US3399984A

US3399984A - Machine for forming helical grooves in thin wall galss tubing

Info

Publication number: US3399984A
Application number: US399967A
Authority: US
Inventors: Donald G Trutner; Andrew H Olsen
Original assignee: Duro Test Corp
Current assignee: Duro Test Corp
Priority date: 1964-09-29
Filing date: 1964-09-29
Publication date: 1968-09-03
Anticipated expiration: 1985-09-03

Description

Sept. 3, 1968 D. G. TRUTNER ET AL 3,399,934

MACHINE FOR FORMING HELICAL GROOVES IN THIN WALL GLASS TUBING 8 Sheets-Sheet 1 Filed Sept. 29, 1964 ATTORNEYS m Han 5... mm m m S. ovm mo a: M an m t I w 1 T 8 v 2 #N 8 m2 8 NE 3 N8 8 mH 1 f 4 m 55 5:2 55 2.53 wzifizuE @2385 32% @5392:

Sept. 3, 1968 o. c. TRUTNER ET AL 3,399,984

MACHINE FOR FORMING HELICAL GROOVES IN THIN WALL GLASS TUBING Filed Sept. 29, 1964 8 Sheets-Sheet 2 Sept. 3, 1968 o. e. TRUTNER ET AL 3,399,984

MACHINE FOR FORMING HELICAL GROOVES IN THIN WALL GLASS TUBING Filed Sept. 29, 1964 a Sheets-Sheet 5 FIG. 5 96 I02 'MIMWIIIJT" INVENTORS DONALD G. TRUTNER ANDREW H. OLSEN ATTOR EYS Sept. 3, 1968 D. G. TRUTNER ET AL 3,399,984

MACHINE FOR FORMING HELICAL GROOVES IN THIN WALL GLASS TUBING 8 Sheets-Sheet 4 Filed Sept. 29, 1964 R E 7//////////// m w mwm m V NT R Q n H M m. md/ ul. WOW ,v M llL {I}! I L 8 L MD mm \1 mm E o FziflregF I Sept. 3, D. G. TRUTNER ET AL MACHINE FOR FORMING HELICAL GROOVES IN THIN WALL GLASS TUBING Filed Sept. 29, 1964 8 Sheets-Sheet 5 INVENTORS DONALD G. TRUTNER ANDREW H. OLSEN ATTORNEYS S pt- 3, 1968 D. a. TRUTNER E 3,399,984

MACHINE FOR FORMING HELICAL GROOVES IN THIN WALL GLASS TUBING Filed Sept. 29, 1964 8 Sheets-Sheet 6 FIG. 8

HIIHIM \llllllilu nlmllhh; N

INVENTORS I DONALD e. TRUTNER 1| ,,|l ANDREW H. OLSEN ATTORNEYS Sept. 3, 1968 Filed Sept. 29, 1964 FIG.

D- G. TRUTNER ET AL MACHINE FOR FORMING HELICAL GROOVES IN THIN WALL GLASS TUBING 8 Sheets-Sheet 7 INVENTORS DONALD G. TRUTNER BY ANDREW H. OLSEN ATTORNEYS Sept. 3, 1968 D. G. TRUTNER ET AL 3,399,984

MACHINE FOR FORMING HELICAL GROOVES IN THIN WALL GLASS TUBING Filed Sept. 29, 1964 8 Sheets-Sheet 8 INVENTORS DONALD G. TRUT R ANDREW H. EN

ATTOR ZEYS United States Patent 3,399,984 MACHINE FOR FORMING HELICAL GROOVES IN THIN WALL GLASS TUBING Donald G. Trutner, Chatham, and Andrew H. Olsen, Jersey City, N.J., assignors to Duro-Test Corporation, North Bergen, N.J., a corporation of New York Filed Sept. 29, 1964, Ser. No. 399,967 20 Claims. (Cl. 65-285) ABSTRACT OF THE DISCLOSURE A machine for forming one or more grooves in the wall of a glass tube in which the tube is automatically transferred to the groove-forming station and from the groove forming station.

The novel subject matter herein disclosed involves a machine and method, by means of which one or more helical grooves are formed simultaneously in a plurality of thin walled glass tubes.

Such formed tubes are suitable as the envelopes for fluorescent lamps.

The substance of this disclosure will gradually be developed in connection with the following detailed disclosure of the single embodiment of the machine selected for illustrative purposes, as hereinafter described in connection with the attached drawings thereof and the subsequent description of the operation of the machine. The method will also become apparent in the same manner.

