially limited by a plurality of tool head mating sidewalls 138. According to some embodiments, the tool head mating sidewalls 138 are connected by a unitary tool head sidewall 136, which diverges towards the tool head clamping recess 124.
Reference is further made to
A tool head abutment surface 135 extends on the tool head mating surface 132, adjacent to the tool head mating sidewalls 138, substantially parallel to the male portion 134. The tool head mating sidewalls 138 conform in shape, size and orientation, to the holder mating sidewalls 140, in order to allow firm abutment between the mating sidewalls 138, 140 in the assembled position.
The holder mating surface 114 and the tool head mating surface 132 are tilted by a tilt angle δ relative to the holder axis H and the tool head axis T, respectively (as indicated in
With further reference to
Reference is further made to
The male portion 134 is substantially parallel to the tool head abutment surface 135, and spaced apart therefrom by a first distance H1. The female portion 116 is substantially parallel to the holder abutment surface 144, and spaced apart therefrom by a second distance H2. In a preferred embodiment of the present invention, the second distance H2 is the same as, or greater than the first distance H1, in order for the tool head abutment surface 135 to abut the holder abutment surfaces 144, when the male portion 134 is received within the female portion 116.
With further reference to
The tool head fastening member 106 is a fastening screw, having a substantially circular head portion 154 and an narrower elongated threading portion 156, extending from the head portion 154 along a screw axis S. The head portion 154 has a head clamping surface 148, facing towards the elongated fastening portion 156, and a fastening support surface 150, extending circumferentially on the head portion 154.
The cutting tool assembly 100 can be moved from a disassembled position (
The tool head fastening member 106 is then fitted into the holder clamping portion 112, such that the screw axis S coincides with the clamping axis M, and the threading portion 156 threadingly engages the threaded bore 115. The tool head fastening member 106 is screwed into the holder clamping portion 112, by rotating in a screw direction R about the screw axis S (
The cross section view of
In the assembled position, the tool head mating sidewalls 138 firmly abut the holder mating sidewalls 140 in a dovetail manner, and so the tool head mating surface 132 forms a dovetail connection with the holder mating surface 114. Further, the tool head abutment surface 135 firmly abuts the holder abutment surfaces 144. The dovetail connection and the external clamping of the tool head 104 by the tool head fastening member 106 are the only means for retaining the tool head 104 on the tool holder 102. The angled dovetail structure of the mating sidewalls 138, 140 prevents the tool head 104 from being pulled out of the tool holder 102, for example, by a mere upward or forward force. Thus, the tool head 104 is firmly retained in the tool holder 102, withstanding various operational forces (e.g., longitudinal, radial or lateral forces), without moving, shaking or being pulled out of the tool holder 102.
Further in the assembled position, the cutting tool assembly 100 may be provided with the cutting insert 162 in the insert pocket 130 of the tool head 104, and then employed in metal cutting operations. The cutting insert 162 may be retained within the insert pocket 130 prior to assembly of the tool head 104 onto the tool holder 102, since the mounting of the tool head 104 to the tool holder 102 does not involve contact with the insert pocket 130. As explained herein, assembling the cutting tool assembly 100 involves only contact with the rearward surface 122 and the bottom end 131 of the tool head 104. Alternatively, the cutting insert 162 may be retained within the insert pocket 130 after assembly of the tool head 104 onto the tool holder 102, since a clamping arrangement thereof would not involve contact with the rearward surface 122 or the bottom end 131 of the tool head 104.
It is noted that the tool head 104 may include any type of clamping arrangement for retaining the cutting insert 162. For example, the tool head 104 may include an insert clamping recess 160 extending generally downwards from the insert pocket 130 for receiving a clamping pin for contacting the cutting insert 162 and attaching it to the insert pocket 130. The tool head 104 may further include a forward recess screw 164 for engaging and pressing against the clamping pin.
The removable tool head 104 has a substantially rectangular chest form, having a tool head length L and a tool head width W (indicated in
This external clamping structure presents an advantage to the cutting tool assembly 100, in particular for a tool head 104 with small dimensions of the tool head length and width L, W, which would limit the available space for making a through hole in the tool head 104, however with sufficient space for forming the external clamping recess 124, as described herein above. In another example case, if the insert pocket 130 of the tool head 104 includes an insert clamping recess 160 for receiving a clamping pin or a fastening screw for clamping the cutting insert, this may limit the available space for making another through-hole in the tool head 104. Thus, it would be advantageous to externally clamp the tool head 104 to the tool holder 102, rather than by a through-hole clamping.
Reference is now made to
Reference is now made to
Moving the cutting tool assembly 300 from the disassembled position to the assembled position is as described herein above with regards to the cutting tool assembly 100. In the assembled position, the holder's male portion 306 is received within the tool head's female portion 308, in a dovetail connection.
The holder mating surface 314 includes a plurality of holder mating sidewalls 310, which partially limit the male portion 306. The tool head mating surface 316 includes a plurality of tool head mating sidewalls 312, which partially limit the female portion 308, and are formed to abut the holder mating sidewalls 310 in a dovetail connection, when in the assembled position. The holder and tool head mating sidewalls 310, 312 diverge in the forward direction, in order to form a forward fit between the mating surfaces 314, 316 under the force applied by the tool head fastening member 106 on the tool head clamping recess 124 (as opposed to diverging towards the clamping recesses 112, 124, as in the cutting tool assemblies 100, 200).
While the present invention has been described with reference to one or more specific embodiments, the description is intended to be illustrative as a whole and is not to be construed as limiting the invention to the embodiments shown. It is appreciated that various modifications may occur to those skilled in the art that, while not specifically shown herein, are nevertheless within the scope of the invention.