US1914205A

US1914205A - Machine and method of shaping silica and the like

Info

Publication number: US1914205A
Application number: US546536A
Authority: US
Inventors: Irvin F Hooper; Berthold F Niedergesass; Philip K Devers
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1931-06-24
Filing date: 1931-06-24
Publication date: 1933-06-13
Anticipated expiration: 1950-06-13

Description

June m, 1933,

z. F. HOOPER ET AL MACHINE AND METHOD OF SHAPING SILICA AND THE LIKE '7 Sheets-Sheet 1 Filed June 24, 1931 Inventors, Irvin F H00 per Berbhold F Nledergesass hlllp K Devers. by Then" Attorney June 13, 1933. g! F HQQPER r AL 1,914,2(15' MACHINE AND METHOD-0F SHAPING SILICA AND THE LIKE Filed June 24, 1931 7 Sheets-Sheet 2 Inventors: Irvin FHoopef, Berthold FT Niecterrgesass' Philip K. Devers. y Their Attorney.

June 13, 1933. a. F. HOOPER ET AL MACHINE AND METHOD OF SHAPING SILICA AND THE LIKE Filed June 24, 1931 7 Sheets-Sheet 3 ////I/I/I/////// u I "Wham Inventors: Irvin F Hooper, Benthold F Nledengesass.

l l'nhp K. Dsvens. by Then" Attorney June 113, 1933. n. F. HOOPER ET AL MACHINE AND METHOD OF SHAPING SILiCA AND ,THE LIKE Filed June 24, 1931 7 Sheets-Sheet 4 6 l na Inventors. Irvin E Hocvper, Bert 910M F Niedr cesass, Phiip K. Haw-swa :3 y I T5165 Att-cmngy.

June 13, 1933. I. F. HOOPER ET AL 1,914,205

MACHINE AND METHOD OF SHAPING SILICA AND THE LIKE Filed June 24. 193i '7 Sheets-Sheet 5 y r%& e s er n r Cl 6 P t r t H E D t n ,A m m r Imm m a v H .h r

o 1% Y r b e. B

June 13, 1933. 1. F. H OOPER ET AL 1,914,205

MACHINE AND METHOD OF SHAPING SILICA AND THE LIKE Filed June 24, 1931 7 Sheets-Sheet 6 f F ig.l

Inventors: Irvin T. Hooper;

Berthold F. Nieder-e sass.

Philip K. Devers,

Their Attorney.

June 13, 1933. PER T AL 1,914,205

MACHINE AND METHOD OF SHAPING SILICA AND ,THE LIKE Inventors:

Irvin FHoopsr, I I Berthold T. Niederesass,

Phili K. Dever s,

Patented June 13,-

UNITED STAT S- PATENT OFFICE TO' GENERAL ELECTRIC OOH- -IMiACH-IN1'2- METHOD OF SHAPING $ILIOA. AND THE LIKE n Application filed June 24,

The present invention includes both a I method and anapparatus for fabricating shaped articles from elongated stock, such, for example, as'tubing. Our invention is particularly applicable to the manufacture of articles, from a refractory vitreous material, such as fused silica, which, because of its physical properties, cannot be readily shaped" by methods commonly in use for making shaped articles from other materials, as for example, pressing, casting, ma-

chinirig or sintering. Our invention can be advantageously 'appliedto the manufacture of spark plug insulators.

While the-novel process which constitutes one aspect of our invention may beemployed for the hand fabricatlon of shaped articles, it may be even more advantageously carried out by an automatic machlne as herein described and claimed. The advantages of such a machine in the quantity production of standardized articlesaccompanied by uniformity and low cost are obvious.

Among the novel features of our invention are the following: A method of fabr eating articles involving the combination of endwise and transversely applied moldin pressures upon a portion of elongated stoc material having a longitudinal channel therethrough' and which stock has been rendered plastic by heating. Also afabricating' operation' involving the combination of fusing and twisting operations on elongated stock having a longitudinal channel therethrough whereby an internal bore of substantially uniformcross-section is sized in the fused portion of the stock and in approximately symmetrical relation with respect to the enlargement.

Our invention involves also the combination of externalshaping operations upon material rendered plastic by heat combined '1931. Serial No. 546,588.

portion of the stock to produce a firing tip. Our invention utilizes in the fabrication of silica articles a heating operation whereby only an outer layer or skin of material is rendered plastic, the article as a whole remaining non-plastic, and in this condition bein indented or grooved for producing a condltion of discontinuity which will render easy severance of a completed article from unformed stock material at such grooved region. Our invention involves the combination of shaping and cutting operations whereby an insulator body may be formed from the elongated stock provided with an enlargement comprising. suitable bearin surfaces for the insulator and with atapered portion comprising a firing tip which is shaped to the desired configuration, and the tip thus formed trimmed at its end to produce the desired tip length.

i The machine constituting a feature of our invention provides a plurality of mechanism groups herein termed stations for carrying out the various stages of fabrication of shaped articles of exact predetermined contour from tubing, or other elongated stock material of simple-form, including means for carrying out the above process steps together with such auxiliary steps as may be required for producing completed articles.

