JPS5838254B2 - Kankakuchiyousouchi - Google Patents

Description

[Detailed description of the invention] FIELD OF THE INVENTION The present invention relates to a vessel dilator.

The tubes of heat exchangers and similar devices are fitted with fins.

Typically, the fins are fitted onto the tube and the tube is then expanded to create a tight mechanical connection between the fins and the tube.

This mechanical coupling provides an efficient means of transferring heat to and from the medium circulated within the tube while air or other gas passes over the fins.

In order to produce a very tight bond, it is desirable to extend the outside diameter of the tube to a greater extent than the inside diameter of the hole in the fin through which it passes.

The most common means of making such heat exchange devices is to bend the tube into a U-shape before inserting it into the stack of fins.

There are several specialized machines and devices used for tube expansion in finned heat exchange equipment.

Generally, the equipment used will be governed by the following factors.

(1) the size of the tube coil to be expanded; (2) the total amount of tube coil to be expanded; and (3) the amount of each tube coil size to be expanded in a single production unit.

to justify the cost of the required machinery, and its overall size;
Tube coil production equipment, whose average production unit volume and tubing coil dimensions result in a highly productive machine, employs a type of tubing expansion device that expands one or more tubing coils in a single cycle.

Such machines or mechanical tube expanders are designed to expand all the tubes of one heat exchanger in a single operating cycle.

The basic principle used is to push a number of rods with bullet-shaped or spherical ends through the tubes of the heat exchanger.

The end of the rond is sized and configured to expand the inner diameter of the tube to the desired size and create the desired interference fit between the outer diameter of the tube and the fin collar.

Some mechanical tube expanders are designed to force the expansion rond downward through the tubes of the heat exchanger, and others are designed to pull the expansion rond through the tubes.

Most often, the required power is provided by a hydraulic cylinder.

Commercially available mechanical duct dilation devices are automated, relatively complex, and expensive.

A relatively large vessel dilator is described in US Pat. No. 2,631,645.

A device for expanding very thin-walled tubes located in one passageway is also described in US Pat. No. 3,021,596.

Two portable devices for processing metal are described in US Pat. No. 1,753,677 and US Pat. No. 2,480,629.

Another way to expand the tube is to fill the tube with water, fit special pressure-resistant plugs into the openings at both ends, apply enough pressure to the water to bulge the tube, expand the tube, and fit tightly into the fins. It is meant to match.

This method inherently has several drawbacks, including the inability to control precise expansion of the tube.

Another method used to expand tubes is to force a ball or bullet shape through the tube using water, pneumatic or hydraulic pressure.

This method can cause the tube to rupture, and bullet-shaped objects can become stuck inside the tube.

SUMMARY OF THE INVENTION The present invention provides a tube dilator that is simple in construction and quick to operate.

The tube expanding device of the present invention includes a framework, a tube grasping jaw supported by the framework in front of the framework, and a rond which is supported by the framework so as to be slidable in the axial direction and coaxially passes through the tube grasping jaw. and a drive device for axially advancing and retracting the rod relative to the framework and tube gripping jaws, the tube gripping jaws having a plurality of rods arranged symmetrically with respect to the axis of the rod. The jaw member has a rear end portion attached to the framework and expands radially outward with respect to the end axis using the rear end portion as a fulcrum. Possibly, the jaw member is elastically biased radially inward with respect to the rod axis so that the forward end grips the outer circumferential surface of the rear end of the tube to be expanded; The rod has a radially inward camming surface, the rod has an enlarged headed end at its forward end, and the headed end of the rod projects forwardly from the tube gripping jaw so that the tube gripping jaw grips the tube. When the tube is in the tube, the tube is thrust into the tube to expand the tube, and when the tube is retracted into the tube gripping jaw, the jaw member is pushed against a cam surface of the jaw member to expand the jaw member against the elastic bias. The tube is thereby released from the tube gripping jaws.

The tube expansion device of the present invention expands the tube by advancing the rod, and the tube grasping jaws are automatically released by retracting the rod after the tube expansion is completed. The time required for expansion work is reduced.

Now, with particular reference to FIG. 1, a large number of heat exchange fins 21
One embodiment of a portable tube dilator 20 for dilating a tube 22 therethrough is shown.

