US1862704A - Tile grinding machine - Google Patents

Description

June 14, 1932, T Q R U T AL 1,862,704

TILE GRINDING MACHINE Filed Oct. 51, 1927' 4 Sheets-Sheet l J1me T. c PROUTY ET AL 1,362,704

TILE GRINDING MACHINE Filed Oct. 151,- 1927 4 Sheets-$heet 2 g y NVENTORS *w "a $1? June 14, 1932. c T ET 1,862,704

TILE GRINDING MACHINE Filed Oct. 31, 1927 4 Sheets-Sheet 3 f5 INVE 1T R5 BY 3 ATTORN EY June 14, 1932.

T. C. PROUTY ET AL TTLE GRINDING MACHINE Filed Oct. 51 1927 4 Sheets-Sheet 4 ATTORNEY Patented June 14, 1932 UNITED STATES PATENT OFFICE THEODORE C. PROUTY AND WILLIS 0. PROU'IY, OF HERMOSA BEACH, CALIFORNIA, AS-

; SIGNORS TO AMERICAN ENCAUSTIC TILING COMPANY, LTD., 01? NEW YORK, N. Y., A

CORPORATION OF NEW YORK TILE GRINDING MACHINE Application filed October 31, 1927. Serial No. 230,112.

Our invention is a tile grinding machine, the objects of which are, first, to finish with mathematical exactness the edges of tiles, and, second, to provide large capacity for carrying tiles to the end that the products may be finished economically and with minimum hand labor.

In the tile industry the product found 1n the markethas been characterized by variations in dimensions, and by distortion, more or less, due to contraction and warpage of the material following the firing operation at high temperatures prevailing in bisque kilns. Furthermore, the bisque body of ordinary floor and wall tiles has been composed heretofore of materials which do not lend themselves to reduction by grinding to accurate dimensions, at least without undue and excess wear on the grinding materials.

In our Patent No. 1,628,910 for Ceramic process and product, patented May 17, 1927, we have disclosed a bisque body and a process of making the same, wherein the contraction and distortion of the material is minimized at the firing stage and subsequently thereto, said bisque comprising a material or combination of materials susceptible to grinding with facility for reduction to accurate dimensions.

The machine of our present invention is intended for use, more particularly, on the bisque constituting the product resulting from the patented invention, although it will be understood that we do not limit or confine the use of said machine to the production of the specified product.

According'to our invention the machine, generally speaking, embodies a revolvable carrier and a plurality of rotary grinding members so related one to the other that the work is presented on the travel of the carrier successively to the grinding members.

The carrier is equipped with a number of work holders for retaining the material (tiles) to be treated in fixed position radially to the axis of rotation of said carrier, and in a determined relation to the rotary grinding members, the axis of rotation of which members are parallel, or substantially parallel, to the axis of rotation of said carrier. The

work holders are constructed for the reception of a group or assembly of tiles, in contradistinction to individual holders for single tiles, and in a practical embodiment of this part of our invention the separate holders for the massed tiles are each constructed with clamping members for contact with the two outermost tiles of the assembly, one of said members being movable relatively to the other member. Said" movable clamp member is carried by a lever constituting one element of a holder actuating mechanism adapted for operation with facility by the attendant Workman, to the end that the work holder may be controlled or operated to instantly release the assembled tiles by a simple movement of one of the parts and which holder-actuating mechanism is spring controlled for the application of pressure to the massed tile in a way to retain said tile assembly firmly and securely againstany tendency to become dislodged or displaced under the action of the grinding members, or either-of them.

Other functions and advantages of the invention will appear from the following description taken in connection with the accompanying drawings, wherein- Figure 1 is a plan view of our tile grinding machine, with parts broken away for the illustration of the carrier driving mechanism.

Figure 2 is a view partly in side elevation and partly in vertical section for the illustration in side elevation of the carrier driving mechanism.

