US2569592A - Apparatus for polishing precious stones - Google Patents

Description

Oct. 2, 1951 Q WEST 2,569,592

APPARATUS FOR POLISHING PRECIOUS STONES Filed Nov. 1, 1948 3 Sheets-Sheet 1 Oct. 2, 1951 3, WEST APPARATUS FOR POLISHING PRECIOUS STONES 5 Sheets-Sheet 2 Filed Nov. 1,1948

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@WM MvW Patented Oct. 2, 1951 APPARATU FOR POLISHING PRECIOUS STONES Charles West, London, England, assignor to Henry Oliver and Lewi Stone, both of London,

England Application November 1, 1948, Serial No. 57,685 In GreatBritain November 4, 1947 This invention relates to apparatus for polishing precious stones particularly diamonds, and to apparatus of the kind in which the dop for holding the stone is mounted in a head at the end of an arm or tang, which latter is so supported at its end remote from the head as to permit the head to swing downwardly under gravity so that the stone engages the flat face of a rotating polishing element and also permits the dop to be moved towards and away from the centre of rotation of the polishing member.

According to this invention an apparatus for polishing precious stones of the kind referred to comprises a flat faced member having its face parallel with thatof the polishing element, an arm, a head at one end of the arm adapted to carry a dop, a fulcrum on said arm disposed away from the head and slideably engaging the face of said fiat faced member permitting the arm to swing in an up and down direction, a stop or support rigidly fixed to said flat faced member and arranged to underlie said arm.

Means may be provided for securing said fiat faced member to a bench which means permit adjustment of said member relatively to the bench to bring the flat face parallel with the polishing face.

For example the fiat faced member comprises a metal plate and clamping bolts extending through holes in said plate and through plugs adjustably mounted in said bench, the heads of which plugs support said plate.

The aforesaid head embodies means for adjusting the position of the dop in an up and down direction. With this arrangement the support is initially adjusted so that the arm, when resting upon it, is parallel with the surface of 8 Claims. (Cl. 51'229)' the polishing disc, and the head is then adjusted I so that when the stone is resting on the disc the arm is raised from the stop by an amount corresponding to the amount of cut required. Polishing will thus cease when the arm contacts with the stop.

The arm may be provided with two downwardly extending legs spaced apart in a direction across the length of the arm, which legs are arranged to rock on said support, and one of said locating faces is arranged to abut the side of one of said legs, while the other locating face is arranged to abut the side of the arm adjacent said stop.

The latter locating face may be provided by a pillar on which said stop is adjustably mounted, which pillar is carried by'said support.

A warning device may be arranged to be operated by said arm coming into contact with said stop. For example a member resiliently mounted on said stop is arranged to be moved by the arm when approaching the stop so as to close contacts in a circuit with a warning device and with a source of supply. f

The warning device may comprise an electric light mounted on said support. H

The resiliently mounted member may comprise a lever, one end of which is arranged to be engaged by said arm and the other end of which may comprise one of a pair of electric contacts in circuit with the warning device, and a spring may be arranged to urge the bell-crank lever to a limiting position in which the first said limb is slightly proud of said stop.

The aforesaid head may comprise a bearing in which may be rotated the stem of a bracket carrying the dop and the associated indexing mechanism for bringing different facets into a polishing position, which bearing is adjustable in an up and down direction. One of the purposes of this bearing is to enable the face of the stone in contact with the disc to be brought into a position in which the grain of the stone is appropriately disposed in relation to the direction of rotation of the disc. It is important that the axis of this bearing shall be normal to the grinding surface, otherwise the adjustment of the bracket about said axis will adversely effect the setting of the facet being ground.

In order to enable the axis of the bearing to be set accurately at right angles to the surface of the grinding disc the aforesaid bearing member is mounted universally in said head so as to permit a limited pivotal adjustment in any direction, and means are provided for clamping the bearing member in an appropriate position.