The'stock is advanced from station to station, the mechanism of each station performing one or more operations'on the stock, such operations briefly comprising an" upsetting operation whereby a spherical enlargement in a part of the stock is produced. The ma-( chine provides mechanism for carrying out external shaping operations which may be combined with internal shaping operations whereby, a desired contour is glven the article; also means for carrying .out an indenting operation preparatory to a severing operation whereby finally the completed article is broken away from the unfinished stock and is delivered by the machine.

These and other features of our invention will be described in greater particularity in the following specification taken in connection with the accompanying drawings.

IRVIN F; HOOPER, OF-SAUGUS, AND BERTHOLD F. NIEDERGFSASS AND PHILIP I.

' DEVERS, 0F LYNN, MASSACHUSETTS, ASSIGNOBS '25., A CORPORATION OF I IEWYORK tion; Fig. 4 represents a section of the ing station on line H of Fig.1; 1g. 5

represents a section through the holding chuck on the line b-b of Fig. 3; Fig. 6 represents a side elevation and partial section of the first operating station or upsetting station and illustrating the rocker arm for up and down motion; also the relative motiont of the stock and upsetting abut-' ment; Fig. 7 represents a plan of operating arm (Fig, 6) and partial section of relate parts; Fig. 8 represents the sizing pin; Fig.

9 represents a modification in elevation and partial section of the construction shown in gig. 6, dispensing with the use of apin;

1 tia? shaping station; Fig. 11 represents a side elevation of Fig. 10 showing flames and abutment for bringing the forming rolls into operative position; Fig. 12 is a sectlon 7 taken on line d-d of Fig. 11 and showing bearing and pin and operating sleeve in section; of Fig. 11; Fig. 14 represents a front elevation of the final taper molding station; Fig. 15 represents a side elevation of Fig. ld'showing flames; Fig. 16 represents a side elevation in partial section of the indenting station preliminary to severing; Fig. 17 rep resents a lan of cam operating parts of Fig: 16; Fig. 18 represents a side elevation of the severing or breahng-ofi' station showing hammer; ig. 19 represents a front elevation of Fig. 18; Fig. 20 represents a plan view of the anvil-wheel at breaking-ofi' station; Fig. 21 represents a detail of the gauging spindle shown in Fig. 3; Fig. 22 represents adetail of the upsetting or enlarging operation; Fig. 23 represents a detail of the prelirnlnary or rough rolling or molding operation; Fig. 24represents a detail of the final molding operation; Fig. 25 represents a detail of the rough tapering operation; Fig. 26 represents a detail of the final taporing operation; Fig. 27 represents an enshap larged section of Fig. 26, illustrating ing 'tip end and cutting ofi of tip ig. 28

represents adetail of the indenting station;

Fig. 29 represents a-detail of'the'severing or breaklng-ofi station; Fig. 30 re resents a modification of the arrangement s own in -Fig. 10 for hringing' shaping or molding means into operative position, and Fig. 31 represents a perspective view oi'f thee'ssential operating mechanisms of the machine and more clearly illustrating their cooperative relationships.

aug- 10 represents a front elevation and par- I section of the rolling, or enlargement ig. 13 is a section taken on line We have hereinafter described an auto-- aaiaaoa ment of our invention and comprises details 7 of importance in that particular embodiment, the invention may be carried out by other forms of mechanism suitably applied as covered in the appended claims.

The general operation and application of the salient parts will first'be described by us, after which the construction and operation of the various mechanisms and certain modifications thereof will be described in detail, and the manner in which they are brought into cooperative action.

While in the description which follows reference is made specifically to tubes or tubing, it is to be understood that our invention is not limited to the employment of tubular stock. In the specific production of spark-plug insulators, We prefer to use tub- 'ing. The machine is adapted to receive and operate upon suitable lengths of the silica tubing which is to be worked upon for shaping into the required configuration and subsequently detached and delivered automatically to a suitable receptacle provide to receive the finished insulators. 5

Referring to Figs. 1 and 31 of the drawings, A, B, C, D, E, F, G and H represent a plurality of stations whereat the various steps of operation of the invention are performed. Referring more specifically to Figs. 1, 2, 3, 4 and'5, each length of tubing 9 to be operated upon is fed lengthwise through the spider guides 10 provided with chucks 11 adapted to hold it and grip it tightly or to open and permit feeding, as desired. The spider uides 10 are carried on a spider 12 mounte on a pedestal 13 (Fig. 2) onthe table of the machine frame 14:. The tube 9 is heated at a suitable region of its length while suspended in the chucks 11, and while thus held, 'endwise pressure so as to enlarge the diameter of the heated region is applied to the heated stock at its free end (Fig. 6) by means of an upwardly moving part 15.

A. number of tubes may be heated, worked,

figures, extending through a sleeve 16 in the pedestal 13 is a shaft 17' mounted in suitable bearings and connected at its top end to a large gear 18 rotated by said shaft, this gear 18 meshing with smaller gears 19, (Fig.