Although the duct dilator is described herein as dilating two ducts at the same time, it will be understood that the present invention includes duct dilators for the dilation of a single duct or for the dilation of more than one duct. .

The tube expansion device 20 has a pair of hollow cylinders 24 and 25 that are fixed at both ends to a body 28 and a locking plate 31, respectively.

A pair of tie rods 26 and 27 pass through the body 28 and the lock plate 31 and are fixed at both ends to the end plate 32 and block 35, respectively.

Tube gripping jaws 23 are mounted on a block 35 and are biased toward each other by a spring device 36.

A pair of rods 37 and 38 can be slid into tube 22 from cylinders 24 and 25, respectively, to expand tube 22.

Rods 37 and 38 are moved by hydraulic pressure applied to the ends of cylinders 24 and 25.

FIG. 2 is an enlarged cross-sectional view of the left side portion of the tube dilator shown in FIG.

The expansion jaw 23 has an upper side 40 and a lower side plate 39 which are jaw members, and the base ends of the upper and lower plates are pivotally connected to the block 35 by a pin 42.

Plates 40 and 39 are each provided with a slot 41 (FIG. 5) for receiving block 35.

The plates 40 and 39 are therefore formed with ears 59 and 60 through which the pin 42 projects into the block 35.

The spring device 36 is biased to force the plates 40 and 39 together.

The spring device consists of a bolt 43 passing through plates 39 and 40, and a coil spring 44 placed over the shaft of the bolt and compressed between plate 40 and a nut fitted on the end of the bolt.

Bolt 43 is located between piston rods 37 and 38 which slide within jaws 23.

Plates 40 and 39 are spaced apart and have separate passages for receiving the axes of piston rods 37 and 38.

One of the passages 63 is shown in FIG. 2, with the piston rod 37 being received for free movement therein.

The passages 63 each open into a separate chamber 54 in which a collar is disposed.

One of the collars, 55, is shown in FIG. 2 and is slidably fitted onto the rod 37.

A similar collar is slidably fitted to the rod 38 within the chamber.

Each collar is provided with a camming surface 56 which contacts camming surfaces 64 of plates 39 and 40 when the piston rod is retracted.

To engage tube 22 with tube gripping jaws 23, piston rods 37 and 38 are retracted so that their spherically headed ends 57 contact collar 55 and cam surface 56 is brought into contact with cam surface 6.
4, thereby pivoting plates 39 and 40 on one side of pin 42 in the direction of arrows 61 and 62, respectively.

The tube gripping jaws are then opened as shown in FIG. 6, and the jaws are placed adjacent to the tube end plates 58 so that the tube 22 is held in place by the upper and lower plates 3 of the jaws.
9 and 400 into the passageway 65 (FIG. 6).

The piston rods 37 and 38 are then pushed to the left as seen in FIG. 6 to remove the pressure applied between the cam surfaces 56 and 64, and the upper and lower jaw plates 39 and 40 are moved by the pressure of the spring 44 to the arrows 61 and 64. 62 (FIG. 2) in the opposite direction.

Continued movement of piston rods 37 and 38 to the left causes headed end 57 to enter tube 22.

The outside diameter of the headed ends 57 of rods 37 and 38 is greater than the inside diameter of tube 22.

First, the fin 21 is fitted onto the tube 22, and the hole in the fin that receives the tube 22 is slightly larger than the outer diameter of the tube 22.

Thus, as the headed end 57 passes through the tube 22, the tube 22 is enlarged such that its outer diameter is greater than the original diameter of the hole in the fin receiving it.

An interference fit therefore occurs between the fins and the tube 22, providing a strong mechanical connection.

After the headed end 57 has passed through the entire length of the tube 22, the piston rod is retracted until the jaws open as shown in FIG. 6, thereby completing the process.

The surface of the passageway 65 may be suitably serrated to prevent slippage between the jaws and the tube when the jaws engage the outer periphery of the tube.

The hollow cylinders 24 and 25 are fixed to a body 28 (FIG. 1) and a locking plate 31.

The body 28 has a block 46 (FIG. 2) fixed to a plate 47, to which the cylinders 24 and 25 are connected by welds 48.

Through holes are provided in the block 46 and the plate 47 so that the tie rods 26 and 27 can freely pass therethrough.

Block 46 may also be provided with suitable bearings to provide relatively smooth movement between the tie rod and block.

