US2336678A - Lamp sealing apparatus - Google Patents

Description

' Dec. 14, 1943. R. M. GARDNER ET AL I 2,336,678

LAMP SEALiNG APPARATUS Filed July 19, 1941 2 Sheets-Sheet].

Roland M.Ga,z-dnel;. Ralph L. Allen INVENTORS ATTORNEY D 14, 19 3- R. M. GARDNER ETAL LAMP SEALING APPARATUS 2 Sheet s- Sheet 2 Filed July 19, 1941 I Roland M.Ga1'dne1; Ralph .LAuen INVENTORS ATTORNEY Patented Dec. 14, 1943 TENT OFFICE LAMP SEALING APPARATUS Roland M. Gardner, Swampscott, and Ralph L.

Allen, Beverly, Mass,

Electric Products Inc., a

chusetts assignors to Sylvania corporation of Massa- Application July 19, 1941, Serial No. 403,174

6 Claims.

This invention relates to the sealing of vitreous vessels and more particularly to tipping off exhaust tubes of electric gaseous discharge lamps.

This application presents an improvement over the sealing apparatus shown in our co-pending application Serial No. 342,968 filed June 28, 1940, issued November 18, 1941, as U. S. Patent No. 2,262,760.

An object of this invention is to provide the sealing apparatus of the above-identified application with further automatic adjustment features.

Another object is to provide for variations in the wall thickness and the diameter of the tubing being sealed.

A further object is to provide for the proper lcating of the sealing fire in relation to the tip being made, thus minimizing the possibility of the melting glass from being drawn in prematurely.

Another object is to provide a means for maintaining the sealing apparatus in proper horizontal alignment at all times, especially when the apparatus moves in a vertical manner during the course of its operation.

Further objects, advantages and features will be apparent from the following specification taken in conjunction with the accompanying drawings in which:

Figure 1 is a side elevational view partly in section of the lamp sealing apparatus.

Figure 2 is a plan view of the burner support and scissors assembly turned upside down to more clearly bring out the particular structures thereof.

As was pointed out in the co-pending application referred to above, fluorescent lamps are many times evacuated in a position opposite to the position in which incandescent lamps are evacuated, i. e. the fluorescent lamp is suspended from a turret by the exhaust tubulation projecting therefrom. The sealing apparatus of the copending application provided a means whereby fluorescent lamps could be tipped off very readily. However, as was pointed out therein, due to the very nature of the manner in which the lamp is sealed, provision must be made for several types of variances in order to have the apparatus approach a relatively high degree of adaptability.

Therefore it was for the two-fold purpose of enabling the automatic attainment of a finer degree of accuracy and a wider range of adaptability to certain variables that this improved sealing apparatus was invented.

In Figure 1, the fluorescent lamp I has the exhaust tubulation 2 projecting from the center of the re-entrant stem 3. The lamp is held, in the suspended position as shown, primarily through a clamping means located in the head 4 atop the turret 5 of an indexing turret machine. Auxiliary or secondary means for guiding and holding the elongated tubular lamp in the desired position may Well be used. For example a collar similar to element 25 in Figures 1 and 6 of the copending application referred to above may be used to help keep the lamp properly centered in its extension from the point where it is primarily suspended. A secondary holding means 4, similar to the jaw chuck 2! shown in Figure 1 of the co-pending application, should be used because when the main portion of the exhaust tubulation is severed from the lamp by the sealing apparatus, the primary holding means no longer operates and some other means must be available to hold the lamp until it is removed from the machine. This jaw chuck 4| may be located at the ends of a pair of long rods suspended from the turret '5.

The mechanism which actuates this improved sealing apparatus is the same as that described in the co-pending application. The horizontal movement of the sealing apparatus to successively bring it in to encircle the exhaust tubulation 2 and then withdraw to permit the indexing of the machine and the moving of another lamp into sealing position is accomplished by a cam mechanism through a rear lever operating rod similar to rod 40 in Figure 1 of the co-pending application. The vertical movement of this rod is transmitted through the rear lever 6 into the horizontal movement of the sealing apparatus. The vertical movement of the sealing apparatus to successively move the burner shields 7 down into the re-entrant stem 3 while the scaling is actually taking place and then withdraw them therefrom when the sealing has taken place is accomplished by a cam mechanism through the operating shaft 8 which is connected to frame 32 and is located within the operating shaft support 9 similar to shaft 4| and support 42 in Figures 1 and 7 of the co-pending application.