In the accompanying drawings:

FIGURE 1 is a side elevational view, with some parts broken out in order to permit the illustration of the complete machine in its overall appearance;

FIGURE 2 is a plan view of the machine of FIGURE 1;

FIGURE 3 is an enlarged cross sectional view in the loading area of the machine, taken on the line 3-3 of FIGURE 2;

FIGURE 4 is a cross sectional view, taken on the line 4-4 of FIGURE 2 in the preheating zone of the machine;

FIGURE 5 is an enlarged vertical longitudinal cross sectional view through one of the tube supporting rollers in the preheating zone, illustrating the manner in which expansion thereof due to heating is accommodated;

FIGURE 6 is an enlarged side elevational view of the machine in the region between the preheating zone and the grooving zone with omission of details not sought to be disclosed herein;

FIGURE 7 is a cross sectional view taken on the line 77 of FIGURE 6;

FIGURE 8 is a plan view of the portion of the machine at which the groove forming torches are mounted;

FIGURE 9 is an enlarged side elevational view of several of the torches and related mechanism showing the manner of supporting the glass tubes and the way in which more than one, for example, two, grooves circumfe'rentially spaced may be simultaneously formed in the wall of the glass tube;

FIGURE 10 is a cross sectional view taken on the line 10-10 of FIGURE 9, showing the structure of one of the torches;

FIGURE 11 is a cross sectional view taken on the line 11-11 of FIGURE 10, showing other details of the torch structure.

The machine, in a functional sense, may be subdivided into four sections, which as indicated in FIGURE 1 comprise the loading area, that is the input end of the machine. The next area sequentially speaking is the preheating area, where the thin wall glass tubes are heated to temperatures which prepare the tubes for the grooving operation. The next area comprises the spiral grooving portion of the machine where the glass tubes, while they continue to be heated in a manner similar to that in the preheating area, are also subjected to the groove forming operation. The final area of the machine is designated as the unloading area, at which the grooved tubes are received and from which they are transferred to annealing lehrs.

Describing the loading area in more detail, it is, in a structural sense, quite simple, comprising a suitable table or supporting framework 10 having a series of locating members 12, into which the thin wall glass tubes T are placed to insure proper positioning for transfer thereof to the preheating area. As illustrated, the members 12 are U-shaped channels extending longitudinally of the machine and secured to the platform, so as to properly align the tubes for subsequent movement into the preheating zone.

The main supporting structure for the preheating and grooving sections of the machine consists of a framework of suitable structural members, which is generally rectangular in elevation and plan. This framework comprises

upright columns

14 and 16, which are cross connected by a series of cross braces CB and connected longitudinally by a series of stringer members S. The

members

14, 16, CB and S can be angle irons and channels, as illustrated, interconnected in any suitable manner, as, for example, by welding to form a rigid framework. Extending longitudinally of this framework along the opposite sides thereof are the

angle members

18 and 20, the edge of one flange of each forming guide rails, on which a movable carriage assembly can travel. A carriage assembly of sufiicient length is illustrated in FIG. 3, including as a sub-assembly 22 having transverse supporting member 56 extending at right angles to the

rails

18 and 20. The member 56 is supported on the

rails

18 and 20 by means of

rollers

24 and 26 connected to the member by uprights 24' and 26'. The roller 24 is grooved so as to hold the frame against transverse movement on the rails.

Pivotally mounted at 28 on the member 56 are bell crank levers 30, one end of each bell crank lever being pivotally connected at 34 to a single link 32. This link is connected by another link 36 from one of the pivot points 34 to one end of a lever 38. The lever 38 is mounted on and secured to a shaft 40, which extends longitudinally of the machine to a termination point on the member 58, see FIG. 7. The end of the shaft 40 at the position in FIG. 3 is journaled in a bearing mounted on the member 56. For most of its length the shaft 40 is enclosed by a heat protecting tubular shield 50, which terminates at the fire carriage 22", see FIG. 8. The lever 38 is pivotally connected at its other end to a piston rod 42 of a fluid pressure engine 44, the cylinder of which is pivotally supported at 46 on the standard 48.

In passing it may be noted that the element IB is the instrument and indicator board, on which has been diagrammatically illustrated various instr-umentalities associated with the instrument board. As will be seen in FIG. 2, there is a blank area CH, which is the region in which additional control devices and the multitude of piping required is mounted.

