FR2515087A1 - DEVICE FOR MOUNTING A REPLACABLE SET OF RODING STONE ON A MAIN STONE HOLDER - Google Patents

Abstract

THE DEVICE ACCORDING TO THE INVENTION INCLUDES A MAIN STONE CARRIER 22 ON WHICH IS REMOVABLY FITTED A SET OF RUNNING STONE 24, CONSTITUTING A STONE AND A SOFT METAL SUPPORT PART. THIS SET IS INTENDED TO BE DISPOSED OF WHEN THE STONE IS WORN.

Description

DEVICE FOR MOUNTING AN ASSEMBLY

REPLACABLE OF RODING STONE

A MAIN STONE HOLDER

  The present invention relates to a device for mounting a replaceable assembly of lapping stone on a

main stone holder.

  Lapping heads and other similar devices

  laires on which lapping sets of stone have been used for many years and it

  There are many forms and achievements of these provisions.

  some of which have a single radially adjustable assembly and others of which have several circumferentially spaced stone assemblies, one or more of which are radially adjustable during a lapping operation to keep the stones in contact under pressure on the surface of the lapping work Many lapping stone sets and devices for setting them in motion have been designed and used in the past, including those described in United States patents

  from America N RE 18 763; 1,902,194; 1904.336, 1,946,041.

  1,982,836; 2,040,281; 2,815,615 and 3,378,962 In some known embodiments, the stones are fixedly mounted on stone holders which are then mounted on a head or the like, in different ways With these known embodiments, when the stones

  wear out, the sets of stone which generally include-

  their i ontaqe device is thrown away, or the old stones are removed and new stones are mounted These two procedures are long and costly for the user, especially in cases where the stone sets include a support and support in

expensive metal.

  The invention aims to eliminate these losses and expenses through the production and fixing of a new set of replaceable lapping stone which comprises

2 2515087

  a reusable main stone holder and a set of

  replaceable stone which can be mounted on the holder

  stone, the replaceable assembly comprising an inexpensive bearing part on which one or more stones are mounted The replaceable assembly according to the invention is mounted on the main stone holder in a new way using simple means which require only hand tools readily available for assembly and disassembly and so as to avoid loosening between the replaceable stone assembly and the replaceable stone holder, while at the same time ensuring

  time a positive coupling in rotation between them.

  When the stones in this device wear out and need to be replaced, the replaceable stone set can be quickly and easily separated from the main stone holder and replaced by another similar stone set. This results in minimal loss to the user and, due to the low price of replaceable stone assemblies, it is not economical to reassemble stones on existing support parts, which is long, expensive and requires equipment and materials Furthermore, since the support material on which the stones are fixed is inexpensive and is damaged by use, there is little loss to throw it rather than trying to reuse it by dismantling

  the worn stone and replacing it with a new one.

  An essential object of the invention is therefore to propose a set of disposable stone, relatively few

  expensive, to be mounted on main stone holders.

  Another object of the invention is to reduce the cost of regenerating a lapping device, in a

new similar condition.

  Another object of the invention is to propose a new device for mounting an assembly of stone

  replaceable on a main stone holder.

  Another object of the invention is to make the reassembly of stones on existing stone holders uneconomical.

225 5087

  Another object of the invention is to propose

  a new realization of a set of stone replaced

  cable and a main stone holder on which is mounted

the stone set -

  Yet another object of the invention is to reduce the time and effort required to mount a set of lapping stone on a stone holder in order to restore a lapping device in a new

  similar operating condition.

  Another object of the invention is to avoid mounting a set of stones in the wrong position

-on a main stone holder.

  Yet another object of the invention is to allow a replaceable stone assembly to be mounted on a main stone holder using tools

  simple and easily available.