Figure 3 is a vertical section showing in detail one of the work holders, parts being in elevation, the dotted lines showing the released position of the holder actuating mechanism.

Figure 4: is an enlarged sectional elevation of one of the work holders illustrating a group or assembly of tiles clamped fixedly in position by and between the clamp members, the holder actuating means being shown in the operating position.

Figure 5 is a front elevation of the mechanism of Figure 4.

Figure 6 is an enlarged view of one of the grinding members, illustrating in vertical section and in elevation the means for mounting said grinding member to have an operative and adjustable relation to the rotary carrier.

Figure 7 shows view of a tile in side elevation and 'n perspective, adapted to be ground with bevZled edges by the machine of this invention, and

Figure 8 is a sectional elevation of beveled edged tiles installed on a wall surface.

A designates the rotary carrier, and B, C, a plurality of rotary grinding members in operative relation to groups or masses of tiles supported fixedly on said carrier for rotation therewith.

The carrier is, generally speaking, in the form of a substantially open ring supported in a horizontal position for rotation on a vertical axis. The ring-like carrier is formed by a vertical Wall or web, a, the bottom portion of which is flared and enlarged at (1' (Figures 2 and 4) to produce a substantial construction adapted for co-operation with ball bearings, d. The carrier may be said to be of massiveformation to produce the stability requisite for the movement of grouped or massed tiles in accurate relation to the grinding members, but obviously, the detailed construction shown in the drawings may be modified by a skilled constructor. As shown, the carrier rests upon a circular bed, D, the top edge of which is flanged at d to produce a widened bearing surface for the reception of a ball race, D, in the channel d of which is received the bearing balls d, the latter entering a corresponding channel (Z provided in the enlarged section a of the rotary carrier ring. As shown, the lower edge portion a is flanged at d to form a groove in which is received the ball race D, said flanges constituting a housing for the upper edge of the annular base D for the exclusion of dust and dirt from the ball race and the ball bearings.

Positioned interiorly of the carrier and fixedly attached thereto is a ring gear, 6, with which meshes a driving worm gear 6 provided on a short horizontal worm shaft, E see Figure 1, the latter being within the carrier and its base and being appropriately supported in bearings provided by a plurality of posts, 9 Fi ures 1 and 2. The worm shaft is driven from a motor, F, supported within the annular bed, D, on a platform, 7, which aifords the support, also, for the posts, e The motor shaft drives a belt 7 which imparts motion to a speed reduction gear, F, of any suitable type, said reduction gear 1mparting motion to a belt, f operating to drive the worm shaft E. The carrier 1s motor driven for presenting the work holders thereon one after the other to the grinding members, and said carrier moves at relatively slow speed to afford an appreciable period of time for the action of said grinding members upon the group or assembly of tiles within each work holder.

Any desired number of work holders are provided on the carrier A, the drawing showing a carrier of a capacity for holding about forty (40) tile assemblies, one tile assembly in each work holder. The work holders are of identical construction and operation, and each work holder is adapted for manual control with ease and facility to the end that the tile assembly may be introduced quickly into the work holder, and the latter operated manually to firmly clamp the tile assembly and to retain such clamping engagement automatically during the period required for the presentation of the tile assembly to the grinding members, and for the abrasive action of said grinding members upon the edges of the tile assembly. The work holder is operated manually for releasing the tile assembly with the same facility with which it is clamped, and the clamping elements of said work holder are so related that the tile assembly when unclamped is accessible with ease and freedom to the end that the tile assembly as a unit may be removed, or it may be reversed or changed in position within the work holder as may be demanded by the service.