However, these parts of the machine related to the more or less automatic control of the machine are not disclosed, as not being of importance to the subject matter herein sought to be protected.

As illustrated in FIG. 7, the end of the shaft 40 at this position is journaled on the transverse support member 58 of the sub-assembly 22' and provided with a lever 60, which is pivotally connected by a link 62 to the link 64, which in turn pivotally interconnects each of the bell crank levers 66 at 68. The bell crank levers 66 are pivotally mounted on the member 58 to 70. The sub-assembly 22' is supported from and below the fire carriage assembly 22", see FIG. 7. Although not shown in detail in the drawings, there is another sub-assembly 122, see FIG. 2, including a set of bell crank levers 266, also operated by the shaft 40. The linkage system for operating the bell crank levers 266 is the same as that shown for bell crank levers 30 and 66. The position of the bell crank levers 266 in relation to the other bell cranks 30 and 66 can be seen in FIGS. 1 and 6. It can be noted, as in the case of the showing in FIG. 1, that the free ends of the bell crank

lever

66 and 266, as is true of the bell crank levers 30, can be swung down into alignment with the ends of the glass tubes T by rotation of the shaft 40.

Referring now to FIGURES 1 and 6, mounted on the machine frame is a long fluid pressure engine 72, whose piston rod 74 is provided at the end with a rotatably sup ported grooved wheel 76. A cable 78 has one end anchored at the fixture 80 on the 'frame and extends therefrom around the wheel 76, around a similar wheel 82 rotatably mounted on the frame and again around a similar wheel 84 pivotally mounted on the frame, and is connected to the other carriage 22 at the bracket 86. As the piston rod 74 is extended, see FIGURE 1, it requires guidance and this is provided by a channel member 75, see FIGURE 6.

Supported in the preheating area on the framework of the machine below the plan of carriage travel are the pre' heaters, which include the open top casings 88. There is one of these preheater casings for each tube to be processed, of which, in the case illustrated, there are four. It will be apparent as the disclosure proceeds that less or more than four tubes can be processed at once. However, in the machine illustrated provision is made for the simultaneous processing of the groups of tubes, each group comprising four tubes T. The bottom walls 90 of the casings 88 are perforated for the admission of ambient air and positioned above those bottom walls are perforated bafile walls 92. Mounted above the bafiie walls are the heaters 94, which have only been indicated diagrammatically because they are, per se, known in the art. These heaters are of the gas burner type and are constructed to provide ribbon flames which extend longitudinally of the machine and have a length sufficient to supply heat, as diagrammatically illustrated at H, in the form of a long band or ribbon to the tubes T. In order that the heated atmosphere from the burners, which is directed upwardly, shall be as quiescent as possible and not disturbed by ambient air conditions, the casings 88 receive air for combustion purposes through the

perforated walls

90 and 92.

Supported at the open top of each casing 88 are pairs of parallel rollers 96, which are mounted in suitable bearings 99 to permit rotation thereof. These rollers are spaced so as to support the tubes T as shown and to provide elongated channels, through which the heat can reach the lower exposed surfaces of the tubes T. These tubes are caused to rotate, by reason of the fact that the rollers 96 are power driven in the same direction to cause the tubes T to revolve. Supported by the carriage assembly by means of tubular members 97, are the hoods 98, which extend along the tops of the casings 88. By reason of their support from the carriage assembly, see FIG. 6, they travel with the carriage assembly longitudinally of the tubes T, rollers 96 and housings 88.

As illustrated in FIG. 5, the rollers 96 comprise metal tubes 100, which have annular surface grooves so that the tubes T are supported at longitudinally spaced points. The metal tubes 100 are made in three parts, which as illustrated in FIG. for one connection, are connected by means of two slip connections, which effect conjoint rotation thereof while permitting longitudinal expansion without buckling due to heating. Thus, the left hand tube section 100 is provide-d with a fixture 102 having an elongated end 104 of reduced diameter, which cooperates 4 with the fixture 106 supported in the adjacent end of the other tube section 100. The reduced end 104 is provided with ribs 108 forming a spline connection with grooves in the fixture 106. It will be seen then that the left and right tube sections can have relative axial movement with respect to each other while insuring their conjoint rotation.

