US2767462A - Method of retractively expanding tubes into tube seats - Google Patents

Description

H- C. MATHEWS Oct. 23, 1956 METHOD OF RETRACTIVELY EXPANDING TUBES INTO TUBE. SEATS Filed Jan. 27, 1954 3 Sheets-Sheet l INVENTOR. HAROLD c. MATHEWS BY W;%

ATTORNEYS Ocf. 23, 1956 c. MATHEWS 2,767,462

METHOD OF RETRACTIVELY EXPANDING TUBES INTO TUBE SEATS Filed Jan. 2'7, 1954 5 SheetsSheet 2 ID ID I I n h 1 no I a I /l I I (D 2 I 3 K) II N I T 1 ,2

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HAROLD C. MATHEWS BY W W ATTORNEYS H, C. MATHEWS Oct. 23, 1956 METHOD OF RETRACTIVELY EXPANDING TUBES INTO TUBE SEATS Filed Jan. 27, 1954 5 Sheets-Sheet 3 FIG-3 IN VEN TOR. HAROLD C. MATHEWS ATTORNEYS United States Patent METHOD OF RETRACTIV ELY EXPANDING TUBES INTO TUBE SEATS Harold C. Mathews, Springfield, Ohio, assignor to The Airetool Manufacturing Company, Springfield, Ohio, a corporation of Ohio Appiication January 27, 1954, Serial No. 406,486 2 Claims. (Cl. 29-1575) This invention relates to a method for the expansion of tubes in tube seats by means of roller expanders, and is particularly concerned with a method which both controls the degree of expansion of the tube against the seat and provides for facile removal of the expander and associated equipment from a seat.

This application is related to my co-pending applications, Serial No. 184,743, filed September 14, 1950, now Patent No. 2,736,950, and Serial No. 365,629, filed July 2, 1953.

This invention particularly contemplates the provision of a method of retractively expanding tubes into tube seats; in the method a self-feeding tube expander appaillustrating apparatus utilized in the practice of the ratus is positioned within a tube and rotated to expand an interior portion of the tube against a tube seat until the expansion is complete and the apparatus stopped. Thereafter the components of the apparatus are latched together for rotational and rectilineal movement as a i tion of the tube expansion;

unit, the direction of rotation of the apparatus is reversed and the apparatus is fed from the seat while the outer portion of the tube is expanded against the seat.

This and other allied objects of the invention are attained by providing an electric power device which is adapted to drive a roller tube expander in opposite directions of rotation; this device has associated therewith means for limiting or measuring the electric current supply to the device to accurately limit the torque developed. Limiting the torque limits the expansion of the tube and the torque required will be dependent upon tube diam eter, tube Wall thickness, the material of thetube and the characteristics of the power device.

The degree of expansion for a particular tube under specific conditions is predeterminable and in the apparatus of invention the device is so set that when the proper current and hence proper torque are attained by engagement of a tube with a tube seat, apparatus responsive to the increase in current demand due to the increased torque occasions de-energization of the power device and thereafter reversal of the apparatus rotation. The stopping of the power device is'substanti'ally instantaneous since the same is under'load and the equipment is preferably arranged to provide a time delay interval between the stopping and the starting of rotation in the opposite direction. This time delay in retractive expansion methods permits a manual manipulation of the tube expander as will appear more particularly hereinafter. 7 i

In the reverse direction of rotation the control apparatus which effects the stopping is out of theelectric circuit and the power device is substantially across the voltage supply line.

The apparatus is fully controllable in either the reverse or forward direction as in addition to a starting switch an auxiliary switch is provided which is actuable to move the expander in the reverse direction only. This latter control is etfective to permit removal of the apparatus from a tube seat should jamming occur in the course of the tube expansion. Thus should the motor stall when either rotating in the forward of reverse direction it is not necessary to rotate the expander apparatus in a forward direction prior to rotation in a reverse direction to effect the apparatus removal from the tube seat.

Referring to the retractive method of tube expansion set out in my co-pending applications hereinbefore mentioned, the expansion is effected by placing the expander in the tube to expanded, the expander being positioned to the inner side of the tube seat, effecting the expansion to the desired degree, latching the mandrel of the expander which urges the roller expanders against the tube seat against axial movement, and then rotating the apparatus in the reverse direction to simultaneously effect expansion and apparatus withdrawal from the tube seat.