  Another object finally of the invention is to -

  reduce the cost of maintaining a lapping head by

good working condition -

  Other features and benefits of

  the invention will appear during the description which

  will follow from several exemplary embodiments and with reference to the appended drawings in which: FIG. 1 is a side view of a set of lapping stone and its main support, produced according to the invention, FIG. 2 is a right end view of the device of Fig 1, Fig 3 is a side view and in partial section of the main stone holder only of the embodiment of Fig 1 and 2, Fig 4 is a right end view of the stone holder of Fig 3, Fig 5 is a top view of the upper part only of the stone holder of Fig 3, Fig 6 is a side view and in partial section of the part shown in Fig 5,

4 2 2515087

  Fig 7 is a right end view of the part of Fig 6, Fig 8 is a top view of the part of a replaceable stone assembly on which a stone is mounted, Fig 9 is a end of the piece of Fig 8, Fig 10 is a view of the right side of the piece of Fig 8, Fig 11 is a section on a large scale along line 11-11 of Fig 8, Fig 12 is a bottom view of the part of Figs 8 to 11, Fig 13 is a perspective view of a modified stone assembly, Fig 14 is a section showing the modified assembly of Fig 13 mounted on a stone holder main, Fig 15 is a section similar to that of Fig 14 but illustrating another modified embodiment of the device, Fig 16 to 18 are large-scale sections showing other embodiments of a

  device for fixing a set of replaced stone

  cable on the main stone holder, Fig 19 is a section showing a replaceable stone assembly fixed on a main stone holder by means of a special tool, Fig 20 is a section showing another embodiment of a device for fixing a replaceable stone assembly to a main stone holder by a means which does not require that the stone assembly be removed from the head on which it is mounted, this device being shown before assembly, FIG 21 shows the assembly of Fig 20 after the tool has completed the assembly between the replaceable stone assembly and the main stone holder, and Fig 22 is a section of the assembly of Fig 21 and 22 but in a position spaced from those G 5215 i 087

  represented in these latter figures.

  Among the figures, Fig 1 shows particularly

  lièrerent a device 20 which comprises a main stone holder 22 on which must be mounted a set of replaceable stones 24 The assembly 24 includes a stone mounting part 26, generally made of a relatively low-content material, for example zinc

  molded, cast aluminum or other similar material

  area, and on which can be mounted one or

  several honing stones, such as honing stone 28.

  Stone 28 can be attached to the mounting piece in different ways, but the preferred way is to glue it while the pieces to be joined are positioned and held in the correct position using

  a caliber or similar (not shown).

  The main stone holder 22 comprises an elongated rectangular plate 30 on which is mounted

  the stone assembly 24, and mounting parts shown

  sensed by racks 32 and 34 are fixed on it at opposite ends. For this fixing, the plate 30 has two holes 36 spaced apart with countersunk parts 37 (FIGS. 3, 5 and 6) near its opposite ends, and each of the racks 32 and 34 has a cylindrical end portion 38 of reduced diameter which penetrates into a respective hole 36 and, when thus positioned, is riveted as shown at 40 to form a secure connection in the opening portion milled 37 The racks 32 and 34 also include several teeth, as shown at 42, formed on its corresponding sides to mesh with a pinion which will be described later, arranged in a lapping head or other similar device, and intended to move radially the stone assemblies during a running-in operation in order to keep the stones in contact with the surface to be machined and to retract them when the head must be

25.15087-

  extracted or must be introduced into a room.

  The plate 30 of the stone holder 22 also includes

  : .nt two similar openings 54, arranged respectively-

  ment inside the openings 36, and centered laterally

  relative to the latter The holes 44 are used to mount the replaceable lapping assembly 24 on the stone holder 22 in order to ensure an assembly

  solid between them, as will be explained.

  Figs 8 to 12 show details on the support part 26 of the stone assembly 24 The part

  support 26, as already indicated, is preferably

  made of an inexpensive material, for example cast zinc, cast aluminum or any other relatively inexpensive material, and it has a lower surface 46 which rests on the upper surface of the plate 30 when it is mounted, and an inclined upper surface 48 which is the surface on which the stone 48 is fixed in a certain way, as explained above. The surface 48 is inclined with respect to the lower surface 46 and extends over the entire length of the piece 26 A positioning ledge 50 projecting upwards extends along one side of the surface 48, and the stone 28 is placed along this ledge as shown in FIG 2 The edge of the inclined surface 48 opposite the rim 50 extends to another inclined surface 52, which extends towards the front edge 54 of the

Exhibit 26.