Piston rods 37 and 38 are connected to block 46 and plate 47
and extend into cylinders 24 and 25, respectively.

The ends of the piston rods 37 and 38 opposite the headed ends 57 are connected to pistons that are slidable in the cylinders 24 and 25.

For example, piston rod 37 is secured to a piston 67 (FIG. 4) that is slidable within cylinder 24.

Piston 67 is provided with a circle ring 68 to prevent fluid from passing between the piston and the cylinder.

A similar piston is connected to piston rod 38.

By applying hydraulic pressure to the end face 69 of the piston connected to the rods 37 and 38, the headed end 57 is pushed to the left in the drawing.

Similarly, by applying hydraulic pressure to the end face 70 of the piston connected to the piston rods 37 and 38, the headed end 57 is pushed to the right in the drawing.

Both cylinders 24 and 25 are welded 71 to the locking plate 31.
(Fig. 4).

Tie rods 26 and 27 pass through locking plate 31 and end plate 3
2 with a nut 72.

End plate 32 may be provided with counterbore holes to receive the tapered ends of tie rods 26 and 27.

The end of the tie rod is threaded to receive a nut 72.

A pair of hollow shafts 73 and 74 (FIG. 1) are fixed to plate 32 and extend sealingly and slidably into cylinders 24 and 25, respectively.

Axis 73 will be discussed below, but it should be understood that similar explanations apply to axis 74 as well.

Shaft 73 (FIG. 4) is provided with an O-ring at tip 79 to prevent fluid from escaping from cylinder 24.

The opposite end of shaft 73 is connected to fluid nozzle 33 .

The center 76 of the shaft is hollow to allow passage of fluid between the nozzle 33 and the cylinder 24.

Shafts 73 and 74 are secured to end plate 32 and tapered at location 78 and fitted with snap rings 77 to prevent relative movement between the end plates and the shaft.

Hydraulic pressure is applied to the end faces 69 of the pistons in cylinders 24 and 25 by forcing liquid through hose 34 to nozzle 33 and further into the cylinder.

Hydraulic pressure is also applied to the end faces 70 of the pistons in cylinders 24 and 25 by forcing liquid through ports 80 (FIG. 5) in block 46.

The block is shown partially cut away in FIG. 5 with the fluid nozzle removed from the port 80 for clarity of illustration.

Port 80 opens directly into a hole receiving piston rod 38 and then through passage 81 into a hole receiving piston rod 37.

A pair of brushings 50 are sealingly attached to block 46 to prevent fluid from leaking from the block.

The piston rond passes freely through the pushing 50 but is in sealing engagement therewith.

An O-ring 83 (FIG. 2) is attached to the bushing 50 to prevent fluid from leaking between the bushing and the block 46.

Bushing 50 is enlarged adjacent cylinders 24 and 25 to form a shoulder 82 (FIG. 2) held in position adjacent plate 47 by block 46.

The inside diameter of the bushing 50 is larger than the outside diameter of the piston rod, thereby defining a fluid passageway 52 (FIG. 2).

The hollow center 51 (FIG. 2) of the cylinder 24 has a passage 5
2, communicates with a hydraulic pressure source via hole 81 and port 80.

A number of holes 83' extend radially outward from the passageway 52.
1 and allow fluid to pass through holes 81, 83' and passageway 52 into cylinder 24.

The bushing receiving the piston rond 38 is the same and has a passage and a number of holes aligned with the passage 81 and the port 80.

Thus, by applying fluid pressure through port 80, an equal force is applied to the pistons connected to rods 37 and 38.

FIG. 7 is a schematic diagram of the hydraulic circuit for operating the tube dilator.

The hydraulic cylinders 24 and 25 and the piston rod having a headed end 57 are shown in the figure.

Valve 89 has positions 86, 87 and 88 in alignment with a fluid hose connected to nozzle 33 and port 80.

When the position 86 of the valve 89 is aligned with the fluid hose, fluid pressure is applied from the pressure source 84 through the port 80 to the end face 7 of the piston.
0, thereby retracting the headed end 57.

At the same time, fluid is drained from the cylinder via nozzle 33 to drain 83.

When the valve position 87 is aligned with the fluid hose, the headed end 57 remains stationary.