31) one on each spindle for turni the respective chucks 11 to rotate the tubing held thereby. The driving mechanism for the a gear 29 mounted on the countershaft 28,

another countershaft is driven, upon which are mounted

gears

31 and 32 and a bevel gear 33 which meshes with a gear 34 fixed onthe lower end of shaft 17; The shaft 17 is thus driven in the direction of the arrow and rotates the gear 18 at the top of the shaft in the same direction and revolves the chucks 11 and the stock held therein. The cam actuating means provided for operating the various levers and fingers at thev respective stations will now be described, toether with the means for rotating the boreorming pin.

Shaft 35 (Fig. 31) is driven by means of gear 36 through idler gear 37 having meshing engagement with said gear 36 and with gear 32 on countershaft 30, the shaft 35 being rotated inlthe direction of the arrow shown on gear 36. By means of cams 38' and 38 fixedly mounted on shaft 35 in conjunction with rollers 39 and 40 and fingers 41 and 42, the operating motions at the gauging station (station A) are controlled. The operating motions of station B '(upsetting or enlarging station) are accomplished by means of cam 43 fixedly secured also to shaft 35 engaging with roller 44 on lever 45 this lever in turn being connected to a shaft 46 by means of link 47 and crank lever 48 fixed on shaft 46. A finger 49 on shaft 46 effects the upsetting motion at station B. Rotation of the bore-forming pin is secured at this station by means of the chain 50 (driven in the direction of the arrow) on the sprockets 51 and 52, the latter being fixed on a vertical shaft 53. At the lower end of this-shaft is a bevel gear 54 meshing with a similar gear 55 fixedly carried on the end of countershaft 28.

The mechanism for performing the required operating motions at stations C, D,

E and F will now be described. On shaft 35 is fixedly secured cam 56 which actuates the,

forked members or fingers 57. The shaft 46 actuates finger 58 for operation at stater being connected by a link 63 and crank 64 to shaft'60. Y

The operating motions at stations E and F (the tapering stations) are controlled by means of cams 65 and 66 (on shaft 35) which actuate fingers 67 and 68 by means of rollers 69 and 70 res 'ectively on said fingers. Stations G and (the indenting and cutting-01f stations respectively) are operated by

fingers

71 and 72 mounted on shaft 73 which is connnected by crank 74 and link 75 with crank 64.

The means for supplying the gas (oxygen and hydrogen) to the various burners will now be described. The

tanks

76 and 77 contain. oxygen and hydrogen, the two gases being in the separate tanks, the

pipes

78 and 79 conveying the gas through saidpipes to the

gas valves

80 and 81. By means of suitable connections, such as by rubber gases'to the

gas valves

86 and 87 and from the outlet pipes 88 and 89 to a gas manifold (not shown) from which it is distributed to the burners at stations C, D, E, F and G. Of course, the specific arrangements for supplying'the fuel for heating may be modified in any suitable manner.

On one end of shaft 35 is a cam 90 engaging with a roller 91 operatively arranged on a lever 92 and connected by a link 93 with an arm 94 on the

gas valve

80 and 81. The cam 90 is so timed that the fires at station B will play uponthe work at this station by means of suitable burners at the predetermined required sequence of operations at this station. The arm 94 operates to actuate short levers 95 and 96 on the

gas valves

80 and 81, thus regulating the flames at station B from pilot condition to full flame condition.

The

gas valves

86 and 87 are similarly operated by means of. short levers 97 and 98, :trm99, link 100 and crank 101, the latter being suitably mounted on shaft 60. By

virtue of this arrangement, the flames or may beimparted to the various chucks and stock supported therein. This indexing mechanism and manner of operation is best illustrated in detail in Fig. 31 wherein cam .step-by-step or station-to-station movement 103 on shaft 35 actuates lever 104, thus in 3 turn operating bell-crank 105, rod 106, crank 107 and reciprocating rod 108 (all suitably supported) to release indexing plate 109, permitting the latter to drop and allow clutch 110 to closed and engageably coop- "crate with the fixed gear'111 on shaft 17.

Indexing plate 112 is secured rigidly to sleeve 16 and is integrally connected with plate 113. A cam 114 rotates'with indexing plate 109, the former carrying indexing pin 115. In the plate 112 are slots 116 with which pin 115 engages to turn sleeve 16 and integrally connected parts. The earn 114' is so shaped as to cause revolution of sleeve 16 and above-mentioned parts, thus rotating chine from motor speed.

Referring to Fig. 3, the gauging or adjustable stop 118 is normally in the position shown being supported on a. spindle 119. The spindle 119 is enclosed by a sleeve 120 having a bearing 121 and the gauging stop 118rests on a flange or table 122 provided with a sleeve 123 and secured to the spindle 119 at the threaded top of the latterand adjusted to a predetermined height by means of a set screw 124. Cooperating with the chuck 11 at this station is a chuck arm 125 mounted on pivots 126, the chuck arm engaging a cam roller 127 mounted ona. cam-operated shaft 128 supported in a bearing 129. The cam-operated shaft 128 is operated by means of a cam 38 on" shaft 35 (Fig. 31). -The chuck 11 is normally open when stock 9 is inserted therein. The dropping ot the cam-operated shaft 128 by means of cam 38 locks the chuck on the stock. Cam shaft 119 now drops, by means. of cam. 38, a suficient distance to clear the end of the stock 9 and permit the latter to he responsive tosubsequent operations.

