GB2443488A

GB2443488A - Seat Cutter for taps or valves

Info

Publication number: GB2443488A
Application number: GB0622016A
Authority: GB
Inventors: John Arthur Collier; Jon Norton
Original assignee: Monument Tools Ltd
Current assignee: Monument Tools Ltd
Priority date: 2006-11-04
Filing date: 2006-11-04
Publication date: 2008-05-07
Also published as: GB0622016D0

Abstract

A cutter member (10) for a tool for cutting the seats of taps has an end face (13) in which at least one slot (14) extends inwardly from the periphery of the cutter member for receiving a cutting element (21). Additionally, at least part of the cutting element and its associated slot are respectively shaped so as to prevent movement of the cutting element out of the slot in a direction perpendicular to the end face/length of the slot. In use, the cutting elements define a cutting surface; thereby variation of the design of the cutting.

Description

SEAT CUTTER FOR TAPS OR VALVES

This invention relates to a cutter member for a tool for cutting the seats of taps, valves or faucets (hereafter referred to as taps').

In our U.K. Patent Specification No. 2137915 A there is disclosed a tool for reseating a tap and also an improved cutter member for such a tool.

In particular the cutter member is easier to produce than previous cutter members.

Other forms of tap reseating cutter members are disclosed in U.K.

Patent Specification No. 2184673 and No. 2234198.

An object of the invention is to provide a cutter member for a tap seat cutting tool which is improved as compared to known designs.

According to a first aspect of the invention there is provided a cutter member for a tool for cutting the seats of taps, the cutter member having mounting means whereby the cutter member can be mounted for rotation or angular movement about an axis, and an end face in which at least one slot extends inwardly from the periphery of the cutter member, the or each slot receiving a cutting element, at least parts of the cutting element and its associated slot respectively being shaped so as to prevent movement of the cutting element out of its associated slot in a direction perpendicular or substantially perpendicular to said end face/length of the slot.

Preferably the cutting element has at least a part of complementary or substantial complementary shape to at least part of its associated slot.

More preferably the or each slot is machined, for example milled, in said end face of the cutter member. Most preferably, said end face is flat, and desirably the cutter member is cylindrical. However it could be conical, for use on concave shaped seats.

Conveniently the cutting element is of carbide material. Part of the cutting element protrudes beyond said end face, thus offering up a cutting edge of the cutter member. The design of the cutting edge can be varied to suit the best or required performance. The cutting elements do not require heat treatment, shaping or grinding after being received, by sliding, into their respective slots. Cutter wear will generally be negligible as the material used for the seat to be cut is usually made of brass.

Advantageously more than one slot is provided in the end face extending inwardly from said periphery. Varying angles of slots relative to the centre point of the cutter member or the cutter member periphery can be used according to preference.

In a preferred embodiment, the slots of the cutter member are peened over at their respective open ends at the periphery, so as to form an obstruction to sliding movement of the cutter elements out of their associated slots in a direction perpendicular to said axis. By this means the cutter elements are retained laterally in their slots in use.

In one embodiment the slots are of dovetail cross-section, whilst in an alternative embodiment an inner part of the slot is of part-circular cross-section and the remainder of the slot is of narrower straight cross-section.

Thus in each case the slot is narrower at its open area at said end face of the cutter member. Other slot shapes to retain a cutter element against movement out of the slot in a direction perpendicular to said end face are however possible. The slots could be straight or arcuate, the associated cutter elements in the latter case being matchingly curved.

The invention also relates to a tool for cutting the seat of taps, the tool including a cutter member according to said first aspect of the invention.

In a third aspect of the invention, there is provided part of a cutter member for a tool for cutting the seats of taps, the cutter member having mounting means whereby the cutter member can be mounted for rotation or angular movement about an axis, and an end face in which at least one slot extends inwardly from the periphery of the cutter member, the or each slot being intended to receive, in use, a cutting element, with at least parts of the cutting element and its associated slot respectively being shaped so as to prevent movement of the cutting element out of its associated slot in a direction perpendicular or substantially perpendicular to said end face/length of the slot, in use.