In order to not have too much of a gap between the adjacent ends of the tube sections 100, a small fixed section 101 is positioned at the bearing 103 for the end 104 of reduced diameter of the fixture 102 in the space between the tube sections, so as to peripherally bridge the gap and support the glass tubes T in this region. The pipe FL which appears in FIGURE 1 is the fuel line for the burners 94.

The roller pairs are power driven by a suitable drive system, such as, for example, that shown in detail in FIG. 7 for driving the roller pairs 196, and described below.

The roller pairs 196 are power driven, by means of spur gears 110, see FIGURE 7, secured to their ends. Each pair of spur gears 110 meshes with an associated driving gear 112, which is secured to the same shaft as the worm wheel 114. Each of these worm wheels is driven by a worm 116 mounted on a shaft 118, journaled for rotation in bearings as shown and provided with a driving sprocket 120. This driving sprocket is connected by a chain 122 with a sprocket 124. The sprocket 126, driven with sprocket 124, is connected by a chain 128 to a sprocket 130, secured to the same shaft as the bevel gear 132, which shaft is journaled for rotation in bearings as shown. The bevel gear 132 cooperates with the bevel gear 134 secured to the end of the lead screw 142, see FIG. 6, journaled in bearings on top of the machine frame, as illustrated in that figure. The shaft for the sprockets 124 and 126 is driven through a suitable gear train, not shown but mounted in a housing 141, see FIG. 7. The input shaft of this train is driven by a pulley 138, in turn driven by a belt from any suitable source, such as an electric motor, not shown.

The lead screw 142 effects the progressive movement of the connected carriages 22 and 22' along the rails through the agency of a half-nut, which is supported from the instrument board IB. The rate of travel of the carriage assembly in relation to the rate of rotation of the glass tubes T can be varied by making the sprocket wheel 124 interchangeable with sprocket wheels of other sizes, so as to make the carriage move more slowly or more rapidly, depending upon the desired pitch of the grooves to be formed in the glass tubes, as will be explained later.

The half-nut 144 is mounted on the end of a lever 146, which is pivotally mounted at 145 on a fixture 143 carried by the instrument board IB. For emphasis and clarity it is noted that the instrument board is mounted on the carriage assembly to travel back and forth with it. Intermediate its ends the lever 146 is pivotally connected to the piston of an air engine 148, pivotally mounted at its upper end on an arm 150. This arm is secured to the upper end of a standard mounted on the fixture 143.

The fire carriage 22" includes a plate 55, see FIGS. 7 and 8, which forms a support for the burners or torches T1, of which, in the case of this machine, there are four. The fire carriage is connected to the tube 50, see FIGS. 8 and 9. The plate 55 has attached at its sides the angle iron braces 52 and 54 and on the

rails

18 and 20 by

rollers

24 and 26. Associated with the plate 55 is a similar plate 55a, on which are supported a second group of burners or torches T2. The plate 55a is connected to the plate 55 by means of bolts 55b, which pass through slots in 55a, so that the longitudinal position of the torch group T2, with respect to the torch group T1, can be adjusted. The torches are supported from these plates by means of a universally adjustable assembly, each of which includes a support block 162, see FIGS. 7-10, which block can be adjusted transversely of the carriage in jibs J. This adjustment is effected, see FIG. 10, by means of a threaded adjusting screw 166, rotatably mounted in a fixture 164.

With this screw the block 162 can be moved back and forth transversely of the carriage travel. Passing through the block 162 for up and down movement is a sleeve 168, to which is clamped an arm 174, so that the sleeve can be moved up and down by means of the nuts 172, which engage the threaded rod 170 extending upwardly from the block 162. At 180 is a knurled knob connected to a threaded shaft 178, which lies within the sleeve and has a threaded connection with a support fixture 176. Depending from the sleeve 168 is an arcuate fixture 182, which provides through the pins 184 pivotal support for the jacket 186 of the torch 190. The torch 190 is pivotally connected by a link 192 with the fixture 176. The jacket 186 surrounding the torch provides for water cooling the torch and hence water cooling supply and

exhaust ducts

195 and 196 are shown connected thereto. Mounted in the jacket between the ports of the

connections

195 and 196 is a bafiie member 201, which causes the cooling fluid to flow around the torch 190 in a clockwise direction, as indicated in FIGURE 11. At 194 is a fuel supply connection for the torch 190. It may be explained here that the structure of the torch itself forms no part of this invention.

