US1701388A - Method of and apparatus for sealing-in incandescent lamps and similar articles - Google Patents

Description

INCANDESCENT H. REMANE METHOD OF AND APPARATUS FOR SEALING-IN LAMPS AND SIMILAR ARTICLES Flled Aprll 1925 Invenror: Hermann Re man y HisArrorneg.

' Patented Feb. 5, 1929.

UNITED STATES 7 1 1 1,3 8 PA ENT OFFICE.

HEBMANN BEMAN'E, OF WINTEBTEUR, SWITZERLAND, ASSIGNOR TO GENERAL ELEC- TRIO COMPANY, A CORPORATION OF NEW YORK.

METHOD OF AND AIPABATUS SEALING-IN INCANDESCENT LAMPS AND SIMILAR ARTICLES.

Application filed April 7, 1925, Serial No. 21,312, and in Germany May 7, 1924.

The sealing-in of the stem into the glass bulb of electric incandescent lamps and sim-' ilar glass containers or vessels by the application of flame and continuous rotation of 5 the parts to be sealed together was, according to previous practice, accomplished by sealing the stem to the neck of the bulb, either at the edge of the neck as in the short neck method,

or else at a point about half way up the neck as in the long neck method. In the latter kind of sealing-in, as shown for example in U. S.

patent to Mitchell and White, 1,453,594, May

- 1, 1923, it is customary to use bulbs with a rather elongated neck. Although the excess length of neck caused a considerable loss of glass, this mode of sealing the parts together was preferred in practice because the sealingin could be done with reater safety and reliability, and the burnef gases from the burner flames did not enter the lamp and thus were prevented from injuring the sensitive metallic parts inside the lamp.

In accordance with this invention, the advantages of the long neck method of sealing the parts together inside the neck instead of at the edge is preserved, in spite of the use of a bulb with a short neck. With this end in view, according to'the invention and before the sealing-in takes place, the short neck of the bulb is gripped at its lowermost edge ina novel manner by the fingers of a gripping device, and the neck is elongated by subjecting it to the action of a pulling member joined to said gripping device, which, after the neck of the bulb has been sufliciently softened by burner flames playing on it, preferably tangentially, moves to elongate the neck, the pulling member being limited in its movement. This pulling movement is dis- 40 continued as soon as the neck has been sufficiently lengthened, and the pulling member then holds the neck by means of the gripping device, without exerting further tension on it. The slight constriction of the'neck produced by capillarity and flame pressure, in

spite of the action of the pulling member, is

not objectionable, and after the pulling stops,

the neck can be safely sealed to the stem, the

excess length of bulb neck being afterwards cut ofi in well-known manner by mechanical action, air pressure, or narrow and pointed flames. Y

- In order to. facilitate the lengthening of the short bulb neck, and to obtain more safely a .and the filament supports 0.

uniform thickness of the wall, a preferable plan is to elongate the bulb neck by stages by passing it consecutively through a number of working ositions.

. The possi ility' afforded by the means pro-Y vided in this invention of sealing-in the stem at a point in the interior of the neck. oven in bulbs with a particularly short neck, offers great economies, making not only for simplification and cheapening of the bulb, but also allowing realization of great savings in glass and cost of transportation of bulbs from the I glass works to the lamp factory where they are to be used. Another substantial advantage of the new scaling-in method is that, on the one hand, crooked sealing-in of the stem is avoided, since the edge of the neck during the sealing of the neck to the edge of the stem is immovably locked in position, while on the other hand, absolute uniformity of wall thickness at the sealing-in points is always insured by virtue of the positive-and limited elongation of the neck ofall bulbs worked consecutively at a number of positions.