In the sealing apparatus of the co-pending application, certain automatically adjustable features were pointed out. This application contains further automatically adjustable features. As was pointed out in the other application, the burner shields 1 located themselves Within the reentrant stem 3 while the burners 96 heat and melt the exhaust tubulation 2. In the co-pending application, the burners and the scissors-like bafiles of which the burner shields form a part were both mounted on the same element as shown in Figures 1 and 3 of that application. However,

I have found that by mounting them on separate elements a much better seal may be obtained.

Thus as shown in Figure 1 of this application, the burners ID are mounted on the burner sup port H while the scissors l2, of which the semiconical burner shields 1 form a part, are mounted on the scissors support 13. These scissors consist of a pair of individually pivoted plates as shown in Figure 2 of the co-pending application. The burner support I l and the scissors upport l3 are pivotally mounted through the pin M. Thus the burners It! will direct their fire to the same area on the tubulation 2 at all times rather than to various areas as it was inherently necessary for it to do in the type of arrangement shown in the co-pending application.

In the co-pending application, the stretching of the melting exhaust tube to sever the tube from the lamp was accomplished through a downward movement of the entire torch assembly at a pro-determined moment after the burner shields had located themselves within the re-entrant stem. This therefore meant two things, first the burners moved downward and thus the flames therefrom were directed at a different point on the exhaust tube, and second, the heated exhaust tube was being stretched at a pre-determined moment with no regard to the extent or degree to which the tubulation had melted. If the wall thickness and the diameter of all exhaust tubing were uniform, the pro-determined movement for stretching the melting tubing might very well be accurately calculated. Not only is such uniformity uncertain but adaptability of the tipping torch to tubulations having known differences in wall thickness and diameter is desirable. The sealing apparatus herein disclosed possesses such adaptability.

When this sealing apparatus has reached the position in the sealing process where it has centered itself with respect to the exhaust tube 2 and has dropped down to permit the burner shields I to locate themselves within the re-entrant stem 3 and the outer edges of the scissors l2 to rest on the rim of the bulb, the difference in the manner in which the stretching of the heated exhaust tube is accomplished is apparent.

The scissors support l3 on which the scissors l2 are mounted pivots on the pin M. The spring l5 which is held between the burner support H and the scissors support I3 is adjustably attached to the support l3 through the adjustment screw IS. The tension on the spring [5 is capable of exerting a pressure slightly greater than the pressure which the auxiliary or secondary lamp holding means M exerts in holding the lamp. When the heat from the burners ID has heated the exhaust tube 2 sufiiciently to cause it to lose some of its strength and it starts to melt, the expanded spring [5 will slowly contract and the rearward extremity of the scissors support l3, pivoting on the pin M, will move upward and the scissors l2, on the forward extremity thereof, will pitch downward with the result that the lamp I will gradually be severed from the exhaust tube 2, the severing taking place at the rate and at the time when the particular exhaust tube has become sufficiently weakened to permit it rather than at a pre-determined time and rate which may be too soon for one exhaust tube and too late for another.

The adjustment screw I! with the nut [8 thereon enables the establishment of a pre-determined range within which the expansion and contraction of the spring I5 can effectively operate with respect to the movement of the scissors l2 and the burner shields l in effecting a severing of the lamp I from the tubulation 2.

The scissors 12 consists of two separate bafile plates mounted separately in a pivotal manner about the screws l9 through the scissors support l3. The spring 20 is suspended between ,the studs 2| projecting from the bottom of the two baffle plates which constitute the scissors l2. The forward extremity of these baffle plates each have mounted thereon a shield. When the two plates come together these two shields together form a truncated cone with a small opening at the apex thereof through which the exhaust tube may extend. The structure of these plates and shields and the manner in which they are mounted is substantially the same as that shown in the co-pending application, and shown particularly in Figure 2 of the drawings thereof, with the exception of course that the burners in this case are not mounted as shown in the copending application but as shown in Figure 1 of this application.

The stud 22, extending upward from the burner support H projects into the elongated slot 23 in the slide 24. It is about this stud that the burner support II and its adjacent assembly pivots, thus enabling the burner centering plate 25 and the scissors l2 to move slightly to the left or to the right to properly center the sealing apparatus with each individual exhaust tube.

Since the exhaust tube might well vary slightly in length and/or the operator might not project the tubulation 2 up into the head to the normal extent, provision is made therefor on the sealing apparatus.