In order not to have to refer to it later, it is noted that the structure shown in FIGURE provides for universal adjustment of the position of the torch. The main support block 162 for the assembly can be adjusted transversely of the carriage travel by the screw 166. The vertical position of the torch can be adjusted by moving the sleeve 168 up and down by means of the nuts 172. The angular position of the torch in a vertical plane can be adjusted by the knurled knob 180, which moves the fixture 176 up and down and thus tips the torch on the pivot pins 184. The

connections

194, 195, 196 must be sufficiently flexible to permit these movements. The pipe 200 provides means for blowing cooling air into a groove being formed by the torch to control the size of the groove, as will be explained in more detail later. It can be noted in passing that the glass tube T will rotate in a counterclockwise direction and that the flame from the torch will impinge on the glass tube prior to the impingement of the air stream from the pipe 200 as a result.

Returning to FIG. 8, it will be seen that the torch groups can be relatively positioned longitudinally of the carriage travel and the purpose of this will be explained later. It should also be noted that all the torch assemblies are similar in construction.

By referring to FIG. 9 it will be seen that the hoods 98 terminate in the region of the arm 86. Spaced longitudinally therefrom are a series of hoods 198 corresponding to the hoods 98 supported by members 202. The members 202 are connected to the hood supports 197 and are provided with rollers to move on the

rails

18 and 20. The space between these hood sets provides the region in which the torch groups T1 and T2 are positioned, as clearly illustrated in FIG. 9.

Referring to FIG. 1, in the grooving area of the machine, heating assemblies 188, corresponding to those in the preheating section of the machine, are supported on the machine framework. Here again there are four of these, one for each glass tube T. The hoods 198 operate in association with these heaters. As indicated in FIG. 7, the roller pairs 196 are supported above the heaters 188 in the same relation thereto as the roller pairs 96 bear to the preheaters 88.

In passing, it may be noted that mounted on the 22", see FIG. 8, in alignment with the torch groups are two sets of microswitches MS, which cooperate with sets of fixed cams C1 and C2 supported on the top of the machine frame in a position to actuate the microswitches at each end of the carriage travel.

The above described arrangements for supporting the hoods 198 provides a sub-assembly 122", which is tied to the fire carriage 22" by means of a link 300, see FIGS. 2 and 9. Thus, all the sub-assemblies move back and forth on the rails as a unit to function as will be described in more detail later.

At the unloading area is a conveyor assembly 240 for delivering the tubes T at a path at right angles to the path of movement through the machine to an annealing lehr, as previously mentioned, which forms no part of this invention.

The helical grooves are formed in the tube as the carriages move freely from left to right. As can be seen in FIG. 6, when the carriage assembly has moved far enough to the left to place the grooved tubes T on the conveyor 240, the half-nut 144 has moved out of position to engage the lead screw 142. As a result, there is provided at 250 an air cylinder, see also FIG. 1, with a pusher head 252 on the end of its piston rod. Mounted on the end of the second carriage is a bracket 254 positioned to engage the pusher 252 at the end of the transfer of the tubes to the conveyor 240. In order to return the carriage assembly to the starting position for groove formation, air is admitted to the cylinder 250, causing its piston rod to extend, and through the engagement of the head 252 and the bracket 2554 the carriage assembly returns to the starting position, at which time the half-nut 144 will be in a position to be engaged with the lead screw 142.

For emphasis it is noted that the tube connects the

sub-assemblies

22, 22, 122 and fire carriage 22" together to form the carriage assembly to which the sub-assembly 122" is connected by the link 300.

A description of the process for treating a group of glass tubes will now be given in detail. Among other uses, the purpose of this machine is to form one or more helical grooves by deforming the wall of a thin wall glass tube, to cause it to sag inwardly along a helical path. A glass tube suited to this purpose is a tube such as forms the envelope for a fluorescent lamp. An operator places four such glass tubes, in the case of the machine illustrated, on the positioning channels 12, see FIG. 3, by hand. In a fully automated machine this could be done by mechanized loading equipment. At this point the carriage assembly is in its furthest right hand position, as illustrated in FIGS. 1, 2 and 3. Air under pressure is delivered from the instrument board, either automatically or by hand operation, through the line AL, see FIG. 1, to the lower end of the cylinder of the pressure fluid engine 44, causing the piston rod thereof through its connection 42 to effect clockwise rotation of the lower end of the bell crank lever 38. This causes the link 32 through the'link 36 to move to the left, swinging the free ends of the bell crank levers 30 downwardly in a counter-clockwise direction from their retracted position so as to lie across the ends of the four tubes T. Air under pressure is then supplied manually or by a controlled device to the left hand end of the cylinder of the pressure fluid engine 72, see FIG. 1, pulling the piston rod 74 into the engine until it returns to the position shown in FIG. 6. This causes the carriage assembly to move to the left a sufiicient distance so that the glass tubes T are moved axially into the preheaters 88, so that they rest upon the rotating rollers 96. The supply of air to the pressure fluid engine 72 is then cut off and the carriage assembly comes to a stop. The abutment 254 on the carriage assembly is then contacting the end of the piston rod 252, see FIG. 6. As mentioned above, air is then supplied to cylinder 250 so that the carriage assembly is returned to the position to start groove formation in the group of tubes T on the rollers 196 in the grooving area. At this time the half-nut is above the left hand end of the lead screw 142, ready for engagement therewith.