With the apparatus of this present invention the re versal is effected automatically, but should the power device stop in the course of the initial expansion, or when the equipment is rotating in the reverse direction, the mandrel may be axially unlatched and the power device operated with the manual switch to thus release the expander rolls and to permit the equipment to be completely removed from the tube seat.

The invention will be more particularly described by reference to the following detailed description and accompanying drawings wherein:

Figure 1a is an elevational view, partially in section,

method of invention, the tube expander apparatus being shown as positioned within a tube in a tube seat, with the apparatus unlatched for relative axial movement of the components and ready for the first step in the opera- Figure l!) is a view similar to that of Figure 1a, with parts broken away, and illustrating a succeeding step in the expansion operation wherein the tube has been expanded against an interior portion of the tube seat, the apparatus being in the unlatched position as in Figure la, but the motor and mandrel having been advanced rightwardly;

Figure 1c is a view similar to the prior views with parts broken away and illustrating a step in the expansion operation wherein the components including the motor and mandrel have been latched against axial movement rela tive to other components of the apparatus and the tube has been expanded against an outer portion of the tube seat in the course of withdrawal of the apparatus from the seat;

Figure 2 illustrates the arrangement of the power device, relays and control circuits for the operation of the equipment illustrated in Figures 1a, 1b and 1c;

Figure 3 illustrates a preferred arrangement of a portion of the circuit of Figure 2;

Figure 4 is a sectional view taken on line 4-4 of Figure la with the apparatus in an unlatched position;

Figure 5 is a somewhat enlarged sectional view taken substantially on line 5-5 of Figure 4;

Figure 6 is a cross-sectional view similar to that of Figure 4- but with the apparatus in a latched position;

Figure 7 is a somewhat enlarged sectional view taken substantially on line 77 of Figure 6.

Referring first to Figure la wherein apparatus particularly adapted for the automatic retractive expansion of a tube is illustrated, there is shown at 1 a tube sheet wall portion having a seat 3 in which a tube 5 is loosely positioned, and for convenience it may be assumed that the other end of tube 5 (not shown) has already been secured in an opposed tube sheet wall.

Shown within the tube 5 at the inner end of the seat is a roller tube expander having a cage 7 carrying radially movable rollers 9 which are urged radially outward to effect expansion by the passage of a self-fed tapered mandrel 11 through the rollers rightwardly as shown in Figure 1a. A fixed stop member 13 on cage 7 limits the traverse of the cage into the tube sheet in the operation of the device by abutting against the outer wall of the sheet, The mandrel 11 is square-headed and fixedly secured by a pin 18 or in any other suitable manner to shaft 15 of portable electric motor 17 for rotational and rectilineal movement with the shaft when the motor is moved while it is operating. Surrounding the mandrel 11 leftwardly in Figure la is a cylindrical rack sleeve 19 (Figure 4) fixedly secured to the nose of motor 17 and carrying spaced racks 20 cut into the surface thereof preferably at 9t) degrees intervals. The inner end of sleeve 19 is indicated at 26. Mounted for sliding move ment on sleeve 19 is a latching sleeve 21 having spring biased latching blocks 23 (also at 9-3 degrees intervals) provided with teeth 24 and which are adapted upon rela tive rotation of sleeve 19 and 21 to mesh with the racks 29 to inhibit relative longitudinal sliding movement of the sleeves. The spring for biasing the blocks is indicated at 22. The amount of turning necessary to latch or free the sleeves is most suitably /ath of a revolution of the latching sleeve. Latching sleeve 21 carries cage 7 which is freely mounted for rotation with respect to the sleeve by a nut and bearing indicated generally at 25 and fully described in my co-pending application, Serial No. 365,629, referred to hereinbefore. Thus the cage is exteriorly threaded at 8 and the cage is received in the nut it} which is itself in threaded engagement at 12 with the outer or latching sleeve 21; the nut retains the ball bearing 14 and the bearing provides for rotatable support of an internally threaded collar or cage-retaining means 16 in which the cage is shown (Figure In) as threadedly secured at 23. The cage is thus held that it may revolve freely while it is axially fixed with respect to the cage-retaining means. Accordingly by meshing engagement of the latching and rack sleeves the cage may be restrained against axial movement while being freely rotated.

in Figure 1a the latching blocks are shown as out of meshing engagement and the sleeves 19 and 21 are rela tively slidable and the mandrel may self feed; this unlatched condition of the sleeves is more clearly shown in Figures 4 and 5. In Figures 6 and 7 the latching sleeve is shown as rotated about Asth turn to cause engagement of the racks 2i? with the teeth 24 of the latching blocks.