  The lower surface 46 of the molded part 26

  comprises two tubular parts 56 of which it is solid

  and protruding as shown in Fig 9; and 11 The parts 56 extend from the surface 46 by a distance slightly less than the thickness of the plate 30 of the stone holder 22 and these parts 56 are spaced from each other and dimensioned so to penetrate towards the edge into the respective holes 44 of the plate 30 as shown in Fia 1 Each of the tubular parts 56 also has two opposite notches

2 2515087

  58, from its free end as shown in the

  Fig 10, il et 12 In addition, and as shown particularly

  In FIG. 11, cylindrical passages or recesses are formed in the tubular parts 56, and pass through these tubular parts 56 and partially penetrate into the body of the part 26 When the tubular parts E are positioned in the respective holes 44 of the plate 30, threaded parts, for example screws 62, are screwed into these tubular parts 56 as shown in FIG. 1 In this way, pressure is applied by the threads of the screws against the tubular parts 56, by cutting therein a thread and in them

  widening, thereby applying lateral force in engagement

  location in the holes 44 This results in a very

  relatively inexpensive installation and availability

  sition which facilitates and accelerates assembly and dismantling

  This means that to replace one of the sets of stone on the stone holder 22, it is sufficient that after the set 20 has been removed from the head on which it is mounted, to unscrew two of the screws 62 of the stone assembly 24 worn to remove it from the stone holder 22, and to mount a

  another similar set, using such a simple procedure.

  During disassembly of the worn stone assembly, it may

  it will be necessary to pierce the ends of the tubular parts

  loops 56 to loosen them, but this is generally not

not difficult to do.

  It is important according to the invention that the main stone holder 22 is reusable, because this part of the present device is preferably made precisely of relatively hard steel, and it is a relatively expensive piece. The only replaceable part is therefore the assembly of stone 24 which comprises the relatively inexpensive support 26, easily split or molded in large series, and the stones 28 themselves which are the parts of the device which engage and do the work, undergoing wear The stone sets 24 comprising the support parts 26 and the stones 28 can be produced relatively inexpensively in large series, the support part 26 preferably being made of a relatively soft metal, as has already been indicated, which can be deformed by the formation of the threads in the tubular parts 56 It should also be noted that the tubular parts 56 can be split, as represented by the two slots 58, although these slots are not p as necessary in certain cases Parts 56 can also have a single slot on one side or possibly three or more

  spaced slots, similar to slots 58 Note

  quer that when the stone assembly 24 is locked in position in the stone holder 22, the tubular parts

  56 can be damaged by the threads of parts 62.

  This may limit the possibility of repeatedly fixing the same set of stone 24, although it is possible

  to fix it again - once or twice if necessary

  saire It has been found that this is not a drawback since it is generally not economical to reassemble stones on a support piece and very often, when the stone or the set of stones has been used frequently, it is too worn to recondition it for a new use. Consequently, in the current situation, once a set of stones 24 has been mounted on a main stone holder 22, it is not necessary or desirable to reassemble them. again on the same or a

another main stone holder.

  The bearing part 26 of the stone assembly 24 can optionally also include a rim like the rim 64 (FIGS. 13 and 14) directed downwards along one or more sides. The rims 64 stiffen to a certain extent. the assemblies 24 and help to avoid warping and bending, and these flanges can be positioned to be directed downwards, spaced from the adjacent sides of the main stone holder on which they are mounted as shown in Fig 14 It has recognized

  that when they extend over the ends of the

  seems 24, these edges are more useful than those that only extend along the sides but, in most

  cases, these ledges are not essential.