Each work holder and its actuating means is of novel construction, and is described as follows :On the exterior vertical face of the annular carrier A is positioned a bracket G having a bed piece g, said bracket standing vertically with respect to the carrier wall a,

and being fixedly attached thereto, as by through-bolts g. The bracket G has a member extending upwardly from the bed 5 and attached to the upstanding member 5 and to the bed 9, are liners H, H, the liners H being fastened by screws h to the upstanding bracket member 9 whereas the liners H are fastened by other screws h to the bracket bed 9, see Figure 4c. The liners H, H, are at an angle, desirably a right angle, one to the other, and the tile assembly is adapted to be deposited by the attendant workman into contact with the faces of said liners, so that the vertical face of one end tile of the assembly rests against the vertically positioned liners H, whereas all the individual tiles in the assembly rest at their bottom edges upon the horizontal liners H. In the example shown in Figure 4, the active faces of the liners H are at an angle other than a right angle to the corresponding faces of liners H, so as to slightly tilt or cant the individual tiles of the assembly resting upon the tile holder, the effect of which is to present the upper edges of the individual tiles in such relation to the plane of the abrasive surface on the grinding members that in the act of trimming the tiles there results a slight bevel on the edge of the tile, see Figure 7, whereby the tiles may be assembled, as in Figure 8, with the edges of one tile in contact with the edges of other tiles, insuring speed and accuracy in installing or setting the tiles on a wall or other surface.

Ordinarily, however, the liners H, H, are influence of aspring, J. The stud or pin K arranged for the active faces to be at a right is fixedly attached to or forms a part of angle, and thus the tiles of the assembly are lever member K, and clamp lever J is norpositioned in a determined accurate relation mally in contact with said stud or pin K by to the grinding members without imposing the energy of the spring J in the active posiupon the attendant workman the necessity tion of parts J, K, see Figures 3 and 4, but for exercising undue care or skill in depositwhen the lever member K is raised up to the ing the tile assembly in the work holder, it inactive position indicated by dotted lines in being required only that the tiles be assem- Figure 3, then the tension of a spring M on bled for their edges to register and then the the thrust rod is relaxed, leaving substanassembled tiles are simply dropped into contially free the clamp lever J and the clamp tact with the liners H, H. head I for the easy introduction or removal The upstanding member, 9 of the bracket of the tile assembly with respect to the work G, constitutes a fixed clamp member for the holder. The spring J is shown as anchored tile assembly, and cooperating with said fixed at one end to a fixed plate j on the bracket G, member is a movable member I, shown as a and as attached at its other end to the lower substantial plate or head, mounted on the part of the clamp lever, the function of said I upper part of a clamp lever J for universal spring being to quickly move the lever J and V as movement, and retained normally in alined the clamp head I to the out-of-service position relation to the fixed clamp member by guide when the hand lever K is raised to the dotted members 2'. The movable clamp member I line position of Figure 3. The thrust rod L is supported by a bolt 2', the latter having it extends inwardly of the annular carrier A rounded head i see dotted lines in Figure for a suitable distance, and on the inner ex-- 4. socketed in the outer face of said clamp tremity of said rod is loosely fitted a crossmember. The threaded shank of the bolt 2" head, m, the end portions of which are at is screwed into a hole tapped in the upper tached to parallel guide rods M fixed in the part of lever J, and is set in adjusted position annular carrier A, Figure 4. These fixed by a nut 2' the described construction Inakguide rods and the crosshead aiiord station'- ing provision for the adjustment of clamp ary means for seating a strong coiled spring member I with respect to the fixed clamp M, the latter being fitted loosely on the thrust member. The universal connection between rod L and said spring acting to exert tension the movable clamp member and its supportto the thrust rod through the agency of a ing bolt permits a free movement of the clamp collar of pinned fast at m to the thrust rod, member and enables it to adapt or adjust it- Figure 3. The slot 7' extends for a desired self to the tile assembly, but said clamp memdistance in the clamp lever toward the pivotal ber cannot turn out of place, for the reason joint 7', and the hand lever K is free to slide that the guide pins 2' are attached to the clamp within the slot 9' on the up and down movemember and loosely embrace the clamp ment of said lever K with respect to the clamp lever, lever. With the hand lever K in the inclined As shown,the clamp lever is positioned subraised position indicated by dotted lines in stantially vertically at the outer side of the Figure3,the pin or stud K; having moved on bracket, and it is hung for movement freely the arc of a circle about the center it; releases on an arbor or bolt, j, supported in lugs 7" any pressure on the clamp lever J and allows provided on the bracket. The clamp lever is the spring J to turn the clamp lever on the thus pivoted intermediate its ends, the mo\'- pivot and move the head I into the out-ofable member I being at the upper part, whereservice position. In the described position of as below said pivot the clamp lever, J, is parts J, K, the spring M is relaxed to a cerforked or slotted at 7' Figure 5, for the receptain extent, and the thrust rod L and spring tion of a member K which co-operates with M apply no pressure to the clamp lever, but means for applying tension to lever J, whereafterthe tile assembly shall have been deby the movable clamp member I is retained posited in the work holder, the operator in a locked relation to the tile assembly. presses downwardly on the grip is of member Member K is a lever slidably fitted in the K to slide it in the slot 7' and to bring the slotted part of clamp lever J; as shown, lever pin K into alinement with the thrust rod K is provided at one end with a hand grip is, and into frictional contact with lever J whereas the other end of said lever is pivoted whereupon the thrust rod L is moved endby a pin 7: to a thrust rod L, the latter exwise and spring M is placed under tension, tending horizontally through alined opensaid spring and thrust rod acting to retain ings,'m, provided in the bracketG and in the the lever member K in the active posit-ion annular carrier A, Figures 3 and 4. The shown in Figures 3 and 4, and thus the tile. lever J and hand-operated lever K are comassembly is clamped firmly within the work bined for mutual action by a stud or pin K holder. It will be noted that a simple moveextending through lever K and having fricment of lever member K to the raised positional contact with an edge portion of the tion or to the lowered position is all that is slotted lever J, said lever J beingunder the required to release or clamp the tile assembly,

