US3458961A - Grinding tools - Google Patents

Description

5, 1969 E. HENRY-BIABAUD GRINDING TOOLS 2 Sheets-Sheet 1 VFiled sept. v. 196e 5, 1969 E. HENRY-BIABAUD 3,458,961

GRINDING TOOLS United States Patent O Inf. cl. lmb 9/02 U.S. Cl. 51-338 4 Claims ABSTRACT OF THE DISCLOSURE A tool for grinding or honing the inside of a bore or series of axially spaced bores having axially spaced split rings to which abrasive means are mounted and which may be separately and precisely adjusted as to cutting diameter. The extensible rings are each split longitudinally and encircle a sleeve having radially extending slots and a thrust member is positioned in each slot with a roller at each of its ends to positively position it within the slot. The rollers can be replaced by others of different diameters to longitudinally displace the corresponding thrust member with respect to a tapered expansion surface bearing against the inner surface of that thrust member to thereby precisely adjust the outside diameter of the portion of the split ring axially outwardly of the member and thus the cutting diameter of the abrasive means.

This invention relates to tools used for grinding and, in particular, those for carrying out the finishing operation known as honing In the honing of cylindrical bores in thin-walled workpieces, the quality obtained is improved if the tool is shaped to oppose elastic deformation of the workpiece.

To that end, the points at which the tool is brought against the workpiece should be as close together as possible; but conventional laps or grinders do not prevent such elastic deformation, because the sum of those arcs of the tool which are in contact with the workpiece over the same circumference is not, on average, more than 35 to 50.

The present invention is concerned with a lap or grinder, suitable more particularly for honing, having a practically continuous cylindrical surface, along the entire length of which, if desired, abrasive materials can be deposited in the form of a diamond agglomerate.

The distinguishing feature of the lap or grinder here proposed is the provision of at least one cylindrical ring covered on the outside with abrasive materials, this ring, which is elastic and can undergo changes of shape, being mounted under tension on a series of thrust members which have radial motion.

In one recommended form of the invention, means are provided whereby a liquid can be introduced into the lap, the ring containing orifices through which this liquid can escape.

In use, this arrangement enables the liquid owing beneath the ring to form a continuous film, which removes the heat generated, lubricates the working surfaces and opposes the entry of foreign bodies into the bore while itis being treated.

One practical form of a lap conforming to the invention is described hereunder by way of example, no limitation of scope being thereby implied, in conjunction with the accompanying drawings, in which:

FIGURE l shows the lap partly in elevation and partly in axial section;

FIGURE 2 is an axial section along line II-II in FIGURE l;

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FIGURE 3 is a cross-section along line III-III in FIGURE l;

FIGURE 4 is a cross section along line IV-IV in FIGURE 1; and

FIGURE 5a is a section along line V-V in FIGURE 2 and shows, in conjunction with FIGURES 5b and 5c, how the sleeve diameters can be varied.

The lap, in the form illustrated, comprises a sleeve 1, which can be fixed to spindle 2 of a grinding machine by means of nut 3. On one end of the sleeve 1 are two projections 1a, which engage in recesses in the spindle 2 and transmit the rotary drive to the sleeve.

An expander rod, numbered generally 4, is mounted with freedom to slide in the axis of member 1. This rod is fixed to a short spindle 25, to enable it to be connected to the expander rod control of the grinding machine. The rod 4 incorporates two expansion cones 4a and 4b, and two cruciform bearing faces 4c and 4d.

Around each expansion cone 4a and 4b there are disposed a number of thrust members 5, mounted with freedom to slide within radial passages 6 in the sleeve, with some degree of longitudinal play. Over each set of thrust members is fitted, under tension, a split ring 7a or 7b, which is faced with abrasives 8 deposited in the form of diamond agglomerate. A key 9, fitted in a slot 10 of the ring and a slot 11 of the sleeve, prevents the ring from rotating in relation to the sleeve (FIGURE 4). The slot 10 is in such a position, in relation to the split in the ring that the ring is pulled, not thrust. A packing seal 12, is provided between the two ends of the ring.

Each thrust member 5 contains a longitudinal slot 13, housing a fiat spring 14, held in position by a pin 15. The ends of the spring 14 serve to retain centering rollers 16, which bear against the side faces of the particular passage 6 and are held in V-shaped notches 17 at the ends of the thrust member (FIGURE 5a).