If the tubulation is short or if the exhaust tube is projected too far up into the head 4, the sealing apparatus, when it drops down to enable the shields l to locate within the re-entrant stem 3 and the outer edges of the scissors l2 to come to rest on the rim of the bulb I, it will move down too far and in all probability break the lamp and the exhaust tube. In the sealing apparatus of Figure 1, when there is a short exhaust tube, the sealing apparatus will drop down, the scissors will come to rest on top of the lamp, the forward extremity of the burner support H will touch the scissors, and any further downward movement will result in the burner support H pivoting about the pin 26 in the saddle 21. Although the main frame of the sealing apparatus will continue to move downwardly, the forward extremity of the burner support II and its related assembly will be pushed upward, said upward movement of the support H being cushioned from striking the slide 24 by the spring 28 which is recessed in the slide 24 and which slides freely on the top of the burner support H. In this manner provision for short exhaust tubes or exhaust tubes which have been projected up too far into the head 4 is made.

Just as provision is made for short exhaust tubes, so too is provision made for long exhaust tubes, This is accomplished through the adjustment screw 29 and the nut 39 in the rearward extremity of the burner support H and the adjustment screw l1 and nut l8 in the scissors support [3. These screws l1 and 29 are set to provide for the longest possible exhaust tubulation in a certain group of lamps being tipped off. Then any exhaust tubing which is shorter than the longest one will cause the mechanism described will halt the forward motion above, in respect to short exhaust tubes to operate. When it is desired to seal a set or series of lamps-having exhaust tubes of a length known to be greater than the length of the exhaust tubes of lamps presently being sealed, the screw 29 through the burner support is loosened so that the entire burner support assembly, pivoting on the pin 26 in the saddle 21 may pitch further downward by reason of its own weight after the end of the downward movement of the entire lamp sealing assembly through the operating shaft 8 has been accomplished and still the scissors I2 has not come to rest on the rim of the lamp I and the shields i have not as yet located themselves within the re-entrant stem 3. This furtherdownward pitching accomplished through the setting of the screw 29 will be suflicient to locate the shields '5 within the stem 3 and the scissors I2 on the rim of the lamp, thus insuring a proper sealing of the lamp from the tubulation at a point below of the lamp.

Provision is also made for irregularities in the vertical alignment of the torch and the tubing in the line of motion of the torch. This is necessary to provide for such exhaust .tubulations which do not project up from the stem exactly perpendicular to the rim of the bulb. If the tubulation is not sealed into the stem perfectly perpendicular thereto, a slight variance therefrom at this point of sealing will mean a greater difference along the length of the exhaust tube at points further removed from the stem, for exampic, at the point thereon at which the scissors i2 first encircle the tubulation. It is to insure the locating of these exhaust tubes within the notch provided therefor at the apex of the truncated cone formed by the burner shields i that the burner support I I is pivoted and mounted through the pin 26 in the elongated slots 33 in the saddle 21.

The spring 3 I, attached to the frame 32 serves to cushion the rearward movement of the burner support I I when the entire sealing apparatus moves back after completing the sealing operaw tion. Thus there is no danger of the burner support II and its assembly being thrown out of alignment as it rides in the saddle 27 for the support II will strike the spring 3i before any jarring contact can be made. forward of the pin 25 is greater than the weight rearward thereof with respect to that portion of the sealing apparatus which pivots thereabout, the burner support assembly will always move forward the maximum amount thus providing for such exhaust tubes as are angularly disposed in a forward direction away from the scissors about to encircle it. If the exhaust tube is angularly disposed in a rearward direction toward the scissors I2, the stop in the burner centering plate 25 of the sealing apparatus as it rides in on the pin 26 in the elongated slots 33. Thus do the elongated slots 33 in the saddle 2? automatically provide for the variations in the exhaust tubes, in respect to their angular disposition in their projection from the stem of the lamp.

As was pointed out above, in the various steps which the sealing apparatus goes through before it has actually located itself in sea-ling position, the sealing apparatus first moves in to encircle the exhaust tubing and then drop-s down to the sealing position flush on top of the lamp. It should be noted that the inward motion is transmitted to the sealing apparatus through the rear the level of the rim Since the weight lever B. If, for any reason, when the inward movement has been completed and the downward movement is about to be imparted through the operating shaft 8, the rear lever 6 is not aligned perfectly parallel with the shaft 8, the downward movement of the shaft 8 will not result in an absolutely straight downward movement of the sealing apparatus but the angularly disposed rear lever 6 connected to the sealing apparatus through the roller 34 in the elongated slot 35 will either pitch the sealing apparatus forward or rearward during this downward stroke. This is highly undesirable because it would tend to decrease the efiiciency of the many automatic adjustments described above.