and as this simple movement relaxes or applies the spring pressure, the operator can perform the service easily and with facility.

The stationary bed D is extended outwardly at one side to form a base N, from which rises a column N affording a support for the overhanging frame shown in Figures 1 and 2 as branched at 0, 0, for the accommodation of the grinder shafts P, P, the latter being vertically positioned and journaled in appropriate bearings provided on the branches of said overhanging frame. The column l affords a support for a motor, Q, the shaft 9 of which is furnished with a belt pulley g, the latter engaging with an endless drive belt Q, having frictional engagement with pulleys p, p, provided at the upper ends of the grinder shafts P, P, respectively. Intermediate the grinder shafts is an idler shaft Q} having a belt pulley g adapted for frictional contact with the driving belt Q, and this idler shaft is journaled in appropriate bearings provided as a part of a movable frame Q adapted to be attached fixedly to the frame 0, by the clamping plate or quadrant Q3 and bolt 9, whereby the idler shaft may be shifted with respect to the grinder shafts P, P, for taking up slack in the driving belt Q.

The grinder shafts P, P, are supported over the annular rotary carrier, practically at the rim thereof and in overhanging rela- -tion to the work holders thereon, and these shafts are driven in the same direction, as indicated by the arrows in Figure 1. The grinder shafts P, P, carry grinding members B, C, respective, the same being in the form of disks having abrasive material on the under surfaces thereof, as shown in Figure 2, and more particularly illustrated in the enlarged detail view Figure 6. Each grinding disk B or C is furnished with a hub 9* having a tapering female threaded socket 9 into which is screwed the tapered male threaded lower part p of the appropriate grinder shaft P or P.