Control apparatus indicated generally at 29 supplies power to the motor 17 and will itself be more specifically described in connection with Figure 2. However it should be noted at this time that tube expansion is effected by positioning the apparatus as shown in Figure in; this position is attained by the operator grasping the motor, which is similar to a portable electric drill, in one hand and the latching sleeve in the other. The operator urges the motor and mandrel forward, the tapered mandrel passing through cage 7 to engage the rollers; the cage is passed into the tube seat until the preset stop member 13 threaded on the cage limits the movement of the cage to the correct position the mandrel in engagement with the rollers biasing the same outwardly. Then the motor is set into operation and the mandrel self feeds and the rolls move radially outwardly against the tube seat the mandrel itself moving rightwardly in Figure 1a; when the expansion reaches the predetermined amount as indicated in Figure lb the control apparatus 29 occasions first the stopping of the motor and then the reversal of the motor. The motor in the grasp of the operator, and the sleeve 19, during the expansion, move with the mandrel since the motor is secured to the mandrel and the sleeve is secured to the motor, as already noted.

The attainment of the proper degree of expansion is indicated to the operator by the flashing of dial light 31 on control apparatus 29, and he quickly moves the latching sleeve Aith of a turn to latch the two sleeves together to prevent relative axial or longitudinal movement between the sleeves and hence also between the cage and the mandrel also. The apparatus then automatically reverses its direction of rotation within the tube 5 and the self-feeding of the mandrel and rolls urge the same outwardly as a unit, expanding the tube and rolling the metal outwardly as shown in Figure Is as the equipment is automatically withdrawn from the tube seat. This outward movement of metal is initiated as indicated in Figure 112 when the tube is first subjected to expansion and continues, as shown in Figure 1c, through the completion' of the expansion and withdrawal of the apparatus from the tube seat.

As shown in the drawings motor 17 is provided with a switch 33 and a manually operable reversing switch 35. The control unit 29 is provided with dial light 31, socket 37 for receiving the plug of the motor, a power line socket 39, a low-high range toggle switch 42 for selecting the scale of ammeter 41, an onoff switch 45, and a movable control 47 on the control unit limits the current fiow to motor 17.

Referring particularly to Figure 2 where the components of the circuit are shown in their inoperative position, similar numerals being used to designate the parts shown in Figure 1, motor 17 is connected by leads 49, 51 to manual reversing switch 35, and the latter is connected by lead 52 to one side of switch 33; switch 35 is also connected to a motor reversing relay 53 through ammeter 41 by lead 55; the relay 53 has a normally open and a normally closed position and is connected to the ends of field coil 56 of the motor 17 and to contacts of relays 68 and 71. Reversing relay coil 57 controls the actuation of relay 53.

A cut-01f relay 58 which also has a normally open and a normally closed position makes electrical contact in the normally closed position with reversing relay 53 through lead 59; relay 58 is also connected through lead 60 to on-otf switch 45 and to one end of auto-transformer 61 which latter is also directly connected to switch 45 through lead 62. Relay 58 is actuated by current flow in the coil indicated at 63.

Current transformer 61 has in parallel therewith resistor 64 and high-low switch 42; resistor 65 which is directly connected to the movable arm 47 of rheostat 66 which latter has in series therewith fixed resistor 67. These resistors 64, 65 and 67 are precision resistors and control the scale values of ammeter 41.

Also in parallel with the auto-transformer 61 is the normally open control circuit time relay 68 which governs the application of current to coil of single acting current relay 71. The relay 68 is controlled by current flow through coil 69 and the relay 68 serves to delay the application of current to coil 70 until motor 17 is up to speed and thus prevents the current relay 71 from kicking out during starting of the motor. The relay 71 which is normally open has connected thereto one side of double acting reversing time relay 72 which relay is actuated by current flow through coil 74 and is effective when operated to place the reversing relay coil 57 in circuit to actuate the reversing relay 53. The closure of relay 71 which occurs in response to the predetermined increase of torque occurring when tube 5 has been sufiiciently expanded into engagement with the seat 3, also places dial lamp 31 in circuit.

Voltmeter 76 is placed across the line between leads 6!) and 77 to indicate the line voltage applied to the device.