The mechanism by which the upsetting or enlarging operations are performed are illustrated in 6 wherein the sleeve 130 is slotted to receive the end of the forked finger 49 whereby the latter may be connected to the rolls 131, the arm 49 beingactuated to slide in the slot 132 to reciprocate the upsetting head 15. A pin 133 (preferably square as shown in Fig. 8) is secured in the head 15, so that when the linger 49 is actuated to cause upward movement of the upsetting member and pin, a bore of the. size as determined by the size of the pin will be formed in the channel of the stock. On the downward motion of said arm, the pin'is withdrawn. j I The upsetting head 15 is given a relative motion with respect to the chuck 11 and stock 9 by means of the chain 50, as previously described, and may be driven in the speed of the maopposite direction to the chuck 11 and stock 9. The upsetting head 15 is provided with a heat-resisting sleeve 1340f material such as or slip of the latter with reference to the speed of rotation of chuck 11 and stock 9. A. similar pin is provided at each succeeding station at which the article or insulator may be rotated and a predetermined diameter of bore is to be sized in the channel.

Referring to Figs. 10 and 11 (the enlargement or ball-rollin station), cam 56 on shaft 35 causes the torked finger 57 to rise and actuate rod 135 to also rise and carry with it the cam head 136 comprising the spring 137 upon which is seated a supporting plate 138 for the shaping rolls 139. These rolls 139 may be either of metal or of a highl refractory material, such as zirconia. he plate 138 is provided with lugs 140 having projections u on which the rolls are'mounted, and binge levers 141 to which are attached springs 142 seated in lugs 143. Cam rollers 144 travel on the cam-head 136 downwardly when said head rises, thus closing-in theshaping rolls 139, and when the rod 135 drops, the rollers 144 travel upwardly on the cam-head by the expansion of the spring 137. The function of the springs 142 is to provide a downward bias of the shaping rolls 139 onthe stock 9. Suitable flames 145 emerging from burners 146 are provided at the required working stations to heat the stock to the required temperature. In Figs. 10 and 11 reference may be mad to the means which adjust the limiting height to which the ball-shaping and tapering rolls respectively may rise. A stop 147 on a rod 148 is adjustable as to its height with relation to the base fixture 149 of the machine. The stop 147 is adjusted so that its bottom surface will engage with the plate 138 at 150 (Figs. 11 and 15) and when this engagement occurs, the spring 137 will compress and close-in the ball rolls or tapering rolls, as the case may be, to shape'the stock under pressure by the mechanism dc scribed heretofore.

In Figs. 14 and 15, the same general mechanism and movements are involved for this station- (the tapering station) as for the enlargement or ball-rolling station. The rolls 151, however, have a trustro-conical shape, as shown, but as illustrated in Fig. 15, the main body' of the rolls may be heated by flames 145, while the top portion 152 thereof is relatively cold or unheated. The purpose of this procedure is to provide relatively cold or rigid seating surfaces for the enlargement, while the lower or heated portions of the rolls are giving a tapered shape to the article or insulator under formation, and insuring a symmetricalshape for the tapered tip of the insulator. The steps of forming the desired contour of the enlargement (the latter being identified by the numeral may be accomplished at either the same station, or additional shaping stashown in Fig. 31) and 158 represents a mechanism by the fixture.

short spindle or stud shaft supported bx bearings 159 carried by the fixture 156.

set-screw 160 on finger 71 is provided for adjusting the angular relation or travel of the wheel 163 with respect to the stock when the wheel leaves the latter. A second adjusting screw 160 on stud shaft 158 ad justs the tension of the spring (shown in dotted lines) on said shaft for the'purpose of maintaining the wheel 163 in the desired pressure relation with the stock. Supported by the spindle 154 is a head 161 (adjustable as to height by means of the screw-thread spindle 154) in which is mounted a stud 162 upon which is rotatably carried a grooving wheel 163 free to rotate and which'engages with the stock 9 above the enlargement 153. When finger 71 is caused to throw in the spindle 154 and sleeve 155, the

grooving wheel 163 indents the heated skin of the stock 9 and the wheel 163 rotates by virtue of its frictional engagement with the rotating stock 9. After the groove is made, the cam-actuated shaft 73 and finger 71 operate to permit the'grooving wheel 163 to drop out-of engagement with the stock.