Provision is made for the vertical adjustment of the grinder shaft P or P in the bearings provided on the overhanging frame 0, and for the abundant lubrication of said shaft. The lower part of the grinder shaft is encased within a sleeve-like casing member S, which is provided with relatively fine male threads for a part of .its length at .9, whereby said casing member is adapted to be screwed into a part of the frame 0 for accurate vertical adjustment therein. The casing member is recessed and shouldered internally to accommodate a ball race T, which is retained in place by a nut t,'screw-threaded into the lower end of the casing member S. Co-operating with the fixed ball race is a complemental ball race T provided on the lower encased part of the vertical grinder shaft, and this complemental ball race T is retained in position on the shaft by a collar t which encircles the shaft and passes through the nut t, said collar being engaged by a split nut t screwed on a threaded part of the shaft below the nut t attached to the casing member. Confined within the cooperating ball races T, T, are a plurality of series of bearing balls T insuring freedom of motion of the grinder shaft with minimum friction and wear on the high speed parts of the grinding mechanism.

The chamber of the casing member S is charged with lubricant, the leakage of which is minimized by the use of packing rings s s contacting with the shaft, as shown. A dust cap U is applied to the casing member, said dust cap being bolted at u to the frame part 0, and said dust cap having a packing ring u.

In our invention, provision is made for the vertical adjustment of the grinder shaft and its attendant grinding member with respect to the work holder, and such adjustment is performed with accuracy and with facility by the attendant workman. The casing member extends for an appreciable distance above the frame member 0, and at its upper end it is furnished with a grip ring S affording a secure hand hold for the manual rotation of said casing member within the frame member, whereby the threaded casing member may be screwed, more or less, into the frame member for bodily raising or lowering shaft P or P and its accompanying grinding member, together with the ball bearing for said shaft. The lower part of the threaded casingmember is reduced slightly in diameter and provided with a smooth exterior surface, see Figure 6, and this part of the casing member is adapted to slide Within the frame member 0 by the rotative movement of the casing member, and during such adjustment of the casing member to raise or lower the shaft and the grinding member, the nut t and the ball races are movable vertically with the shaft and the casing member, the lock nut t being released and retightened as required. To preclude leakage, a sealing ring V is attached to the lower end of the frame member 0, and a packing 'v has working contact with the smooth reduced surface of the casing member S.

In operation, the rotary carrier is propelled by the motor F at a determined slow speed, whereas the grinding members B, C, are driven at a determined higher speed or speeds by the motor Q. The operators in attendance at the machine assemble tiles into a compact mass and one tile assembly is deposited in each work holder, the operator being required to press down the hand member K for clamping said tile assembly in said work holder. The operations of loading the work holders with assemblies of tiles are performed with ease and facility, and said tile assemblies are presented on the rotation of III the carrier to the successive action of the grinders B, C, one of which is furnished with an abrasive of a character to take off the first, or so-called rough cut, from the-tile assembly, whereas the other grinding member is provided with an abrasive to give a finishcut to the tiles of the assembly. As the carrier is turned by the motor, certain of the work holders move below each grinding member with a slow steady motion, free from vibration or jar, to the end that the tile assembly is reduced in dimensions with great accuracy. The two grinding members operate successively upon the same edges of each tile assembly, and after passing the grinders, each tile assembly is reversed or changed on the holder so as to present another edge to the action of the grinders on the next rotation of the carrier. Such reversal or change of the tile assembly within each work holder requires the operator to release the head I, change the tile assembly within the holder, and to again clamp the tile assembly, all of which operations may be performed with facility, and which reversal may be effected in the period required for the rotation of the carrier in order to present different edges of the tiles in the assembly to the abrasive action of the grinders.

Although we have illustrated and described our invention as adapted for grinding ceramic products such as wall or floor tiles, it will be understood that we may use the machine for grinding other materials than wall and floor tiles, such as for grinding other ceramic products.

Furthermore, our machine may be used for grinding materials or products other than ceramic materials or products, for the reason that the free running table supported on ball or roller bearings and driven by the worm gear provides a machine admirably adapted for heavy grinding duty in surfacing metals in general machine shop .practice.