The invention will now be described by way of example, with reference to the accompanying drawings in which: Figure 1 is a perspective view showing a lower end face of one embodiment of a cutter member of the invention, with cutting elements of the member not being shown, Figure 2 is a perspective view showing an end face of another embodiment of a cutter member of the invention, with cutting elements of the member not being shown, Figure 3 is a view like Figure 1, to an enlarged scale, with the cutting elements being shown, Figure 4 is a view like Figure 3, of a still further embodiment of a cutter member of the invention, and Figure 5 is a view like Figure 2, to an enlarged scale, with the cutting elements being shown.

As referred to above, our prior UK Patent Specification No. 2137915 relates to a tool for cutting the seats of taps or valves and also to a cutter member for such a tool. In that specification the tool is described as having a feed screw which extends axially through, and in screw-threaded engagement with, an internally threaded axial bore in a centering member 10 which is adapted for engagement with the rim of a tap housing to centre the tool so that it is co-axial with the tap. Extending rotatably through an axial bore in the feed screw is a central spindle which carries at its upper end a handle, above the upper end of the feed screw, and carrying at its lower end, below the lower end of the feed screw 12, a cutter member. Although it may well be possible to use a cutter member of the present invention with various different types of tap reseating tools, it is primarily intended that a cutter member of the present invention is used with the tool described and illustrated in our above-mentioned prior British patent specification.

Accordingly it is intended that a cutter member of the present invention merely replaces the cutter member described and shown in that earlier

specification.

With regard to Figure 1, it can be seen that the cutter member 10 has the form of a generally cylindrical body with a central circular-section bore 11 which is internally screw-threaded, so that into said bore can be screwed a screw-threaded end portion of the central spindle of the tool described and illustrated in our earlier patent specification, in order to locate the cutter member on the spindle. The cutter member has a cylindrical peripheral surface 12, a planar upper surface, normal to the central axis of the member and a lower end surface having the form of a plane 13, also normal to the central axis of the member.

With the cutter member of the invention, the lower end surface defined by the plane 13 has therein at least one slot extending inwardly from the periphery of the cutter member 10. In the embodiment of the invention shown in Figure 1, there are three straight equi-angularly spaced radial slots 14 in the lower end surface, each slot extending inwardly from the cylindrical peripheral surface 12 and terminating short of the central circular bore 11, which is shown stepped down. In an alternative embodiment there could be at least one diametral slot, interrupted by the bore 11. In the Figure 1 embodiment, each slot 14 is of dovetail cross-section along its length, each slot being open at its one end at the peripheral surface 12 and also longitudinally at the narrower end part of the dovetail form. The depth of the slot in the surface 15 can be varied as required, but as seen from Figure 1, the depth of each slot is approximately a quarter of the depth of the cylindrical surface of the cutter member 10 between its upper and lower planar surfaces. As will be explained and described hereinafter, the complete cutter member incorporates respective cutting elements in the slots 14, but in order clearly to show the shape of the slots, such cutting elements are not shown in Figure 1.

Similarly the cutting elements are not shown in Figure 2, which shows a cutter member 15 of similar form to that shown in Figure 1. However with the Figure 2 arrangement, the straight slots 16 provided in the lower end surface 17 of the cutter member 15 are not radial, but are instead inclined at an acute angle in the surface 17 to a radius extending from the central axis of the cutter member 15 to the peripheral surface 18 at which the open end of the slot is positioned. In addition to being differently disposed in the end surface of the cutter member 10, as compared to the Figure 1 embodiment, the slot 16 of the Figure 2 embodiment is also of a different cross-sectional shape. As can be seen from Figure 2, the bottom part of the slot is part-circular as at 19, with the remaining, upper part of the slot, as viewed in Figure 2, being formed by a pair of straight, parallel spaced-apart facing wall surfaces, one of which is shown denoted by the numeral 20. Accordingly although in a different manner to that for the slot 14, it will be understood that the slot 16 is also narrower where it opens onto the lower end surface of the cutter member, as compared to the remainder of the slot. As will be explained, this is used to prevent the cutting element moving out of its slot in a direction perpendicular or substantially perpendicular to the end face, and thus to the length of the slot, when in use.