  The dimension and / or the spacing and / or the posi-

  tion of the holes 44 and of the tubular parts 56 can be chosen to avoid a mounting error and the mounting on a main stone holder of a set of stones which is not the right one. For example, it is possible to shift the position of the two holes 44 and the respective tubular positions 56 towards one end of the device

  to avoid mounting a set of stones backwards.

  The position of the side flanges, like the flanges 64, can also be such that it prevents an operator from accidentally or inadvertently mounting an assembly

  of stone upside down on a stone holder.

  FIG. 13 represents a modified embodiment 24 A of the set of lapping stone 24 produced to receive two stones 28 A parallel and spaced The set

  24 A has a peripheral rim like the perimeter rim

  spherical 64, which extends all around, as well as around the plate 30 of the stone holder when it is positioned

  on the latter It also has two tubular parts

  spaced spaces that cooperate with holes 44 in the

  plate 30 of the main stone holder as mentioned above.

  The tubular parts 56 A can be split or not, at will. FIG. 14 is a section of the modified assembly A comprising the modified stone assembly 24 A mounted on the main stone holder 22, with the flange 64 extending at a distance around the sides of the stone holder.

  embodiment, the plate 30 is positioned in super contact

  with a surface of the stone assembly 24 A, as above, and the assembly between the stone assembly 24 A and the stone holder 22 is done in a similar manner to that described above in using threaded parts 62

  cooperating with each of the tubular parts 56 A The holder

  main stone 22 also includes racks, such as racks 32 and 34, which cooperate with an i O 0: 515087

  pig no 66 ds> placed in a mandrel, like a lapping head.

  -e ti non 66 is turned j: to radially move the

  _'mb Je 20 A from the strip already described.

  Fig. 15 illustrates another embodiment B which is similar to embodiment 20 A but which differs in the way in which the stone assembly 24 B and the plague 30 B are produced and assembled together In the modified embodiment 20 B, plate 30 B of the stone holder

  main has opposite edges 68 inclined or chan-

  braked which engage surfaces 70 inclined or chanfrel-

  born in a similar way, formed on the inner surface of the rim 64, on the support piece 26 B when they are thus engaged, a space is formed between the surface 72 on the piece 30 B of the stone holder and the area

  74 of support piece 26 B Also in the embodiment

  sation 20 B, the tubular parts 56 B of the support piece 26 B have a smaller diameter than that of the holes 44 W in the plate 30 B of the stone holder and when the threaded pieces 62 are tightened by means of a screwdriver or of a similar tool, a force is exerted pulling down and bending the support piece 26 B, thus pressing the inclined surfaces 68 and 70 against each other In certain

  applications, this method of assembly can be advantageous.

  In the embodiments 20 A and 20 B, arrangements are made to support two parallel and spaced stones, like the stones 28 A and 28 B Also in Figs 14 and 15, a circular outline W is also shown to show the cylindrical surface d a workpiece to be lapped by the present device When the surface is enlarged or when the stones are worn, it is necessary to rotate the pinion 66 to move the workpieces to be lapped outwards and keep them engaged on the surface to be machined D similarly, after a lapping operation is completed or before a lapping head is introduced into a surface to be machined, the pinion 66 must be rotated in the opposite direction to retract the stone assemblies so that the head to be broken in may be

  introduced into or removed from the workpiece.

  Figs 16 to 18 illustrate other means for fixing between a stone assembly, such as assembly 24 and the main stone holder 22; and particularly between the part 26 for mounting the stone assembly and the stone holder 22 According to FIG. 16, the fixing device comprises a grub screw

  blocking 80 The blocking screw 80 may include a 3 oge-

  ment for a key, like a hexagonal key, and the front end part of this screw 80 is preferably conical, as in 82, to facilitate its entry into the tubular part 56 The threads of the locking screw 80 can also be slightly tapered from one end to the other, the largest diameter being at the rear end, although this is not essential When the locking screw 80 is screwed into one of the tubular parts 56, it cuts its own net and, in doing so, el Mle expands the part 56 outwards, as already indicated, to establish a tight assembly in the hole 44 of the stone holder 22 An advantage of the embodiment of Fig 16 is that the locking screw 80 does not need to