Figs. 18, 19 and illustrate the detailed of the breaking-off station wherein 164 represents the base of the fixture 165 bolted to the frame 14. A shaft or spindle 166 in a sleeve 167 is attached to a lever 72 fastened to the shaft- 73 (Fig. 31) and is caused to rise thereby until the hammer 168 is in operative relation with the stock 9 (see also Fig. 29). The fixture also supports a wheel 169, the support for the same being mounted in a bearing 170 carried \Vhon the chuck 11 is indexed to arrive at this station, the wheel 169 rotates in the groove which has been formed at the indenting station and the hammer 168 .taps the stock 9 in the relation best shown-inFig. 29, breakingit off with quite a clean or regular fracture, and the finished article or insulator rolls down a chute 185 (Fig. 18) into a suitable receptacle (not shown).

In Fig. 9,- a modification is shown of the means for sizing the required bore diameter through the insulator when the stock is in the form of a tube, having a channel 171 and an .airor gas connection 172 communicating with the channel 171. Air or other gas under pressure is pumped through the passage of the connection 172,v and while the tube is locally heated to plasticityfthe air pressure is so regulated or proportioned as to prevent collapse of the plastic inner walls of the tube, or if they are allowed to collapse, to control the same to maintain a bore of the desired uniform. cross-section in the tube channel.

Referring to Fig. 30, a modification shown of the means for controlling the engagement of the shaping rolls with the stock. In this case, levers 173 which support the rolls are designed to come in towards the stock in a lateral or horizontal line instead of on-an angle, as in the other figures involving this general type of mechanism.

It has been found desirable to water cool certain parts of the machine, (especially in proximity to the quartz stock hol ing means) due to the higher temperature of operation in working quartz, as. distinguished from the working of glass. Water cooling of such a machine for fabricating articles of glass would, in fact, be doubtless impracticable because of the danger of cracking the glass articles subjected to the various operations of the machine.

To this end a suitable water receptacle or trou h 174 (Fig. 4) above spider 12 is pro-,"

vide the wall of which surrounds the spider 12 and gear 18. A'sump 175 also surrounds pedestal 13. An inlet drip pipe 17 6 is suitable arranged above the trough 174 for conveying water to said trough, and an overflow outlet 177 from tropgh .174 is provided in boss 178, a drain pipe 179 being fitted into said outlet at the bottom thereof and the other end of this drain pipe terminates in sump 175, supplying water to thelatter, pipe 179 revolving with spider 12. A drampipe 180 carries the water in to be cooled and used over again, as desired.

12o sump 175 away either as refuse water or In proximity to chucks 11 is an annular 181 and 182, having each an inlet and outlet connection (not shown). This waterjacket structure may extend circumferentially around the machine under all the chucks 11 at the various stations, or only at such stations where water-cooling is v-water-jacketed structure comprised of ducts needed. The structure is supported by means of

suitable standards

183, 18 1 fastened to any accessible location on the ma-- chine frame 14.

l The operation of our invention is as folows:

3) of the machine is set at the required height to space the predetermined length of stock 9, the stock resting on the stop as it is fed through the openjaws of the chuck 11. The jaws are then closed by the operation of the machine wherein cam-operated'shaft 128 and roller 127 engaging with chuck-arm 125 lock the chuck 11 on the stock 9, and the stop 118 drops about by the operation of the machine at the right time period in the cycle of operations. This "leaves the stock suspended with a free end above the stop 118. The next step is to produce an endwise pressure upon this free end, and as themachlne is properly indexed by the indexing mechanism hereinbefore described,.the'chuck 11 with its stock 9, is carried around ci'rcumferentially to the upsetting or enlarging station (Fig. 6) where the flames 145 heat it locally to fusion temperature. At this statlon, the member 15 is raised, causing it to impinge against the free end of the stock andu set it, producing the enlargement 153 t ereof. Simultaneously, the pin 133 carried in member 15 enters the channel in the tubular stock and sizes said channel to the-required diameter and produces the required bore, the member 15 and pin 133 being given a relative motion with respect to t e direction of rotation of the stock 9, either by means of gearing or by the chain or by the sllppage or lag of the part 15 with reference to the rotation of the stock. The machine is again indexed, and the chuck 11 and stock 9 with its enlargement as now formed is carried to what we designate as the ball-' rolling, station. (Figs. 10, 11, 23 and-2t),

tional station or. stations provided for final rolling to' the ultimate shape and dimensions, or these rolling operations may all be performed in one operation at this station, as found the most desirable. Before each rollingoperation, the rolls and the pin are smeared with a lubricant, such as graphite,

The abutment or gauging stop 118 (Fig,

antenna which may mixed with a vapori zablmmaterial. When applied to the pinthe lubricant becomes vaporized and serves to. produce pressure in the bore and prevent collapse of the walls around the pin. After the ball-rolling operations are performed, the pin 133 is again withdrawn, and the work thus far accomplished is indexed to carry it to the tapering station, it being understood that the flames 1 15 are brought into and out of operation locally upon the stock as desired.

We have illustrated in Figs. 14, 15, 25 and 26 two tapering stations, but it is to be understood that the tapering may also be performed in one operation, if desired. Fig.