Instead of finishing tiles singly or individually, we operate upon an assembly or stack of tiles in each work holder, each tile assembly or stack being composed of a number of tiles, say fifteen more or less, of similar form and dimensions, thus reducing the time required and facilitating the operation, with pronounced economy and efliciency. Furthermore, the stack or assembly is under spring pressure as distinguished from a. rigid unyielding clamping action. \Vhen assembled or stacked and deposited in a work holder, it is found that there may be, or is, a variation in the aggregate thickness of one tile assembly as compared with another similar tile assembly, which variation in the aggregate thickness is due. probably. to a slight warpage in certain of the individual tiles composing the assembly. If rigidly locked or unyieldably held in the work holder. as by screw mechanism having a definite thread, there is a tendency to crack or otherwise injure the tiles while so held, but we overcome this objection by a new form of mechanism the clampin action of which is determined and effected by a spring the pres sureofwhichisregulatable with facility. The spring acts through a locking lever, the funetion of which lever is primarily to release the spring pressure or to pick up the spring pressure and transmit the same to the movable clamping jaw. The action of the lever is subsidiary to the tension of the spring, the secondary purpose of the lever being to afiord convenient means for the manual control of the work holder. The lever functions mainly as a means for bringing the spring pressure into service for clamping the tile assembly and as a means for shifting the spring pressure to an out-of-service relation to the tile assembly. The spring is comparatively long, with a relatively slight compression, the effect of which is that irrespective of the variation in the aggregate thickness of the tile assembly the actual spring pressure applied through the movable jaw remains approximately constant, whereby provision is made for efliciently retaining different tile assemblies which vary in aggregate thiclmess, and the spring pressure is determined and regulated for holding such variable thicknesses in tile assemblies without cracking or injuring the individual tiles of such assemblies.

The grinding mechanism the carrier of which is designated 0 constitutes a unit movable rotarily around the column N for shifting the grinding disk or disks B, G, into a service relation to the material in the work holders on the revolvable carrier or said unitary grinding mechanism may be shifted rotarily upon the column to out-of-service relation away from the work on the rotary carrier, with a view to moving the grinding disk or disks B, C. to a position at one side of the carrier in order that access may be obtained with facility to the disks B or C for the purpose of cleaning orrenewing said disks, B, C. The frame 0 is sleeved on the column N and clamped thereon by the element X which, when released (see Figure 2) provides for rotary motion of the frame on said column whereby the grinding mechanism as a whole may be turned to a position overhanging the work on the rotary carrier A or said grinding mechanism may be turned around the column in a direction away from the work. As shown in Figure 1, the frame 0 is provided with split. rings Y. Y which may be tightened or loosened as re uired by element X, but when the frame and the grinding mechanism are in service relation to the work on the rotary carrier. these split rings are clamped firmly upon the column for retaining the grinding disks in the required positions to operate upon the work. The grinding disks (two or more) are driven by a motor Q common to all the disks, such disks being driven through a single belt Q in frictional contact with pulleys on the motor shaft and the disk spindles. Said transmission belt is held in operative engagement with the pulleys by the action of the idler pulley Qi. carried by the pivoted arm Q and locked in place by the quadrant 9 the latter providing for the adjustment of the idler pulley in taking up slack in the transmission belt and for keeping the mechanism in operating condition.

Each grinding disk is demountably and fixedly attached to its spindle by simple and effective means shown in Figure 6. The hub r of the disk is provided with a tapering socket the wall of which is provided with a thread. The lower part of the spindle is made tapering and provided with a male thread. To couple the disk to the shaft, the hub is screwed onto the tapered spindle, and

by reason of the conical threads the disk and spindle are locked by a wedging action. to fixedly attach one part to the other so as to overcome disengagement of the disk from the spindle under service conditions, although the disk may be unscrewed by hand from the spindle.