The two rings are held axially iny position by distance pieces 18a, 18b and l8r,` and by two pairs of half-shells, 19a and 19b, the whole being locked in place by a nut 20 and a locknut 21.

The locknut 21 has an exposed face 21a, against which one member (not shown) of a rotary seal, forming part of a liquid supply system, can be brought to bear.

This system, indicated symbolically by an arrow 22, enables a liquid to be introduced into the lap and to reach rings 7a and 7b by virtue of the shape of the bearing faces 4c and 4d. The rings 7a and 7b contain orifices 23, spaced to correspond with abrasive additions 8, through which this liquid can escape.

The lap is inserted, while in the contracted condition, into the bore or bores to be worked. The grinding machine imparts both rotary and translational motion to the lap; in addition, the rod 4 is moved axially in relation to the sleeve by means of a special drive, so that, under the action of cones 4a and 4b, thrust members 5 are driven radially outwards. These thrust members alter the shape of rings 7a and 7b, increasing their diameters.

The film of liquid escaping from the orifices 23 washes away the swarf, lubricates the working surfaces and prevents the rings from overheating.

When the desired diameter has -been obtained, the machine withdraws the rod 4, the thrust members 5 being restored to their original positions by the rings 7a and 7b.

The diameters of the rings can be varied to some extent. All that is needed for this purpose is to replace the rollers 16 of one set of thrust members 5 with rollers of different diameters, the sum of the diameters of two rollers at the ends of a thrust member remaining constant. This results in off-setting the thrust members S to the left (FIGURE 5b) or to the right (FIGURE 5c), thus respectively reducing or increasing the diameter of the rings concerned by a few microns. It will be noted that the adjustment of one ring does not affect the other.

For changing rollers 16, there is no need to dismantle the lap. One need only withdraw the half-shells 19a and 19b and slide the rings axially.

It will be clear from the foregoing7 description that the lap here proposed makes it possible to use very accurate abrasive rings, without the need for touching-up in the course of fitting. The rings may have their abrasive faces 8 equidistant and close together and provided with symmetrical clearances according to particular ratios and cross-sections. They can be renewed after use, by replacement of the diamond agglomerate.

The initial tension on the rings in itself ensures the contraction of the working surfaces at the end of the cycle, without its being necessary to provide any special restoring device. This tension makes the lap insensitive to breaks in the workpiece surface and hence makes it possible to hone fiuted bores. In conjunction with the temperature control provided by the lm of liquid, it makes it possible for the fully expanded diameters to be faithfully reproduced.

Moreover, the lap may be designed to operate in one stage or more; in the case of a multi-stage lap, each stage can be adjusted independently, without the adjustment of the other stages being affected.

The invention should naturally not be regarded as limited to the practical examples described, but includes all variants thereof within its scope.

I claim:

1. A tool comprising a plurality of longitudinally split rings which are externally faced with abrasive material, a sleeve within each of said rings having circumferentially spaced outwardly opening slots, a thrust member in each of said slots having an inner surface engaged upon a longitudinally tapered expander surface, each of said thrust members engaging a roller at both of its ends to position it positively in one of said slots so that said rollers may be replaced by others of different diameter to precisely position it on said expander surface to thereby control the outside diameter of said sleeve and thus the effective working diameter thereof.

2. The tool defined in claim 1 further comprising an axially slidable expander rod positioned within said sleeve, said expander surfaces being on said rod so that said rod can be moved axially to radially position said thrust members.

3. The tool defined in claim 1 wherein the ends of said thrust members have radially extending notches, said rollers being engaged in said notches.

4. The tool defined in claim 1 wherein each of said rings being pretensioned and secured to said sleeve to prevent relative rotation between said sleeve and said ring at a location adjacent to said split thereon the side of said split which is defined by the edge of said ring which leads it as it rotates.

References Cited UNITED STATES PATENTS 1,796,060 3/1931 Summers 51-344 2,135,884 11/1938 Disco 51-355 2,427,085 9/ 1947 Allison 51-267 X 2,445,278 7/ 1948 Mitchell 51-346 2,694,277 11/ 1954 Speck 51-346 2,978,846 4/ 1961 Barron 51-206 3,324,603 6/1967 Nieniec 51--267 OTHELL M. SIMPSON, Primary Examiner

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