I have, therefore devised a means for insuring the proper positioning of the rear lever 6 so that it will always align itself for the vertical stroke. Thus no horizontal movement is caused by the rear lever ii during the occurrence of the vertical stroke. The slide yoke 36 in the slide 24 has the elongated slot 3! therein. The adjustment screw 38 extends through the slide 25 into the yoke 36 through the elongated slot 37. This screw is set at that point within the range of the slot 31 which will cause the rear lever 6 to align itself perfectly parallel with the operating shaft 8 after the horizontal movement has been completed and before the vertical movement starts. The adjustment screw 39 projecting from the shaft support 9 provides an additional means for securing this alignment. ihis screw 39 may be adjusted so that it will insure a predetermined spacing between the rear lever 6 and the shaft support 9. Thus the screw 38 is adjusted to secure the parallel alignment and the screw 3. 3 is adjusted to insure the proper spacing of the shaft support from the rear lever 6.

Figure 2 is a view of the sealing apparatus from below. This view was taken in preference to one from the top in order to more clearly illustrate the features differentiating this sealing apparatus from that shown in the co-pending application. It shows the scissors l2 which consists of a pair of baiiies pivoting about the screws [9 in the scissors support I3. It also shows the pair of burner shields I which, when the plates which form the scissors are brought together as shown here, form a truncated cone with the opening 40 at the apex thereof, through which the exhaust tubulation projecting from the lamp I may extend. The spring 20 suspended between the studs 2i serve to bring the jaws of the scissors I2 together after they have been opened to permit the entrance therein of the exhaust tubulation.

The pin It extends through the burner support II and the scissors support I 3. It is about this pin I 4 that the scissors support pivots. The rearward extension of the burner support II pivots and is automatically adjustable along its longitudinal axis through the pin or roller 26 in the saddle 21.

What we claim is:

1. In apparatus for severing the exhaust tube of an electric lamp, the combination: a burner support; burners projecting from said support; a burner shield support mounted on said burner support for pivotal movement about a horizontal axis; and burner shields, each mounted on said burner shield support for pivotal movement about a vertical axis.

2. In apparatus for servering the exhaust tube of an electric lamp, the combination: a burner support; burners projecting from said support; a burner shield support mounted on said burner supporting a lamp and support for pivotal movement about a horizontal axis; burner shields, each mounted on said burner shield support for pivotal movement about a vertical axis; and a spring member mounted between said burner support and said burner shield support as opposition to said pivotal movement of said burner shield support.

3. In apparatus for severing the exhaust tube of an electric lamp, the combination: means for its exhaust tube, said means comprising an exhaust tube gripping clamp and a lamp gripping clamp; a burner support; burners projecting from said support in the direction of said exhaust tube; a burner shield support mounted on said burner support for pivotal movement about a horizontal axis; burner shields, each mounted on said burner shield support for pivotal movement about a vertical axis and having a portion for engaging an end of said lamp; and a spring member mounted between said burner support and said burner shield support as oppositon to said pivotal movement of said burner shield support; said spring having a strength factor greater than that of the said lamp gripping clamp; whereby as the holding effect of the exhaust tube clamp on said lamp is reduced by heat from said burners weakening said exhaust tube, the said spring forces the lamp longitudinally through said lamp clamp through its action on said burner shield support and the endwise engagement of said burner shields with said lamp.

4. In apparatus for severing the exhaust tube of an electric lamp, the combination: a main body; a burner support mounted on said body for pivotal movement about a horizontal axis; burners projecting from said support; a burner shield support mounted on said burner support for pivotal movement about a horizontal axis; and burner shields, each mounted on said burner shield support for pivotal movement about a vertical axis.

5. In apparatus for severing the exhaust tube of an electric lamp, the combination: a main body; a burner support mounted on said body for pivotal movement about a horizontal axis; burners projecting from said support; a burner shield support mounted on said burner support for pivotal movement about a horizontal axis; burner shields, each mounted on said burner shield support for pivotal movement about a vertical axis; a spring member mounted between said burner support and said burner shield support as opposition to said pivotal movement of said burner shield support; and adjustable stop means, mounted on said burner shield support, for limiting the pivotal movement thereof in one direction.

6. In apparatus for severing the exhaust tube of an electric lamp, the combination: a main body; a burner support mounted on said body for pivotal movement about a horizontal axis; burners projecting from said support; a burner shield support mounted on said burner support for pivotal movement about a horizontal axis; burner shields, each mounted on said burner shield support for pivotal movement about a vertical axis; and a horizontally disposed spring member having an end mounted on each of said burner shields with a tendency to oppose movement of said shields away from each other about their respective vertical axes.

ROLAND M. GARDNER. RALPH L. ALLEN.

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