The following is a description of one form of diamond-polishing device according to this invention, reference being made to the accompanying drawings, in which:

Figure 1 is a perspective view of the mounting for supporting the diamond holder or dop;

Figure 2 is a section through the head which receives the dop; v Figure 3 is a view looking from the right of Figure 1, showing the warning device;

Figures 4 and 5 are side elevations of the means for applying a load to the arm, and Figure 6 is a section through loading device when in an operative position.

of which legs are provided with projections I3;

which may rock on a metal supportingplate. I4. having holes I5 whereby it maybe attached firmly to a bench. One of the legs is arranged to abut against an upstanding ledge I6 onthesupporting plate I I. The side-of thearm II remote from said ledge is arranged to abut against a pillar II carried by an arm I81 secured to thesupporting plate by set screws I9. The-pillar: II

carries a stop which underlies the armand is adjustable in an up-and-down direction, and this pillar is held in the adjusted positions by a grubscrew; 21: i

As will be'seen from Figure 3-, an-endiface of the stopZIljhas-pivotally mounted upon ita lever armIZWhichis'urgedbyia wire spring 23 against a' stoppin'24" in whichg-position'a pointedwend 25 of the lever arm extends a short. distanceabove the top face of the stop 20. The lower end'oflthe lever arm 22" is arranged opposite'an adjustable electric contact 26' on an arm 21 carried by an insulatingblock ZB'SBCIIIGd'tO the part I8. The lever arm inengagingthe contact 26 establishes a'circuit" in which a warning lamp 29.is energised bysource of supply 30;

Aswillbe seen from Figure 2, the end of" the arm II is'proyided with a cup-shaped recess 3| having an aperture" 3.2" at' the bottom" thereof; The headis providedwith'a'spherical portion33 which-rests in said recess and with a flange 34 whichoverlies the'arm'. The flange is provided witha'numb'erof-threaded'holes-engaged by setscrews 35-which-extend through thearm, whereby the spherical 'part 'of thebody may be clamped firmly in therecess.

Thetubular bearing member I0- extends througha -bore in the-head so as-tobe a good sliding-fit in the lower part: of the bore 36, which bearing member is. provided: with. ana external key-way 3i-whichiscengaged'by. aikey 38lfixed in the head; The upper part; of the bore is enlarged atl39iand the. upper part of .thebearing member. is externally threaded-1 at; 430; This threaded part is, encircled by; a nut having a flan e-54']; 2t11d3a';b0SSE4'2; WhlCh latter is: a rotating fitjimthe enlarged bore. The boss is provided with-a.circumferential'groove of rectangular section which, accommodates two parts-of a split sleeve 43; each'of which is providedwith aconica l depression,4z4 which may. be engagedby the pointedcendiofra grub-screw 45, in the head, so as to draw the split sleeves downwardly, and with them? thenut sothat. the flange. rests snugly against the topl of the head, thus. preventing blacklash.

'Iihe plate- It may; be; mounted on the same bench;58 as-the'scathe 46;and it is importantthat the-faceofitheplate.shall be strictly parallel to the face of the scathe. Means are therefore providedtfor-adjusting'the.position of the plate in relation to the bench.v Thesemeans may comllrisezaznutlfiiinset in the bench beneath each corner of the plate, .each. of which nuts receives anrexternally threadedhollow plug 64' having a domed head 65, on,which.theplate.rests.. Bolts 4 69 extend through the hollow plugs and bench and are provided with clamping nuts 66.