The spindle, the disk. and the supporting means therefor constitute a grinding head adapted to be raised or lowered as a unit for the purpose of positioning the grinding disk in the required operative relation to the material to be operated upon and to compensate for wear in the service of the grinding member.

The means for raising or lowering the grinding unit is a 'fine screwthread on the exterior surface of the casing S, whereby a nicety of adjustment is obtainable in the relation of the under face of the grinding disk to the upper surface of the tile assembly. Said casing is equipped with ball bearings for the spindle, to the lower protruding end of which the grinding disk is affixed, said ball bearings being adequately lubricated and being housed within the casing by dustexcluding means so that no fine particles of material can enter the casing or the bearings. The casing is rotatable at will by simply applying pressure to the hand ring S. and such rotary motion screws the casing downwardly or upwardly within the frame part 0 according to the direction of the rotary motion, but it is to be noted that the rotation of such casing operates to raise or lower the casing itself and to carry with the casing the spindle, the grinding disk. and the bearings for the spindle as well as the dust-excluding means, whereby the grinding head as a unit may be adjusted vertically, with the result that all parts of said grinding head remain m the required operative relation one to the other in all positions of the grinding head.

Although we have shown and described the machine as equipped with a plurality of grinding heads, it is not intended to confine the machine to the use of the particular member shown, for the reason that the part is operative with a single grinding unit, or the number of grinding units may be increased if desired. Obviously, the belt Q may be replaced by a belt to drive only one of the grinding disks.

Having thus fully described the invention, what we claim as new and desire to secure by Letters Patent is:

1. In a tile grinding machine, a carrier, and a series of work holders thereon, each work holder including a plurality of clamps one of which is movable, a clamp lever for imparting movement to one of said clamps, a thrust rod an actuating member for said thrust rod, and a manually operable member pivoted to said thrust. rod and frictionally e11- gagcd with said clamp lever, said manually operable member being movable atwill into and out of alined relation to the thrust rod.

In a tile grinding machine, a carrier, and a series of work holders thereon, each work holder including a plurality of jaws, one of which is movable, a lever to which the movable jaw is attached, a spring the energy of which is applied through said lever to the movable jaw, a thrust rod, and a manually operable member pivoted to the thrust rod and engageable with the clamp lever.

3. In a grinding machine the combination with a rotary carrier, and a pivotal column, of a frame rotatably mounted on the column, a plurality of grinding members carried by the frame and normally occupying a service relation to said carrier, and a motor carried by the frame and having a common driving connection to said grinding members, said rotatable frame being movable with the grinding members to positions into and out of servlce relation to the carrier for all of said grinding members simultaneously.

4. In a tile grinding machine, a carrier, a work holder thereon, said holder including a pivoted lever, a clamp member connected to said lever by means of a universal joint, a thrust rod provided with spring means. and means co-operating with said thrust rod and said lever for causing said clamp member to resiliently clamp a plurality of tile members.

In a tile grinding machine, a carrier, a work holder thereon. said holder including a lever pivoted intermediate its ends, a clamp member connected to one end of said lever by means of a universal joint, a thrust rod provided with spring means, and means cooperating with the said thrust rod and the other end of said lever for causing said clamp member to resiliently clamp a plurality of tile members.

6. In a tile grinding machine, a carrier, a work holder thereon. said holder including a pivoted lever resiliently connected to the carrier, a clamp member connected to said lever by means of a universal joint, and a resiliently mounted thrust rod provided with means adapted to abut one eml of said lever to cause said clamp member to resil'ently clamp a tile assembly.

7. In a tile grinding uniehine, a carrier, at work holder thereon, said holder including a slotted. pivoted -.lan'1ping lever. a thrust rod provided with a member adapted to be received by the slot in the sad lever, said member being provided with means adapted to abut the said slotted lever, and means for resiliently holding said member in abutting contact with said clamping member so as to clamp a plurality of tile members between said carrier and said clamping lever.