25 represents the character of rolls utilized for the rough tapering station, and Figs. 14, 15. and 26 that employed in the final taper-, ing station. In the case of the final tapering station, the rolls are heated at the portions 151 thereof by the impingement thereon of the flames, 145, Fig. 15, and the portions 152 thereof are unheated, thus providing rigid or relatively cold bearing surfaces for the convex portions of the enlargement 153, and thus giving a definite taper to the tip of the insulator, as determined by the adjacent configurations of the roll portions 151. These rolls are made of suitable material, such as graphite, or metal, but preferably the latter. The tapering rolls at the final tapering station are provided at thebase of each roll with a cutting wheel 151,.and having a contour as shown in the enlarged sectional view, Fig. 27. It will be seen that by virtue ofthe diameter and shape of these wheels that when they are brought into contact with the insulator tip they cut ofl the end of said insulator to trim the tip as in Fig. 27, the cutting wheels being rotatable .by frictional engagement with the rolls as in the case of the indenting station. In case the length of the tapered portion is the final length desired, the cutting-ofl operation of the ta ered portion may be dispensed with, and t e shaping of the tip only may be performed at this stage of the operations. At the taperingstations, a pin smaller in diameter than the pin 48 employed at the previous stations is used so that the bore in the tip will be smaller than the bore through the enlargement arid shaft, although in line with and communicating with the larger bore. This is to reduce the possibility of plugging up of the tip bore with residue from the products of combustion of the engine where the insulator is used for spark plugs to be utilized in internal combustion engines.

After'the taper has been given to the insulator and the tip thereof shaped and cut elf as described, the cam 66 on the shaft 35 causes the tapering rolls to drop out of operative engagement with stock 9. The

machine is again indexed to rotate the article thus far formed and suspended in the head 11 until said article arrives at the indenting or grooving station, Figs; 16 and 28. Here the grooving wheel 163 is brought into proper relation with the stock 9, which is locally heated in such a manner that slightly more than the skin or outer surface of the stock is penetrated by the wheel, and

a weak plane formed-inthe stock at a region sufliciently remote from the enlargementf153 to-constitute a shaft for the article or msulator. This heating of the skin only of the insulator prevents distortion of the bore or enlargement, as the plastic temperature is not reached in the interior of the insulator. It would be diflieult if not impossibleto carry out such an operation with glass or other'vitreous material.

The grooving wheel 163'is' now dropped away from the stock by the proper actuationof finger 71 on shaft 73, the machine is again indexed automatically .as before, and the next or breaking-off station is reached, Figs. 18, 19,

20 and 29. At this" station, the anvil or wheel 169 has a similar shaped edge to that of the grooving wheel 163 at the indenting station, so thatwhen the anvil is brought up to the stock, the edge will enter the groove in the skin of the latter, which groove was formed at the indenting station, The hammer 168 is brought into play by the operation of finger 72 and caused to lightly tap the tapered portion of. the article or insulator resulting in 'a regular fracture at the groove,.as best illustrated in the diagrammatic view (Fig.v 29), and discharging the insulator through the chute 185 into a suitable receptacle to receive the same.

All of the above operations are performed automatically in sequence, the chucks 11 being loaded with the raw stock at the loading or spacing station, and the finished product being broken off and discharged at the breaking-oil station.

What we claim as new;and desire to secureby Letters Patent of-the'United States, 1s j 1. The method of forming shaped articles from elongated stock of vitreous material which consists in heating a zone of said stock to atemperature ofplasticity, exerting endwise pressure on said stock to ,,,pro-' duce an enlargement at said heated zone,

molding said enlargement externally to produce a desiredconfiguration thereon, forming a channel of predetermined cross-section ,through saidenlargement and through portions ofsaid stock adjoining said enlargement and severing said enlargement together with adjoining extensions from the main body of said stock.

2. The method of forming shaped. articles from elongated stock of vitreous material having a channel therethrough which consists in rotating said material, applying upon a zone of said material a flame which is capable of' heating said material to a temperature of plasticity, exerting sufiicient endwise pressure upon said stock to produce an enlargement of diameter at said heated zone, molding said enlargement externally -to substantially spherical configuration,

molding a portion of said stock adjacent .said enlargement, sizing a bore in said stock uniform cross-section through a desired length of the channel, producing an indentation in said stock at a region removed from said enlargement, and severing said material at said indentation.

4. The method of forming shaped articles .such as electrical in'sulators from-elongated stock having a channel extending longitudinally therethrough which consists in heating a zone of said stock to a temperature of plasticity, exerting sufiicient endwise pressure on said stock to produce an enlargement atthe heated zone, externally molding said enlargement to desired configuration, SlZlIlg a bore of substantially uniform cross-section through a desired length of said stock, shaping a tapered tip on said stock adjacent one side of the enlargement, trimming the end of the tip to provide a predetermined tip length, and severing the stock on the opposite side of the enlargement so as to include as parts of the detached insulator the enlargement, a shaft adjacent one side thereof and an insulator ti on the opposite side thereof with a bore o desired cross-section extending through the insulator.