The button switch 33 it is to be noted when closed is mechanically held in the closed position until again actuated to shut off the series motor 17. However reversing coil 57 is not connected through switch 33 but to the line on one side; accordingly upon completion of the expansion operation quick repetitive pressing of button switch 33 will not permit of throwing the motor into forward running condition as the coil 57 must be deener'gize'd to permit the reversing relay 53 to return to its normally closed position. This is a safety feature which guards against error on the part of the operator.

There is shown in Figure 3 a preferred circuit for the current flow in the coil 70 of Figure 2. The supply current normally employed is A. C. and the sensitivity of the coil 70 and the relay 71 may be materially improved if the current coil is supplied with D. C., this avoids chattering of the relay contacts and permits very close control, the equipment being operable on a current diiference of 0.01 ampere flow in coil 70.

Referring then to Figures 2 and 3 the letters a and b indicate contact points on opposite sides of the current coil and as shown in Figure 3 the coil is divided into two portions 70' and 70". Germanium diodes are indicated at 81 and 83 and are so arranged with respect to the coil that the current flow of the current coil is rectified and always in the same direction as indicated by the arrows over the coil portions 70' and 70".

Thus when contact a is for example positive the current fiow is to the positive end of coil 70", through rectifier 83 to contact b, the flow through rectifier 81 being blocked; when contact b is positive for example, the current flow through 83 is blocked, the current coursing through rectifier 81 and the positive end of coil 70' to contact a.

In the operation of the device of Figure 1a the setting of the switch 42 and the knob of the rheostat arm 47 is first determined for the particular operation, including the voltage supply, the tube diameter, tube material, and wall thickness of the tube. With switch 45 on, and toggle switch 42 positioned for the proper ammeter scale, and power supplied to the device positioned as shown in Figure 1a switch 33 (Figure 2) is closed to the lower side and the motor 17 is thereby rotated in the forward direction; all other components are at this time in their normal position shown in Figure 1a.

With the closure of switch 33 to the lower side current flows through lead 52, the upper side of switch 35, the armature of the motor, the lower side of switch 35 through the ammeter, the upper contacts of relay 53, the field coils 56, the lower normally closed contacts of relay 53, lead 59, relay 58, the auto-transformer 61, to lead 60 and through switch 45 to the other side of the line. Thus the motor is rotated in a forward direction.

As the motor comes up to speed the control circuit time relay coil 69 becomes sufficiently energized to actuate the relay 68 and close the contacts thereof which places the coil 70 in circuit. The current carrying coil 70 is in parallel with the auto-transformer 61 which carries the major portion of the current, usually at least two or three times as much current as the relay coil 70. When the expander firmly engages the tube against the tube seat as shown in Figure lb the total current drawn by the motor increases and the current through coil 70 becomes sufliciently high to actuate the relay 71. The exact amount of current necessary to actuate the relay 71 has been determined by the setting of rheostat arm 47 as well as the positioning of switch 42 which may or may not be in circuit and with which the coil 70 is in parallel.

Closure of the normally open relay 71 immediately illuminates the dial lamp 31 indicating to the operator that the initial portion of the expansion has been completed. At the same time coil 63 is energized to open relay 58 and shut off the motor. The operator then quickly moves the latching sleeve 21 to engage the latching blocks thereof with the racks of sleeve 19, thus latching the assembly together axially.

Closure of relay 71 also places coil 74 of reversing time relay 72 in circuit, thus closing the relay and the upper contacts thereof to place the coil 57 of reversing relay 53 in circuit; accordingly relay 53 is actuated and the motor circuit is then completed to operate the motor in the reverse direction in the following manner.

Current flows through the lower side of switch 33, the upper side of switch 35 through the armature of motor 17, the lower side of switch 35, as shown in Figure 2, through the ammeter and lead 54, .the field coil 56 in a rightward direction, the upper side of relay 53, which is now in the opposite position to that shown in Figure 2, through the relay 71 and lead 60 and switch 45 to the line.

The reversal of the motor is thus automatic and the head of the cage 7 feeds leftwardly in Figure 10 out of the tube expanding the same as it moves and carrying with it extruded metal. When the cage 7 is completely withdrawn from the tube the operator shuts off the motor by again pressing the switch 33, and the unit is then ready for the next tube expansion operation.

Should failure occur while the apparatus is within the tube seat the motor 17 may be operated in the reverse direction only by throwing switch 35 to such a position that the lower contacts as shown in Figure 2 are in circuit and current will then fiow through the upper side of switch 33, the lower side of switch 35 leftwardly through the armature of the motor 17, the upper side of switch 35 (which is now engaged with the lower contact) through the ammeter 41, the relay 53 leftwardly through the coil 56 (Figure 2) through the lower normally closed contacts of relay 53 through relay 58 and auto-transformer 61, lead 60 and switch 45 to the other side of the line.