In setting up the device, the plugs 64 are adjusted to bring the plate accurately parallel to the surface of the scathe and the bolts tightened so as firmly toclamp the plate-to the bore. The stop2ll is. adjusted to sucha position that when the arm I I is resting upon it, the axis of the bearing member ID is accurately at right-angles to the surface of the scathe by which the diamond-isgroundj which scathe is shown in chain lines at 46 in Figure 1, in this position the diamond is resting onthe scathe. The amount by which the'diamondis to be ground may then be set by twistingwthe' flange 4| of the nut which may be' graduated at 41 on its upper surface,

I which graduation co-operates with a pointer 48 on'the arm. The arm is thus lifted a short distance from the stop 20, and the lever arm 22 is brought away from the'contact 26 by the spring 23. Grinding then. commences. and the; arm gradually. lowers, and when the predetermined amount of grinding hasbeen effected, the arm I]: will have. swung the lever ZZinto engagement with the contact-25f and the warning light 29 is thenbrought into operation. With this arrangement when the feet I3.are moved over the accurately-groundface of the plate l i'the axis of the bearing member It is maintained accurately at right-angles to the scathe for all positions of the arm; While the arm is prevented from lateral movement by the ledge I6 and pillar I'I which'movement might otherwise'take place due to the rotation of the scathe.

The-arm II may be loaded either by placing weights on topofit, or it may be more accurately loaded by means of a loading arm'49 along which amass fillmay be adjusted; The loading arm is pivoted at 5I'and' has pivotally secured'at 54'on either side thereof, two upwardly-extending members" 52, 53a The member 53 1s provided with apeg. 55: which: when the two members have been swung into the position Figure lzmay; betpushedinwardly-to overlie a ledge 58secured to the-undersideof the arm II, the peg may; be retainedin the operative and inoperative posi-- tions by a springdetent 61-. The peg is provided with a manipulating head 51. The peg: in its outermost position isarranged to be clear. of the ledge56'.

The lower endv of'themember- 52 is provided with'a cammingpiece 5Swhich engages an abutment'59on the part- I8 whereby the loading arm. '39 maybe raised andthe peg brought above the ledge'56 as shown in Figure 4. In this position, when the peg is in its outermost position, theheadSI lies in the path of movement of the upper portion of the member 52. As soon as'the peg has been pushed inwardly, the member 52- maybe swung into a position in which the camming member 58iis no longer in contact with thea-b'utment 59-whereupon the-load is transferred to the-arm I I'. The member 52 is provided with amanipulating tag-til, and a locating piece 6I for the other member 53, which enables the two members 52 and 53to" swing. together so as to bringgthe'peg entirely-clear of the arm II;

The .membenIBiis provided with recesses 62 for. receiving'the stones before or after grinding and; therecesses may; be covered by. a plate 63 ar-' ranged-to clipon to the member, I8;

I- claim:

1. An: apparatus for use with a flat faced polishing element for polishing precious stones: which apparatus comprises a flat-faced member,

adjustable securing means for holding that member on a bench whereby its face may be brought parallel with the face of the polishing element, an arm, a head at one end of the arm, a dop carried by said head, a fulcrum on said arm disposed away from the head and slidably engaging the face of said fiat-faced member permitting the arm to swing in an up-and-down direction, a support rigidly fixed to said fiat-faced member and having a part underlying said arm.

2. An apparatus for use with a flat-faced polishing element for polishing precious stones which apparatus comprises a bench, a number of plugs adjustable in relation to the surface of the bench, a flat metal plate resting on said plugs which plate and plugs have registering holes, clamping bolts extending through said holes, an arm, a head at one end of the arm, a dop carried by said head, a fulcrum on said arm disposed away from the head and slidably engaging the face of said fiat-faced member permitting the arm to swing in an up-and-down direction, a support rigidly fixed to said fiat-faced member and having a part underlying said arm.

3. An apparatus for use with a fiat-faced polishing element for polishing precious stones which apparatus comprises a fiat-faced member, adjustable securing means for holding that member on a bench whereby its face may be brought parallel with the face of the polishing element, an arm, a head at one end of the arm, a dop carried by said head, a fulcrum on said arm disposed away from the head and slidably engaging the face of said fiat-faced member permitting the arm to swing in an up-and-down direction, a support rigidly fixed to said flatfaced member, a part underlying said arm and adjustable in an up-and-down direction on said support.