Air under pressure is then supplied to the upper end of the cylinder of engine 44, see FIG. 3, to swing the bell crank levers 30 back to their retracted position.

With the carriage in this position the group of torches T1 are positioned opposite the left hand ends of the previous group of glass tubes T, ready to begin the grooving operation. It is understood, of course, that the preceding group of tubes T are supported over the heaters 188 on rollers 96. These tubes which arrive in a preheated condition from the preheater are maintained at the preheat temperature in exactly the same way by the heaters 188. They are revolving as before on the rollers which support them. Fuel is then supplied through the lines 194 to the torches of group T1 and heat is applied from each of the torches to the associated glass tubes T in a limited area, as can be gathered from FIGURE 10. In passing, it is noted that cooling water is circulating through the

lines

195 and 196 and the cooling case 186 of each torch to prevent the torches from overheating.

Compressed air is supplied to the upper end of a cylinder 148, see FIG. 7, causing the half-nut 144 to move down into engagement with the lead screw 42. On completion of the return movement of the carriage assembly to the starting position through the microswitches MS and the cooperating stationary cams C, solenoid valves are operated to supply fuel to the torches which are auto' matically lighted.

The lead screw is revolving, being driven by a motor, not shown, through the belt 140, pulley 138, gear transmission 141, sprockets 126, chain 138, sprocket 130 and bevel gears 132 and 134. The rollers 96 in the preheaters 88 are driven from the same power source as the rollers 196, or, if desired, from a separate power source by means of a mechanical transmission like that shown for the rollers 196. The drawings have been simplified in this respect by omitting a repetition of the drive for the rollers 96. The speed ratios for the two drives are such that the rollers 96 in the preheater rotate faster than the rollers 196 in the groove forming area. It is appropriate also to note here that the two sets of rollers are grooved to increase the exposure of the glass tubes to the heat from the preheaters 88 and the heaters 188.

When the half-nut engages the lead screw the carriage assembly begins to move to the right at a predetermined speed with respect to the speed of rotation of the glass tubes T in the grooving area. The flames from the torches playing on the surfaces of the glass tubes in a limited area determined by the size and shape of the flames, soften the glass along a helical path to form the grooves (one for each tube) indicated at G1 in FIGURE 9. Thus, heat is applied to each glass tube in a heated region along a line lying approximately in the plane of the axis of the tube, so as to soften the glass wall of the tube. As the tube continues to revolve, the softened glass sags inwardly to form the groove. In order to control the size of the groove, that is the extent to which the glass sags along the helical path, a controlled volume of air is blown into the groove through the tube 200, see FIGURE 10, chilling the glass sufficiently to produce a groove of predetermined depth. The carriage assembly continues to travel towards the right hand ends of the tube group. If a second groove,

for example, is desired displaced circumferentially 180 with respect to the first groove, this is accomplished by the second torch group T2, which group trails the first torch group by a predetermined and preadjusted distance. Thus, when the torch group T2 reaches the point of energization of the torches, they will begin to play flames on the tubes which are displaced 180 from the point of application of heat by the first group. As a result a second helical groove, which is indicated at G2 in FIGURE 9, will begin to form in each tube. It is, of course, apparent that if a third groove is to be formed there would be a third group of torches trailing the other two groups. At this point it will help to refer to the adjustments for the torches which are provided and which have been detailed above. One of these adjustments is related to the fact that the torch group T2, see FIGURE 8, is mounted on a separate supporting plate 550, which can be longitudinally adjusted and locked in place with respect to the torch group T1 mounted on the plate 55. This longitudinal adjustment makes it possible to predetermine the circumferential spac- Cit ing of the starting points of the grooves and hence of the relationship between the tubes G1 and G2. As suggested above, with two grooves a 180 displacement provides a symmetrical structure. If three grooves were formed there would be a 120 displacement between each. However, for an asymmetrical structure the spacing could be such that there could be other angular displacements between the grooves.