  have a head which, in some cases, limits the movement

  inwardly of the lapping assembly on a lapping head This is especially advantageous in the case of small diameter heads and can allow a greater range of radial adjustment of the stone assembly without having to modify the body of the head to receive the heads of the screws. FIG. 17 illustrates the use of another form of threaded part 86 to effect the fixing, this form also not protruding from the plate 30 of the main stone holder. In this case, the threaded part 86 has a countersunk head 88 and the hole 44 in the plate, and possibly also the hole 60 in the tubular part 56 are modified somewhat by being milled to receive the screw head 88 In this embodiment, the hole 60 in the tubular part 56 is shown milled at 90 so that the head 88 engages there slightly before pressing on the milled part 92 of the hole 44 This produces a certain outward movement or an expansion of the part 56, in engagement in the hole 44 , improving the assembly. Fig 18 shows an embodiment in which a ball, such as the bearing ball 94 is

  forced or compressed in the hole 60 of the tubular part.

  The piece 94 is wide enough to expand the part 56 towards the outside, by engaging in the hole 44 The penetration depth of the ball 94 can be such that it maintains a pressure towards the outside on the tubular part 56, preferably in the region of

grooves 58.

  FIG. 19 illustrates the use of a tool which has a handle 102 and a threaded end portion 104 The thread 104 must be such that when it is screwed into the tubular part 56, it expands the latter towards the outside in engagement in the hole 44 The thread 104 can be tapered to facilitate the entry of the tool into the part 56, and the taper of the thread can also allow greater expansion when the tool is screwed into the hole, thus ensuring a rigid connection between the tubular part 56 and the hole 44 When the tool 100 has been used to expand the tubular part 56 into engagement in the hole 44, it is removed by unscrewing it, leaving the expanded portion 56 engaged with the hole 44 The handle 102 of the tool 100 has a conical, relatively truncated end part 106 which is dimensioned so as to extend to the base of the hole 60 when the part 56 is assembled on the plate 30, so that the handle can be pushed or forced and driven so

  Tubular dartie 56 out of the hole 44 This facilitates the

  tege of a set of worn stone when a new set

of stone must be mounted.

  Figs 20 and 21 illustrate yet another way of mounting a stone assembly, although in this case a two stone assembly 110 similar to the assembly 24 A of Figs 13 and 14 is mounted on a stone carrier plate 112 principal The plate 112 of the stone holder has one or more holes, like the hole 114 and the latter is cylindrical over part of its length and

  conical on at least one other part, as in 116.

  The stone assembly 110 has a tubular portion 118 with a cylindrical outer surface to align and fit into the hole 114, and the portion 118 has an cylindrical inner surface 120 over most of its length, but constricted or tapered at 122 so that its smallest diameter is close to the free end of the part 118 This means that the wall of the tubular part 118 is thicker at 123 than over the rest of its length To fix the assembly of stone 110 on the plate 112 of the main stone holder, the parts are assembled with the parts, 118 penetrating into the respective holes 114, and then a tool 124 which comprises a threaded end part 126 and a handle, for example the handle 128 at right angles, is positioned as shown in Fig 20 In this position, the tool 124 is rotated to tap in the hole and to cut and form a thread therein, thereby expanding the part 118 outwards During This time, the tool also taps its passage through the constricted or thickened end portion 123 so that the latter expands outward more than the rest

  from part 118 This moves part 123 outwards

  laughing in abutment against the conical interior surface 116 of the

  hole 114, thus forming a positive engagement with it.

  This engagement prevents the stones from loosening and separating. It would also be possible to provide a shoulder in the hole 114 near its free end.

  for the same purpose, but a conical engagement is general-

  preferred because it is then easier to separate the

  parts for the replacement of a worn stone set.

  According to Fig 21, the hole 120 is widened at 130, so that the thread 126 of the tool begins to cut a

  net in part 118, halfway to the support piece.