4. An apparatus for use with a flat-faced polishing element for polishing precious stones, which apparatus comprises a fiat-faced member, adjustable securing means for holding that member on a bench whereby its face may be brought parallel with the face of the polishing element, an arm, a head carried at one end of the arm, means for adjusting said head in an upand-down direction relatively to said arm, a dop carried by said head, a fulcrum on said arm disposed away from the head and slidably engaging the face of said fiat-faced member permitting the arm to swing in an up-and-down direction, a support rigidly fixed to said flat-faced membeer and having a part underlying said arm.

5. An apparatus for use with a flat-faced polishing element for polishing precious stones which apparatus comprises a fiat-faced member, adjustable securing means for holding that member on a bench whereby its face may be brought parallel with the face of the polishing element, an arm, a head at one end of the arm, a dop carried by said head, a fulcrum on said arm disposed away from the head and slidably engaging the face of said flat-faced member permitting the arm to swing in an up-and-down direction, a pillar rigidly fixed to the fiat-faced member on one side of the arm, a support on said pillar underlying said arm, an upstanding ledge on the fiat-faced member on the other side of said arm, which ledge and pillar are adapted to constrain said arm to move rectilinearly towards and away from said polishing element.

6. An apparatus for use with a fiat-faced polishing element for polishing precious stones which apparatus comprises a flat faced member, adjustable securing means for holding that member on a bench whereby its face may be brought parallel with the face of the polishing element, an arm, a head at one end of said arm, a mounting for said head adapted to permit angular adjustment of the head about a vertical axis, a dop carried by said head, a fulcrum on said arm disposed away from said head and slidably engaging the face of said fiat faced member permitting the arm to swing in an up-and-down direction, a support rigidly fixed to said fiat-faced member and having a part underlying said arm.

7. An apparatus for use with a fiat-faced polishing element for polishing precious stones which apparatus comprises a fiat faced member, adjustable securing means for holding that member on a bench whereby its face may be brought parallel with the face of the polishing element, an arm, a head at one end of the arm, a dop carried by said head, a fulcrum on said arm disposed away from the head and slidably engaging the face of said fiat-faced member permitting the arm to swing in an up-and-down direction, a support rigidly fixed to said fiat-faced member and having a part underlying the said arm, a warning device, and a transmission between the arm and support adapted to magnify the movement of the arm and to actuate the warning device when the arm contacts with the underlying part of the support on which it freely rests.

'8. An apparatus for use with a fiat-faced polishing element for polishing precious stones which apparatus comprises a flat-faced member, adjustable securing means for polishing that member on a bench whereby the face may be brought parallel with the face of the polishing element, an arm, a head at one end of the arm, a dop carried by said head, a fulcrum on said arm disposed away from the head and slidably engaging the face of said flat-faced member permitting the arm to swing in an up-and-down direction, a support rigidly fixed to said flatfaced member and having a part underlying said arm, a lever pivotally mounted on said fiat-faced member, a mass adjustable along said lever, an abutment on the lever overlying a part of the arm and cam means for moving the lever and abutment slowly into the path of movement of the arm.

CHARLES WEST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 802,368 Coleman Oct. 24, 1905 1,103,698 Soetens July 14, 1914 1,166,843 Loesser Jan. 4, 1916 1,269,002 Ries June 11, 1918 1,284,109 Hunt Nov. 5, 1918 1,583,963 Donaldson May 11, 1926 2,382,099 Rothauser Aug. 14, 1945 2,391,979 Kershaw Jan. 1, 1946 2,423,826 Cardone et a1 July 15, 1947 2,429,961 Rakowitzky Oct. 28, 1947 FOREIGN PATENTS Number Country Date 564,074 Great Britain Apr. 9, 1943 566,334 Great Britain June 7, 1943

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