Figure 3 shows, as an enlarged view, a cutter member 10 shown in Figure 1 but with a cutting element now received in each of the three slots.

Each cutting element is in the form of an insert 21 made of material such as sold carbide. Accordingly, as shown in Figure 3, the cross-sectional shape of the insert 21 matches that of the dovetail slot, so that when the insert is slid in longitudinally along the slot, it can be positioned at an appropriate position along the slot, and, in one embodiment, the open end of each slot at the peripheral surface 12 can be peened over so as to form an obstruction to the exit of the slot, thus retaining the insert during use against its sliding out of the slot in the longitudinal direction. It will be understood that the matching dovetail shape of the insert with its associated slot ensures that the insert cannot move out of the slot in a direction perpendicular or substantially to the plane 13, i.e. in a direction perpendicular or substantially perpendicular to the longitudinal sliding direction referred to in respect of the peening over of the ends of the slots respectively. Accordingly when the cutter insert is connected to the cutting tool and is in use, the carbide inserts will not fall out of the flat planar lower end face of the cutter member.

Additionally the cutter insert will not twist in relation to its attitude in its slot.

Preferably, but not essentially, the cutter member is cylindrical, and also preferably, but not essentially, the slots are milled in the flat end face of the cutter body. Other shapes of cutter member can be utilised, such as conical, which may be used on concave shaped seats. The number of slots can be as few as one, this extending wholly across the face of the cutter member, or there may be as many slots as are practicable according to the preferred design and application. However usually there will be two or three slots. The shapes of the slots can be varied and varying angles of slots relative to the centre point of the cutter member or cutter member circumference can be used according to preference. The design of the cutting edge of the carbide inserts can be varied to suit the best or required performance. For example the cutting edge could be other than a straight line. These inserts will not require shaping, heat treatment or grinding after insertion in the machined slots of the cutter member. It will be noted that the wear of the cutter will be negligible as the material used for the seats discussed is normally made of brass.

The carbide insert shapes are made to match the slots cut in the cutter member so that part of the insert protrudes beyond the flat end surface of the cutter member, thus offering up one or more cutting edges for the completed cutting member. The shapes of the cutting surfaces can be whatever shape is needed for the particular application. The solid carbide inserts may be produced by molding or any other suitable means.

The cutter member 22 shown in Figure 4 is of a similar form to the cutter member shown in Figure 3, but differs in that the three slots 23 in the end face 24 of the cutter member are not radial, but are at an acUte angle to the radial direction as shown for the slots 16 in Figure 2. Otherwise the arrangement with the Figure 4 embodiment is the same as with the Figure 3 embodiment, in that the cross-section of each slot is of dovetail form as is the cross-sectional shape of each carbide insert 25. As with the Figure 3 arrangement, the respective ends of the slots can be peened over to prevent the inserts sliding longitudinally out of the slots at the periphery 26 of the cutter member. Again the matching dovetail shapes of the slots and the respective inserts prevents movement of the cutting elements out of their associated slots in a direction perpendicular to the end face.

Figure 5 is an enlarged view of the cutter member shown in Figure 2, but with respective inserts 27 now received in the respective slots 16. As with the other embodiments, the ends of the slots which are open can be peened over to prevent the inserts 27 sliding longitudinally out of these slots.