8. In a tile grinding machine, a carrier, a work holder thereon, said holder including a slotted, pivoted clamping lever resil'ently connected to said carrier, said lever having a clamp member, a thrust rod provided with a member adapted to be received by the slot in the said lever, said member being provided with means adapted to abut the sad slotted lever, and means for resiliently hold-' ing said member in abutting contact with said clamping lever so as to clamp a plurality of tile members between said carrier and said clamp member.

9. In a tile grinding machine, a carrier. a work holder thereon, said holder including a slotted. pivoted clamping lever having one end resiliently connected to the carrier, a thrust rod resiliently mounted on .said carrier and provided with a pivoted member adapted to be received in the slot in the lever, an abutment 011 said thrust rod member adapted to contact said slotted lever and exert a force on said clamping lever so as to clamp a plurality of tile members between said carrier and said clamping lever.

10. In a tile grinding machine, a carrier, a work holder thereon including a plurality of clamps, one of which is movable, a clamp lever for imparting movement to the movable clamp, a thrust rod, resilient means for holding said thrust rod under tension, and a manually operated member associated with said clamp lever and said thrust rod. said manually operable member being movable at will into and out of alined relation to the thrust rod to move said clamp lever into and out of clamping position.

11. In a tile grinding machine, a carrier, a work holder thereon including a plurality of jaws, a resiliently mounted lever attached to one of said jaws and adapted to move the jaw. a resiliently mounted thrust rod, and a manually operable member pivoted to the thrust rod and engageable with the lever.

12. In a tile grinding machine, a carrier, a work holder thereon, said holder including a pivoted lever. a clamp member, means for pivoting said clamp member to said lever, a

thrust rod provided with spring means, and

means co-operating with said thrust rod and said lever for causing said clamp member {)0 resiliently clamp a plurality of tile memers.

13. In a tile grinding machine. the com-.

binalion ot, a carrier. a work holder thereon, said holder including a pivoted lever resiliently connected to said carrier, a clamp men1- ber, means for pivoting said clamp member to said lever. and a resiliently mounted thrust rod provided with means adapted to abut one end of said lever to cause said clamp member to resiliently clamp a tile assembly.

14. In a tile grinding machine, a carrier, a work holder thereon. said holder including a pivoted lever resiliently connected to said carrier. said pivoted lever being provided with a clamp member, and a resiliently mounted thrust rod provided with means adapted to abut one end of said lever to cause said clamp member to resiliently clamp a tile assembly.

15. In a device of the character described, a work holder, includinga plurality of jaws. a lever connected to one of said jaws and adapted to move said jaw, a resiliently mounted thrust rod, and a manually operable member pivoted to said thrust rod and engageable with said first-mentioned lever.

16. In a tile grinding machine, a carrier, a work holder thereon, said holder including a pivoted lever provided with a. clamp member. a resiliently mounted thrust rod provided with means adapted to abut one end of said lever to cause said clamp member to clamp a tile assembly and means for normally holding said lever in out-of-service position when said thrust rod is in inoperative position.

17. In a tile grinding machine, a carrier, a work holder thereon.'said holder including a pivoted lever provided with a clamp member, a resiliently mounted thrust rod provided with means adapted to abut one end of said lever to cause said clamp member to clamp a tile assembly, and means forum-nually holding said lever in out-of-service position when said thrust rod is in inoperative position. said last-mentioned means including a spring connected to said holder.

In testimony whereof we have hereto signed our names this 17th day of September, 1997.

THEODORE C. PROUTY. VVIIJLIS O. PROUTY'.

CERTIFICATE OF CORRECTION.

Patent No. 1,862,704. June 14, 1932.

THEODORE C. PROUTY ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 7, ,lines 112 and 113, claim 17, for "manually" read normally; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 4th day of October, A. D. 1932.

M. J. Moore, (Seal) Acting Commissioner of Patents.

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