In connection with the foregoing description it is to be noted that the control unit 29 is divided into two distinct housing portions, one of which indicated at 30 in Figure 1a houses the relays 53, 58, 68 and 72. This unit plugs into the forward portion of the control unit and accordingly may be readily removed therefrom for servicing, for reshipping to the factory, etc. Accordingly should the relays, upon failure while the apparatus is within the tube seat, be in such a position that they would not permit the motor 17 to run in the reverse direction, the relay unit 36 may be opened up and the relays individually set to the proper position to permit actuation of the motor in the reverse direction as described in the preceding paragraph.

It is to be noted that should jamming occur in such manner that it is necessary to discontinue expansion that the sleeves 19 and 21 should be in their unlatched position and the mandrel 11 will then permit disengagement of the rollers with the tube wall upon reverse rotation of the equipment and the removal of the apparatus from the tube seat may be readily effected.

It is also to be noted that the unit 30 houses the time relay controls associated with relays 68 and 72 and simple adjusting screws (not shown) on the ends of the relay permit selection of the time delay. Ordinarily the control circuit time relay 68 will be adjusted to close as soon as the motor reaches full speed. The reversing time relay 72 will normally be set to provide a time delay of one to two seconds before reversal of the motor after the motor has stopped.

The current relay 71 is of the plug-in type and is housed with the rheostat and resistors in the main cabinet of the control apparatus 29.

There has thus been described apparatus for effecting tube expansion which simplifies the whole operation and which may be effected with relatively simple equipment having few moving parts. Thus the only moving parts in the control arrangement are the relays, and electronic tube apparatus is avoided completely. The motors themselves are commercially available in a number of sizes and at various speeds and are of heavy duty high torque constructions but light in weight.

The structure of invention is useful for boiler work wherein frequently the expansion is effected with a plurality of mandrels increasing in size; the utility in this respect is occasioned by the capability of the apparatus to be manually operated with switch 35 or automatically operated as described. Further the apparatus is particularly useful with angle drives due to the automatic reversal feature,

' It will be understood that this invention is susceptible to modification in order to adopt it to difierent usages and conditions and accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

I claim: 7

1. A method of retractively expanding tubes in tube seats which comprises positioning self-feeding tube expander apparatus within a tube seat to initially expand an interior portion of a tube against a tube seat, expanding the apparatus to securely engage the tube against the interior portion of the seat until the torque developed stops the rotation of the apparatus, latching the components of the apparatus together for rotational and rectilineal movement as a unit, and automatically reversing the direction of rotation of the apparatus while the same is in the latched expanded condition to retractively feed the apparatus from the seat while expanding the outer portion of the tube against the seat.

2. A method of retractively expanding tubes in tube seats which comprises positioning self-feeding tube expander apparatus within a tube seat to initially expand an interior portion of a tube against a tube seat, expanding the apparatus to securely engage the tube against the interior portion of the seat until the torque developed stops the rotation of the apparatus, maintaining the apparatus in a stopped, expanded condition for a time period after the stopping, during the time period latchs ing the components of the apparatus together for rotational and rectilineal movement as a unit, and automatically reversing the direction of rotation of the apparatus while the same is in the latched expanded condition to retractively feed the apparatus from the seat while expanding the outer portion of the tube against the seat.

References Cited in the file of this patent UNITED STATES PATENTS 1,063,179 Burnham June 3, 1913 1,456,100 Eaton May 22, 1923 1,683,221 Weber Sept. 4, 1928 1,980,395 Fitzgerald Nov. 13, 1934 2,139,117 Gohorel Dec. 6, 1938 2,203,907 Hines June 11, 1940 2,216,595 McCarty Oct. 1, 1940 2,355,852 Fisher Q. Aug. 15, 1944 2,372,605 Ross Mar. 27, 1945 2,393,283 Boyles Jan. 22, 1946 2,409,219 Maxwell Oct. 15, 1946 2,431,316 Dudley Nov. 25, 1947 2,496,574 Boger Feb. 7, 1950 2,535,782 Carlson Dec. 26, 1950 2,539,123 Dudley Jan. 23, 1951 2,546,756 Knowlton Mar. 27, 1951 FOREIGN PATENTS 19,788 Great Britain Oct 4, 1901

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