  The widening part 130 of the hole has the function of guiding the tool 124, which can be an advantage in certain cases, and can also avoid cont-airints of the body of the body of the oil Se 1 on the Fiq 21 , threaded part 126 of

  the tool is shown after it has fully tapped-

  n.ent its way into the hole 120 It appears aue when the tool passes through the throttled part 123, it meets the strongest resistance to rotation because the diameter of the hole is smaller and the thickness of the metal is greater But , when the tool leaves the constricted part 126, the pressure necessary to continue turning it abruptly decreases and there is little or no other expansion of the part 123 This means that the maximum possible expansion of the part 123 can be controlled exactly and limited at will, and without allowing the operator to apply excessive force which could

  break or split the tubular part 118.

  The main advantage of the embodiments shown in Figs 19 to 21 is that the fixing of the stone assembly on the main stone holder can be done without

  use screws or other threaded parts left in the

  Another advantage of the embodiments of Figs 20 and 21 is that the fixing can be done without requiring that the whole assembly be removed from the head on which it is mounted. This last advantage can represent a substantial saving in the time necessary to replace the stones. on a head The same characteristics can also apply to an assembly on which is mounted a single stone or a row of stones But in the case of an assembly with a single stone, it may be necessary that the tubular parts are slightly offset so that they are not positioned directly below

lapping stone.

  To disassemble the sets of stone replaced

  cables shown in Figs 20 and 21 of the main stone holder, one or more separate holes like the hole 132 in Fig 22 can be provided in the assembly 110 in positions spaced from each other ol "of the tubular parts 118 The holes 132 are preferably smooth holes so that the disassembly tool 124 can tc) iller its own thread, although they can be tapped at will The threaded end portion 126 of the tool 124 is screwed in the holes 132 and, when the tool 124 is turned in these holes, its end comes up against the stone holder 112, so that an additional rotation applies a force against the latter, in a direction which tends to spread the parts apart one of the other One of these holes 132 can be positioned close to each of the tubular parts 118 although in certain cases, a single hole provided in the center may be sufficient The same means can be used to separate any of the assemblies of stone described above swings from their slingshot,

  but this is generally not necessary in reali-

  sations in which the assembly is first removed from the lapping head before a new stone assembly is mounted This is so because when the assembly is disassembled

  from the head, access to the tubular parts 56 is easy.

  Different embodiments of a new lapping stone mounting device have been illustrated and described above, comprising a new stone assembly and a new assembly device for this assembly on a main stone holder, meeting all the objects

  and expected benefits But it is obvious that many

  serious modifications of the variants, as well as other applications of this device are possible without leaving the

  nor the spirit of the invention.

ú 515087

Claims (24)