5. The steps in the process 9f forming shaped articles of vitreous silica tubing, wherein the stock is heated to fusion at a desired zone and endwise pressure appliedto form an enlargement at said zone, which consists in molding the enlargement andadjacent portions to desired shape and to provide a shaft and a tapered tip on opposite sides of the enlargement respectively and rotating 'said tubing concentrically around a pin of predetermined diameter to form a bore of substantially uniform crossseetion in the finished article extending lengthwise therethrough.

6. The steps in the processof forming shaped articles of vitreous tubing having a channel extending lengthwise therethrough wherein the stock is heated to fusion temperature at a desired zone and endwise pressure applied to form an enlar ement at said zone, consisting of rotating said tubing concentrically about a pin of predetermined diameter to form a bore of substantially uniform cross-section in the finished article, said pin being coated with a lubricant to prevent adherence of the pin with the inner walls of the tubing during rotation of the latter.

7. The method of forming spark plug insulators from elongated stock of vitreous silica having a channel extending lengthwise therethrough which consists in rotating said stock on its longitudinal axis, si-

multaneously heating a zone of said stock A adjacent 'one end thereof to a temperature of plasticity, exerting endwise pressure on said stock to produce an enlargement at said heated zone, shaping said enlargement externally to form a substantially spherical configuration thereon, sizing a bore of substantially uniform cross-section through said enlargement and through portions of said stock adjoining said enlargement, shaping a portion of the stock on one side of the enlargement to provide a tip for said insulator, and severing the insulator thus formed from the stock on the side of the largement whilst preventin collapse of the bore wall, tapering the stoc at one portion thereof adjacent the enlargement, and severing the stock at the untapered portion to provide a shaft for the insulator.

9. The method. of forming spark plug in: sulators from elongated vltreous material having a channel extending lengthwise therethrough which consists in heating a zone of said stock adjacent one end thereof to a temperature of plasticity, exerting endfwise pressure on said stock to produce an enlargement at said heated zone, sizing the channel in the heated portion of the stock to provide a bore for the insulator, shaping the enlargement externally to form c'onvex bearing surfaces thereon, shaping a portion of the stock adjacent the enlargement to form a tapered tip, trimming the tip end to tubing to a temperature of plasticity whilst forming a bore of the required diameter in the heated portion of the channel, forming an enlargement between the ends of the tubing, tapering the tubing below the enlargement, cuttin ofi the tapered endat a predetermined istance below the enlargement, skin heating the tubing at a predetermined distance -above the enlargement, grooving the tubing at this skin heated portion, and breaking off the tubing mechanically at the groove. 1

11. The method ofinaking spark-plug in- I I sulators consisting in heating to p astic ternperature a portion of silica stock having a channel therethrough, upsetting the stock by application of pressure on one endthereof to form an enlargement, producing relative rotary motion at the ends of the heated portion of the stock whereby uniformity of channel cross-section and symmetrical relation of the channel with respect to the enlargement and adjacent portions is secured, sizing the channel through said enlargement and adjacent portions to form a defi nitelbore therefor, shaping the portions adjacent the enlargement, and severing the article thus formed from the stock.

12. The combination of a holding means through which a predetermined'length of elongated stock maybe fed longitudinally,

means for heating a portion of the stock fed through the holding means, mechanism arranged to produce a bore of substantially uniform cross-section in the heated portion of the channel, means for applying an endwise pressure on one end of thestock in the direction of the opposite end to enlarge the diameter of the stock at the heated portion,- 'means for sha ing the a enlargement thus formed, means or tapering thestock below the enlargement and means for severing the v stock between the holding means and the endwise pressure-producing means so'as to include the enlargement and the tapered part in the portion severed from the predetermined' length of elongated stock with the aforesaid bore therethrough.

13. A machine comprlsing a holding means for suspending a predetermined length of elongated'stock with one fixed end "and one free end, means for feeding said stock downwardly, suitable burners arranged to heat a portion of the stock fed throilgh theiholdingvmeans, means for proan-upwardendwise pressure on the free end of' the stock below -.the holding ineans-,;-whe reby an. enlargement-may be pro-,

'duced at the heated portion, means for molding the enlargement'to the desired configuration anddimensions means for tapering theestock 'below-theenlargement, and means-for.-sev.ering-- the .stockabove the enlargement; H trial- A machine 'comprising a holding means I :for-.= suspending a predetermined lengthof elongated stock, means for feeding the .stock '-.through the holding means,

- suitable burners in cooperative relation with 'saida-stock arranged to heat a portion of the sametoifusion temperature, means for rotatingthe stock on its longitudinal axls,

an abutment upon which the lower end of the stock may engage,means for causingthe abutfiltnt 'ito moveupward and produce a longitudinal endwise,. pressure on the stock whereby the heated portion of the latter is expanded and an enlargement formed, means for molding said enlargement to a contour comprising convex bearing surfaces merging with the stock by means of nonangular regions, means arranged to size a bore of substantially uniform cross-section I through the heated portion of the channel,

means for severing the article thus formed from thestock so as to include the enlar ement, and means for actuating the hol er and cooperative mechanisms to perform the 5 operations specified in the desired sequence.

article, means for producing 15. A machine comprising a holder for a predetermined length of stock of vitreous material, a bore-sizing pin in the channel around which the'elongated stock revolves concentrically, means for supporting the pin in fixed relation to the channel, means for heating the stock to its plastic temperature,

means for expanding a portion of the heated means, mechanism for applying endwise pressure on,the end of the stock opposite the hglding means' to form anenlargement, means arranged to size a bore of the reuired cross-section and substantial uniormity through the heated portion of the a tapered tip below the enlargement, a pm arranged to r the sizea bore of reduced cross-section through the tapered-portion ofthe article commu nicating with the first-mentioned bore,

mechanism for externally. shaping the enlargement to provide spherical bearing surfacesmergingwith the stock in non-an ar surfaces, and means for severing the finished article from the stock.