As can be seen from Figure 5, the cross-sectional shape of each insert matches that of the slot, in that each insert has an inner part-circular form 28 and an outer or upper (as viewed) rectangular/square form 29, the part-circular form matching the lower slot part 19 and the remainder of the insert matching the shape of the part of the slot between the upper wall surfaces 20 and extending therefrom above the plane of the end surface 17. Accordingly the cutter elements in the form of the inserts 27 each define a cutting surface as has been described by the embodiment shown in Figure 3, and the peening over of the ends of the slots taken together with the matching cross-sectional shapes ensures that the inserts remain in their respective associated slots. As explained, there can be no longitudinal sliding of an insert out of its slot due to the peening over, and movement of the cutting element out of its associated slot in a direction perpendicular to the end face is prevented by way of each slot being narrower at the end face than within the depth of the cutter member itself. This is true whether the slot is dovetailed or other forms shown in Figures 2 and 5. It will thus be appreciated that other shapes of slot could be used to prevent the insert movement referred to. Although slots 14 have a depth approximately a quarter of the depth of the peripheral surface 12, whilst the slots 16 have a depth approximately one third of the depth of the surface 18, it will be understood that the depth could be varied as required and moreover each insert could completely fill the length of the slot rather than the arrangement schematically shown.

-10 -The use of separate cutting inserts rather than producing integral cutting surfaces on the cutter member body itself, for example as with our earlier British patent specification, facilitates manufacture of the cutter member, which it is also believed would provide improved performance, additionally being versatile in that it allows for replacement of the cutting inserts as required to allow for different seats to be cut.

Although shown as straight, the slots in all the embodiments (and thus their associated cutting inserts) could be arcuate, and this may lead to improved cutting. Moreover the slots need not extend parallel to the respective upper and lower surfaces of the cutter member, but could be angled relative thereto. It is also to be noted that for a cutter member with more than one slot, it is not essential that all of the slots are of the same form, either in terms of cross-sectional shape (dovetail etc.), orientation (radial etc.), or attitude (parallel to cutter member surfaces etc.). Thus a mixture of slot forms could be provided.

Claims

1. A cutter member for a tool for cutting the seats of taps, comprising; mounting means whereby the cutter member can be mounted for rotation or angular movement about an axis; an end face in which at least one slot extends inwardly from the periphery of the cutter member whereby the or each slot receives a cutting element; and at least parts of the cutting element and its associated slot respectively being shaped so as to prevent movement of the cutting element Out of its associated slot in a direction perpendicular or substantially perpendicular to said end face/length of the slot.

2. The cutter element of claim 1 wherein the or each slot is machined, for example milled, in said end face of the cutter member.

3. A cutter member of claims 1 or 2 wherein the end face is flat.

4. A cutter member of claims 1 or 2 wherein the end face is conical.

5. A cutter member of any preceding claim wherein the cutter member is cylindrical.

6. A cutter member of any preceding claim wherein the slots of the cutter member are peened over at their respective open ends at the periphery.

7. A cutter member as described in claim 6 wherein, the peening forms an obstruction to sliding movement of the cutter elements out of their -12 -associated slots in a direction perpendicular to said axis, retaining the cutter elements laterally in their slots in use.

8. A cutter member of any preceding claim wherein part of the cutting element protrudes beyond said end face.

9. A cutter member of any preceding claim wherein the cutter element is of carbide material.

10. The cutter element of any preceding claim wherein the cutting element has at least a part of complementary or substantial complementary shape to at ICdSL palL oi IL du..1aLu IUL.

11. The cutter element of claim 10 whereby the relative sizes of the cutting element and its associated slot match such as to prevent the insert from falling out of the slot.

12. The cutter element of claim 10 wherein at least one of the slots are of dovetail cross-section.

13. The cutter element of claim 10 wherein at least one of the slots has an inner part of the slot of part-circular cross-section and the remainder of the slot of narrower straight cross-section.

14. A tool for cutting the seat of taps including a cutter element as described in any one of the preceding claims. -13

15. A cutter element substantially as hereinbefore described with reference to Figures 1 and 3 or Figures 2 and 5 or Figure 4 of the accompanying drawings.