  1 mounting device for lapping stones and the like, characterized in that it comprises a support structure (22) comnrenant a plate (30) with opposite surfaces and spaced openings (44) which pass through it, a set of stone (24) intended to be mounted on the plate, comprising a support piece (26) with opposite surfaces, a first of which is intended to be placed in surface contact on a first of the opposite surfaces of the plate, a lapping stone ( 28) mounted 7 on a second opposite surface of the support piece, spaced tubular parts (56) formed on said second surface of the support piece, in positions such that they are aligned and can be introduced into the respective spaced openings in the plate, and a threaded fastener (62), comprising a threaded portion to be screwed into each respective tubular portion when positioned to enter one of the spacing openings of the plate, so that the threaded parts of the fastening parts cut a thread in the tubular parts and simultaneously expand these tubular parts towards the outside in the respective openings of the plate to form a   tight engagement with this plate.   2 Mounting device according to reference-   tion 1, characterized in that said support piece 26 is   made of a softer metal than said plate (30).   3 mounting device according to claim 1, characterized in that the tubular parts (56) extend from ends connected to the support piece to opposite free ends, notches (28) axially directed being formed in the tubular parts and penetrating therefrom from the free ends to facilitate radial expansion when the   threaded fasteners are tightened there.   4 mounting device according to claim 1, characterized in that the tubular parts (56) extend outward from the support piece A 15087   (26) on which they are fixed at a distance which is less than the distance between the opposite surfaces of the plate. Mounting device according to claim 1, characterized in that the support piece is made of cast zinc. 6 A mounting device according to claim 1, characterized in that the support piece comprises a flange (64) of which it is integral, which extends up against at least one side of the plate on which it is fixed. 7 mounting device according to claim 1, characterized in that the support piece (26) has a peripheral flange (64) directed outwards around the lateral edges of the plate when the stone assembly got on it.   8 mounting device according to claim 1, characterized in that the surface (48) on which the stone is mounted makes an acute angle with the surface   opposite which is adjacent to the plate (30).   9 mounting device according to claim 8, characterized in that it comprises a flange (50) on the support piece (26) extending along a lateral edge of the surface of this support piece, along the side of the lapping stone attached to it.   Mounting device according to claim 1, characterized in that the threads of the threaded parts of the threaded fasteners (62) are conical, their diameter being larger near one end than the other. 11 Support assembly on a workpiece,   intended to be mounted on a mandrel or the like, available   sitive characterized in that it comprises a support structure (22) comprising a plate (30) with surfaces ú 5 '53587   ci - '= g; & et d-ux c C-'mailllres (32), (34) espac Ccs, diri-   * 'r - "s' exytriieur, extending from a first O c'J: - ces év 1, di: openings space L-es (4) aer-an dit, laq: e Bntre 1 opposite surfaces and an abrasive handle (24) - nted on said plate, said   rsóbl 1 abrasive cc - nant a support icec (26) ccmrpor-   tat cdes surfaces o, cs -es of which a first is mounted cuntre the second of the orposed surfaces of the plate, an abrasive niece (26): oe on a second surface cp Dosce de la roièc'e dia ia "nièce d ' a Dumi comprising two tubular parts (56) spaced apart from which it is integral, in spaced positions such that they align with the openings spaced from the plate, and threaded fasteners (62) each having a head connected to a threaded part to be screwed into a respective one   tubular parts so that the tubular parts   laires expand radially outward when engaged   with the plate when the threaded parts are there blocked by screwing.   12 The assembly of claim 11, character-   risé in that the tubular parts (56) of the support piece (26) extend outwardly by a distance less than the distance between the opposing surfaces of the plate (30), each of said tubular parts comprising a first end connected to the support piece and an opposite free end and at least:   groove (58) penetrating into each of the tubular parts   laires from its free end to facilitate radial expansion when the threaded parts are there tight.   13 An assembly according to claim 11, characterized in that each of the tubular parts (56) has an opening for receiving said respective threaded part (62), said openings extending   eh part through the support piece (26).   14 assembly according to claim (11), characterized in that it comprises a peripheral flange (64) extending from the support piece to surround the plate (30) when the support piece is fixed on her.   An assembly according to claim 11, charac-   terized in that the opposite surfaces (46), (48) of the support piece form an acute angle. 16 Assembly according to claim (11), characterized in that the support piece (26) is made of cast zinc.   17 The assembly of claim 11, charac-   terized in that it comprises a stone (28) fixed by an adhesive on the support piece, on the face opposite to the plate (30).   