The drawing herewith illustrates the rotatable holder head of a sealing-in machine (see which is in gensaid Mitchell and atent 1,453,594, is provided in operator at the loading position, the stem having been previously provided with a filament The bulb' is placed with its neckd downwards, over the filament supports c and the stem 5, the bulb e restin on and being rotated by the rotatable bulb holders ,The neck 03 of the bulb,

is so short that in the first working position of the machine, the edge of the neck preferably somewhat flared protrudes, as shown in Figure 1, only slightly beyond the flare g of the saidstem, and insufiiciently for the sealing-in of the stem, the edge of the flare being substantially at the edge of the bulb neck, as was customary in the short neck method of sealing-in used for many years, but now superseded by the longneck method of seal- '71. carried by a pullin memli er,

ing-in disclosed in Figures 7 to 9 of U. S. patent to Kremenezky N 0. 941,996, November 30, 1909. The edge of the neck of the bulb is gripped peripherally by a gripper, which may conveniently comprise ielding fingers such as the vertically guided forked'frame 2' which is .holder heads are disposed. By means of the said guided frame 71 and the fingers h, the

bulb e is held in position, and its neck is subcaused to move into the next or's'econd workjected to tension by the stationary cam m.

After part of the bulb neck has been adequately heated in the first working osition as depicted, in 'Fi re 1, by means 0 burner flames a prefera ly arranged to strike the bulb neck tangentially, the holder head is .ing position. During its movement into this second working poslton, a strong mechanical .pull is exerted upon the softened neck por- Z of the slot Z in the cam m.

tion by the gripper through the fingers it, since the forked frame 71 and the fingers mounted on it are compelled by the roller is to move slightly downward by the curvature he consequence j of this action, as shown in Fig 2, is that the neck of the bulb issomewhat lengthened, so that the lower ed 9 of the neck now projects somewhat fart er .beyond the edge of flare g of the stem 1). While in this second working position, the bulb neck is subjected to additional heating by tangentially placed burner flames a, and also w ile moving out of this second working positon toward the thlrd positon the neck is further positively lengthened by the further pull of the fingers has the roller is of the forked frame i passes into the curvature Z of the slot Z. The bulb neck after leaving the second workin posipose,in the working position depicted in igedge of the flare.

tion is lengthenedso much that in the ollowing or third working positon sufiicient length has been provided to permit the safe sealingm of the stem into the bulb. For this urure 3, with the neck d of the bulb being, as before, firmly gripped by the fingers h, the bulb neck in the usual way is subjected to the action of radially disposed sealing-in fires or flames a which seal the bulb neckto the The softened portion of the neck located below the flare of the stem may incidentally for instance, as here shown, beplaced firmly and snugly against the circumference of a cone-shaped bushing o of the stem spindle 11. There is then formed a chamber between the edge of the flare and the conical bushing, and in the next working stage, asshown 1n Figure 4,*the surplus neck may be cut ofi in the well known way by softening a narrow zone by. flames a, and also .by a current of air supplied through a verticalbore p of the stem spindle a and directed outwardly by radial holes 9 provided immediately below the sealing-in points, blowing out the softened glass of the neck directly below the sealing-in point until it is thin and is easily severed by the flames. v

After having passed through the unloading positions for removal of the sealed lamp, and a position where the surplus portion of the neck is removed from the stem spindle,

the forked frame 21 with fingers h is again raised by the curved slot Z of the cam into the position shown in .Fig. 1, and the head is,

ready to receive a new bulb and stem.

Instead of severing the surplus neck by.

blowing out the softened glass by an air current the zone on. the neck heated to a high temperature'can be severed in the well known ways as by a toolthrust into the softened material of the. neck immediately below the sealing zone, by tearing off the surplus, or merely by means of pointed flames directed upon the neck.

The elongation of the bulb neck durin the first stage of the working process, w en the bulb neck is down, can also be obtained by loading the pulling device with sufiicient weight, but in this case, it is necessary to lock thepulling device after the desired elongation of the neck has been obtained, in order that the sealing-in may be done in all cases with the stationary.