In addition, in order to insure the impingement of the torch flames at the exact and most eflicient points of application to the glass tubes T, other and more precise adjustments are possible, see FIGURE 10. These adjustments include the vertical positioning of the torch with respect to the glass tube by actuation of the nuts 172. Through their actuation the torches may be moved up and down on a vertical axis. The angle of impingement of the torch flames, with respect to the horizontal, is determined by rotation of the knurled knob 180. As the knob is rotated in a clockwise direction the carrier 176 will ascend and increase the angle of inclination of the torch to the horizontal, and of course the reverse will happen upon counterclockwise rotation of the knob 180. Finally, the distance between the torch and the glass tube can be finely adjusted by means of the thumb screw 166, causing the block 162 to move in a plane at right angles to the axis of the tube T. Thus, it will be seen that the exact positioning of each torch individually can be effected.

As each torch group reaches the end of its travel adjacent the right hand end of each glass tube, its fuel supply will be cut off to end the grooving operation. Thus. the torches T1 will be shut down first and the torches T2 second. The carriage assembly continues to travel to the right until the bell cranks 30, see FIG. 3, bell cranks 66, see FIG. 7, and bell cranks 266, see FIG. 1, are just beyond the ends of the groups of glass tubes in the loading, grooving and pre-heating areas. This position is shown in FIGURE 1. At this instant compressed air is supplied to the lower end of the cylinder of engine 148, FIG. 7, disengaging the half-nut 144 from the lead screw, bringing the carriage assembly to a stop. At this time the piston rod 74 of the pressure fluid engine 72 will be extended as shown in FIG. 1. Compressed air is now supplied to the lower end of the air engine 44, see FIG. 3, rotating shaft 40, causing the bell cranks 30, 66 and 266 to move down over the ends of the tube groups in the loading area, the preheating area and the grooving area. Air is then supplied to the left hand end of the air engine 72, withdrawing the piston rod 74 into the cylinder and pulling the carriage assembly all the way to the left, see FIG. 1, through the cable connection 78. As a result, a fresh supply of tubes is delivered from the loading platform 10 into the preheaters 88. The previously preheated tubes in the preheater 88 are transferred to the heater 188 in the grooving area. The previously grooved set of tubes in the grooving area are transferred to the conveyor 240. All of these transfers are simultaneously effected by the movement of the carriage assembly from the right hand position shown in FIGURE 1 to an extreme left hand position, at which, as shown in FIGURE 6, the bracket 254 on the carriage assembly engages the pusher 252 of the air engine 250. Thereupon compressed air is supplied to the engine 250, see also FIGURE 1, moving the carriage assembly back to the position where the half-nut 144 can engage the lead screw 142, as previously explained.

The machine is now ready to start the grooving of the new set of tubes that have been placed over the heaters 188. These heaters are used for the purpose of maintaining the preheated tubes received from the preheaters substantially at the temperature whcih they attained in the preheaters. This, of course, makes it possible for the torches to effect groove formation more rapidly and with a minimum of additional heating.

Only brief reference has been made to the cam assemblies C1 and C2, see FIGURE 2, and the microswitches, because there is no effort here to develop further the extent to which the machine may be automated. The initiation of the various operations, such as the movements of the carriers, the movements of the bell cranks 30, 66 and 266, the actuation of the torches and the energization of the various fluid pressure engines in the proper directions are effected precisely at the proper intervals through the cooperation of the microswitches MS with these cam assemblies. It will be noted, because it is shown in FIGURE 8 that the microswitches MS are arranged in two groups, respectively mounted on the relatively

positionable plates

55 and 55a, so as to effect proper coaction of the microswitches with the cam assemblies C1 and C2 which are fixed on the frame assemblies, although, as one skilled in the art would understand, the various cams of the assemblies may have provision for individual, independent, relative positioning, as operating conditions require. Also, in passing it is noted that various controllers and gauges, only a few of which are shown, and even then diagrammatically, are mounted on the instrument board, which, in turn, is supported on the carriage assembly and moves with it. Also, it is noted that the

hoods

98 and 198 are supported from the carriage assembly, so as to move with it, which is necessary in order that these hoods not be in the way of the transfer of the various tube groups from one area to another. Their function, of course, is to reduce the amount of heat lost to the atmosphere and to thereby contribute to maintaining as uniform heating conditions as is possible under the circumstances.