18 Mounting device for lapping stones and the like, characterized in that it comprises a support structure (22) comprising a plate (30) with opposite surfaces and two spaced openings (44) which pass through it, a set of stones (24 A) intended to be mounted on the plate and comprising a support piece (26) with opposite surfaces, a first of which is intended to be placed against a first of the surfaces of the plate, at least one stone (28 A) mounted on the second opposite surface of the support piece, spaced tubular projecting portions (56 A) formed on said first surface of the support piece in   positions as they can line up and be intro   picks in the respective spaced openings of the   plate, said plate having a lateral edge extending   dant around its periphery between the opposed surfaces and said support piece having a peripheral rim (64) which extends around the peripheral lateral edge of   the plate, and a threaded fixing piece (621   nant a threaded part intended to be screwed into each   tubular projecting part which is positioned in extension   dant in one of the spaced openings of the plate, so that the threaded parts of the fixing pieces cut a net in the tubular projecting parts and simultaneously expand these tubular parts towards 2515087 2 o '   the exterior 'in the plate openings.   19 Mounting device according to the claim   tion 18, characterized in that corresponding parts   dantes of the peripheral lateral edge part of the plate and the peripheral rim of the support piece are inclined to bear against each other when the stone assembly is positioned on the plate, this support delimiting a space between plate and support piece.   20 Mounting device according to the claim   tion 19, characterized in that the spaced tubular parts (56) have a dimension A smaller than that of the   corresponding openings (44) of the plate.   21 Mounting device as claimed   cation 18, characterized in that two lapping stones (28 A), (28 B) are mounted spaced apart and parallel to each other on said second opposite surface of the part, support (26) -   22 Mounting device as claimed   cation 18, characterized in that two parallel and spaced racks (32), (34) are fixed on the plate   and are directed outwards.   23 Mounting device for lapping stones and the like, characterized in that it comprises a support structure (22) comprising a plate (112) with opposite surfaces and spaced openings which pass through it, a set of stones (24) intended to be mounted on the plate and comprising a support piece (26) with opposite surfaces, a first of which is intended to be placed in contact with a first of the opposite surfaces of the plate, at least one lapping stone (28) mounted on the second opposite surface of the support stone, spaced tubular portions (56) formed on said second opposite surface of the support piece in positions such that they are aligned and can be inserted into the spaced openings 21 2515087   respective of the plate, the openings of the plate having a portion of larger diameter opposite to   said first surface and the tubular parts spa-   cées comprising openings which pass through them as well as the support part, said openings in the tubular parts comprising a part of smaller diameter near their free end and a part comprising a threaded part intended to be screwed into said tubular parts through said piece   support to cut a net in the tubular parts   and simultaneously expand them outward   support against the respective openings in the plate.   24 Mounting device as claimed   cation 23, characterized in that the threaded part of the threaded part (62) penetrates into the openings of the   tubular part through the support piece.   Mounting device as claimed   cation 23, characterized in that two spaced lapping stones (28 A), (28 B) are mounted on the support piece, spaced from each other on the side opposite to the tubular parts.   26 Mounting device as claimed   cation 23, characterized in that it comprises an opening (132) formed in the support piece in a position spaced from the tubular parts (56), to receive a threaded piece used to separate the support piece from the plaque.   27 Mounting device as claimed   cation 26, characterized in that the opening (132) formed   in the support piece is tapped.   28 Mounting device for lapping stones and the like, characterized in that it comprises a support structure (22) comprising a plate (30) with opposite surfaces and at least one opening (44) passing through it, an assembly of stone (24) intended to be mounted on the plate and comprising a support piece (26) with opposite surfaces, a first of which is intended to be placed in contact with a first of the opposite surfaces of the plate, a stone to be ground (28) mounted on the second opposite surface of the support piece, tubular parts (56) the number of which corresponds to that of the openings in the plate, formed on said first opposite surface of the support piece and arranged to line up and be inserted into the corresponding number of plate openings,   and a device that can be inserted into each of the   said tubular parts to expand it radially towards-   the exterior in engagement with the corresponding openings dantes in the plate.   29 Mounting device as claimed   cation 28, characterized in that the device which can be inserted into the tubular parts (56) consists into a grub screw (80).   -Mounting device according to the resale-   cation (28), characterized in that the device which can be inserted into the tubular parts (56) consists   into a ball (94) whose diameter is slightly greater than   laughing at the inside diameter of the tubular parts.   31 Mounting device as claimed   cation 28, characterized in that the openings (44) in the plate (30) have milled parts which extend inside the opposite of the support piece (26), the device being able to be inserted into the tubular parts comprising a threaded part with a countersunk head (88) which adjusts to the milled surface   of the corresponding opening of the plate.