The elongation of the bulb vneck roduc'ed rior to the sealing-in proper can,-i desired,

pull down device e producedby one singlemechanical pullon changin from one workin position to the other. owever, when sea ing in large bulbs, the elongation 'of the bulb neck may also be effected in more than two working stages. The conical bushing 0 can be" made adjustablein height on the stem spindle a; but, if desired, it 'may also be dispensed with,

if the surplus neck is cut off mechanically or b the aid of pointed flames.

hat I claim as new and desire to secure by Letters Patent of the United States is of the bulb immediately adjacent its edge,

ulling the ed e of the neck away from the reduced ulb to a pre etermined extent to elongate the plastic neck and thereby draw its edge considerably beyond the edge of the stem,-

holding the ed e of said neck immovable with reference to the ulb in the position into which it has been drawn and heating to a higher temperature the hot elongated neck at a zone adjoining the edge'of the stem while the edge no 7 said neck immovable with reference to the.

edge of the bulb, heatin mined'distance to stretch the neck a bulb which comprisesholding the stem inside the' bulb neck with its edge substantially at the edge of the bulb neck, heating the bulb neck along a zone immediately adjacent its edge, gripping the edge of the bulb neck and pulling it away from the bulb a predetermined distance to stretch the hot plastic neck 'over the stem, holding the edge of said neck immovable with reference to the bulb in ,the position into which it has. been drawn, further heating the hot elongated neck along a zone adjoining the edge of the stem while the edge of said neck is 111 said position to seal the stem and the wall of'the bulb neck together, and removing the sur lus neck by severing the bulb neck imme iately below the stem.

3. The method of sealing a stem into a bulb which comprises positioning the stem in the bulb neck with its edgev substantially at the the bulb neck immediately adjacent its e geuntil it is plastic and stretching it to while plastic over. the stem by successive steps until the edge of the neck is considerably beyond the edge of the stem, holding the edge of said neck immovable with referenceto t e bulb in the position drawn and then, while the elongated neck is still hot, and while the edge of said neck is in said position heating a zone of the neck immediately adjacent the edge of the stem to seal .the walls of the elongated bulb neck'to the edge of the stem.

4. The method of sealing a stem into a bulb which consists in positioning the stem in the bulb neck with itsedge substantially'at the edge of the bulb neck, heatin the bulb neck along a zone immediately a acent its edge to render it plastic, seizing the edge and u 1- ing longitudinally of the neck a pre eterover the stem and thin its walls, holding the edge of bulb in the position into which it has been drawn and then while said wallsare' still hot and while the edge of said neck is in said posi- P tion sealing the edge of the stem to thehot thinned walls of the neck.

5. In a device of the character described,

the combination of a bulb holder, a stem holder for holding a stem in-the neck of the bulb with its edge substantially a predetermined extent p into which it has been atthe edge of the neck of the bulb for heating the neck of the bulb in said holder along a zone immediately adj acent its edge, a bulb neck gripper for gripping the edge of the bulb neck and movable with reference to the bulb holder to a predetermined extent sufiicient only to stretch the neck of the bulb over the stem on said holder until said stem is well within but out of contact with the bulb neck and actuating means for moving said bulb neck gripper away from the bulb holder to said predetermined extent only and then holding erence to said holder while said burners seal the walls of the elongatedbulb neck to the edge of said stem. 7

- 6. In a device of the character described, the combination of a head mounted to travel through several positions in succession and comprising a bulb holder, a stem holder, and a gripper for seizing the neck of a bulb in said holder, said gripper being from said holder to carry the edge of the neck of said bulb well beyond the stem on said stem holder, burners mounted at some of said ositions to heat the neck of a bulb in said holder, and actuating means responsive to movement of said head from one position to the next for moving said gripper relative to said holder.

7. In a device of the character described, the combination with a bodily movable head mounted to move into two positions in succession and comprising a bulb holder, a stem holder in registry with said bulb holder and a bulb neck gripper mounted to' move out of its normal position and away from said bulb holder into a remote position to pull the edge of the neck of a bulb in said bulb holder beyond the edge of a stem on said stem holder, of burners mounted at the first position to heat the neck of a bulb in said bulb holder adjacent the stem, sealing-in burners mounted at the second position to direct a flame at and below the edge of the stem, a stationa cam mounted adjacent the path of said hea and connections between said cam and said gripper, said cam bein shaped to move said gri per from its normal position to its remote osition during travel'o said head from the first position to the second and to hold it in in said bulb holder, burners movable away remote position during the sealing-in of the I stem. 7

In witness'whereof, I have hereunto set my hand this 18th day of March, 1925.

HERMANN REMANE.

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