From the above description it will be apparent to those skilled in the art that many details of the construction of the machine selected for illustrative purposes can be varied without changing the scope of novelty of the invention herein disclosed. It is intended, therefore, that the scope of protection afforded hereby be determined by the appended claims rather than to be limited to the selected embodiment of the invention herein illustrated.

What is claimed:

1. Apparatus for processing the wall of an elongated glass tube comprising a pair of elongated rollers for supporting the tube along a substantial portion of its length, at least one of said rollers formed with groove means to provide a heat flow path, and means for providing an elongated heat source coextensive with the groove means and positioned adjacent the rollers whereby the tube supported on the rollers is heated by the heat flow through the groove means.

2. Apparatus as in claim 1 further comprising means on at least one of said rollers to permit longitudinal expansion and contraction thereof.

3. Apparatus as in claim 2 wherein said means for permitting longitudinal expansion and contraction of the roller comprises a series of spaced sections having a slip joint connection.

4. Apparatus for processing the wall of an elongated glass tube comprising roller means for engaging the tube along a substantial portion of the tube length, said roller means including a roller formed by a series of spaced sections having a slip joint connection for permitting longitudinal expansion and contraction of the roller upon heating, and means positioned adjacent the roller means to heat said tube, said roller means having a plurality of grooves therein to permit the heat to flow therethrough from the heating means to said tube.

5. Apparatus as in claim 1 wherein said groove means comprise annular grooves.

6. Apparatus for forming a groove in a glass walled tube in a direction generally along the longitudinal axis of the tube comprising first means for supporting the tube, second means located generally in line with said first support means and the longitudinal axis of the tube for supporting and rotating the tube, heating means positionejd adjacent said second support means for forming the groove in the tube, carriage means, means for reciprocating said carriage generally along the longitudinal axis of the tube from said first support means toward said second support means, and first engaging means mounted on said carriage for engaging the tube during reciprocation of the carriage from the first to the second support means to deliver said tube from said first support means to said second support means.

7. Apparatus according to claim 6 wherein said first support means is located at a pre-heat station which further includes means for pre-heating the tube.

8. Apparatus according to claim 6 wherein said tube is slid from said first support means to said second support means while being in engagement at all times with at least one of said support means.

9. Apparatus as in claim 4 wherein said roller means comprises a pair of rollers for supporting the tube with a space therebetween through which the heat of the heating means flows.

10. Apparatus as in claim 1 further comprising means for forming a groove in said tube in a direction generally along the longitudinal axis thereof.

11. Apparatus as in claim 10 wherein said groove is formed simultaneously with the heating of said tube.

12. Apparatus as in claim -6 wherein said first engaging means comprises at least one finger, and means for extending said finger from said carriage.

13. Apparatus as in claim 6 further comprising second means mounted on said carriage for engaging said tube to move it from said holding means to a subsequent station.

14. Apparatus as in claim 13 wherein said second engaging means comprises at least one finger and means for extending said finger from said carriage.

15. Apparatus as in claim 6 wherein said heating means for forming the groove are mounted on said carriage.

16. Apparatus as in claim 12 wherein said heating means for forming the groove are mounted on said carriage.

17. Apparatus according to claim 7 wherein said second supporting means comprises roller means having a plurality of grooves therein to permit the heat to flow therethrough from the preheating means to the tube.

18. Apparatus as in claim 17 wherein said roller means includes a roller formed by a series of spaced sections having a slip joint connection for permitting longitudinal expansion and contraction of the roller.

19. Apparatus as in claim 7 further comprising a heat retaining hood for said preheat means carried by said carriage.

20. Apparatus as in claim 7 wherein said heating means for forming the groove are mounted on said carriage.

References Cited UNITED STATES PATENTS 3,169,657 2/1965 Olsen 65109 X 3,186,819 6/1965 Thorington et a1. 65-109 X FOREIGN PATENTS 117,427 8/ 1943 Australia.

S. LEON BASHORE, Primary Examiner.

A. D. KELLOGG, Assistant Examiner.