. 17. In combination with an apparatus of character -described for producing shaped articles of vitreous silica having a channel extending lengthwise therethrough a holding means for sustaining a predeten mined length'of vitreous silica stock, instrumentalities arranged to heat the stock to its plastic temperature, a pin having a substantially square cross-section arranged to rotate in the channel in one direction means for rotating the stock about the pin in the opposite direction whereby a bore is sized to predetermined diameter and of uniform crosssection through the article, mechanism for applying an endwise pressure on the end .of the stock opposite the holding means to form an enlargement of the desired configuration and accuracy of dimensions, -means for shaping the stock'below the'enlargement to form a tip, and cooperative mechanism "for ksevering the finished article from the stoc 18. A machine of the class describedvcom prising means for locally heating and sof-. tening elongated silica stock, means for;

forming an enlargement on said stock, means for shaping the softened portion of the stock, a sizing pin adapted to enter the channel and to have relative motion with respect to the stock, means for withdrawing the sizing pin from the stock, and means for detaching the article thus formed from the stock.

19. A machine of the class described comprising means for holding a length of stock,

means for directing suitable flames against a portion'of said stock to fuse said portion,

means for subsequently forming an enlar ement of said, fused portion, means for mo ding the enlargement to a figure partially confined by convex surfaces having the same radii and by other convex surfaceshaving different radii from the first, means for shapf ing an extension of the fused stock below 'the'enlargement, means arranged to size a 'bore of substantially uniform cross-section through the fused portion ing the finished article from the stock. in cluding a shaft of predetermined length above the enlargement, and means whereby all of the aforesaid means are brought into anal out of operation in a predetermined or er.

20. A machine of the class described 06m;

prising means for locally heating and soft tening a length of vitreous stock, means for means for detach- 4 shaping the-softened portion of the stock to 5 provide an enlargement, means for sizing a bore through said stock, and a trimming tool having a shaped surface and a cutting edge for simultaneously shaping and trimming shape the enlargement and adjacent portions of the stock while heated to a plastic temperature, means adapted to indent the skin of the stock circumferentially while said skin is plastic thus securing a weak plane for subsequent breakage, and a hammer and anvil cooperatively related to each other and to the stock whereby the latter may be readily severed at the indentation.

v 22. A machine of the class described comprising means for locally heating and softening a length of stock, means for forming an enlargement on said stock, molding means arranged to shape the enlargement and adjacent portions of the stock, means for sizing a bore of substantially uniform cross-section through the formed article, means for indenting the outer surface of the stock, an anvil cooperating with the stock at the indentation formed by the indenting means, and a hammer cooperating with the anvil and adapted to hit the stock and break it 0d.

23. A machine of the class described comprising means for locally heating and softening a length of stock, having means for .forming an enlargement on said stock,

molding means arranged to shape the enlargement and adjacent portions of the stock comprising rolls, means for heating the base portion of said rolls to minimize the conduction of heat away from the stock, and means for finally breaking ofi the stock thus shaped.

24:. A machine of the class described comprising means for locally heating and softening a length of stock, means for forming an enlargement on said stock, shaping rolls arranged to shape the enlargement and adjacent portions of the stock, means forv bringing said rolls repeatedly into molding relation with said stock, means for auto; matically' heating said stock between suc cessive rolling operations, and means for cutting oil and delivering thelfinished product to a suitable receptacle.

25. In an apparatus for producing from elongated stock, shaped articles having a longitudinal opening therethrough, the comstock, a pin arranged to move into and out of a longitudinal zone or said shaped portion andmeans for producing a difierence in speed of rotation between said stock and said pin.

26. In a machine of the class described, means for locally heating and softening a length of stock, means for forming an enlargement on the heated portion of said stock, molding means arranged to shape portions of the stock adjacent said enlargement comprising rotatably mounted members and means for heating one portion only of said members to minimize the conduction of heat away from the stock, the unheated port-ion of said members having a concave contour which forms a seat for said enlargement.

lln witness whereof, we have hereunto set our hands. a

. lllltVllN 1F. HUUPER.

BERTHQLD F. NIEDERGESASS. PHILIP K. DEVERS.

bination of holding means for suspending elongated stock at one end only, means for heat ng a portion of said stock to plasticity, rolls arranged for shaping externally to a desired contour the plastic portion of the