When the valve position 88 is aligned with the input hose by pushing the valve to the left in FIG.
9 will be informed.

At the same time, fluid drains from the end face 70 of the piston to the drain 83.

Flow equalizer 85 applies an equal force to each piston to ensure that each headed end 57 protrudes the same amount from the cylinder.

A suitable pump is provided to force fluid into the cylinder from a fluid source 84.

The vessel dilator described above is particularly useful because it is portable.

Moreover, the stroke length of the piston rod can be easily adjusted.

Normally, relative movement between tie rods 26 and 27 and locking plate 31 is prevented.

A suitable locking screw 90 (FIG. 1) is screwed into plate 31 to force the locking device against tie rods 26 and 27.
Prevent relative movement against.

It is also possible to bring the screw 90 into direct contact with the tie rod.

By loosening screws 90 (only one shown in FIG. 1), plate 32 is moved toward plate 31, thereby removing tie rod 2.
6 and 27 to pass through the plate 31 and the body 28, and the jaw 23 is projected to the left of the body 28 (as shown in FIG. 1).

At the same time, shafts 73 and 74 extend further into cylinders 24 and 25, thereby limiting movement of the pistons connected to piston rods 37 and 38 to the right (FIG. 4).

Shafts 73 and 74 can similarly slide toward and away from the pistons within cylinders 24 and 25.

When the jaw 23 moves away from the body 28, the headed end 57
The pistons also move together with the jaws and push the pistons connected to piston rods 37 and 38 toward the body 28.

Thus, the distance between the body 28 and the end face 70 of the piston is reduced, limiting the distance that the headed end projects from the jaws.

Body 28 prevents the piston from exiting the cylinder.

The stroke of the piston rod is thus controlled by adjusting the distance between plates 31 and 32.

A pair of handles 29 and 30 (Fig. 1) are connected to the cylinder 2.
4 and 25 so that the tube dilator can be easily grasped by hand.

FIG. 8 is an end view taken along line 8-8 of the headed end 57 shown in FIG.

In many cases, the pressure of the air in the expanded tube in front of the headed end 57 increases.

This is because as the headed end 57 moves into the tube, the volume within the unexpanded portion of the tube decreases.

Accordingly, a groove 92 is formed in the side surface of the headed end 57 to allow air in front of the headed end to flow beside the headed end.

When expanding a U-shaped tube with a pair of expansion rods, only one of the headed ends 570 needs to be provided with the groove 92.

An alternative embodiment of the ventilation structure is illustrated in FIG.
In this embodiment, the expansion rod 91 connects the headed end 94 with the fastener 93.
It is attached with.

A hole 95 extends through the fastener 93 and opens into a threaded hole formed in the rod 91.

Holes 96 extend radially from the threaded holes to allow air in front of the headed end to flow through holes 95 and 96 to the rear of the headed end.

Referring now to FIG. 10, one embodiment of an apparatus for expanding tube 22 is illustrated.

Apparatus 100 is fitted with a pair of rod supports 101 and 102 which slidably receive rods 103 and 104, respectively.

A plate 105 is fixed to one end of rod supports 101 and 102 to limit movement of rods 103 and 104 in the direction of arrow 106.

A pair of adjustable stops 107 and 108 are attached to rods 103 and 104, respectively, and movable jaws 109 and 110 are attached to framework 111.
When the robot moves forward to the maximum extent, it contacts the plate 105.

FIG. 11 is a sectional view taken along line 11-11 in FIG. 10.

Rods 104 and 103 are slidably attached to framework 111 and their headed ends are normally located within jaws 110 and 109 but can project forwardly therefrom to enlarge tube 22.

Apparatus is provided in the framework 111 for actuating the rods 103 and 104 to cause the headed ends thereof to protrude from the jaws for expansion of the tube 22.

The device includes a hydraulic motor 112 secured to an end plate 113 of a framework 111.

The rotatable drive shaft 114 of the hydraulic motor 112 is connected to the end plate 1
It passes through a roller bearing 114' provided in 13.

A gear 115' is fixed to the shaft 114 and meshes with a gear 115 fixed to the shaft 1116.

The shaft 116 is rotatably fitted in bearings 117 and 118 provided on plates 113 and 119, respectively.

In this manner, by operating the hydraulic motor 112, the drive shaft 114 is rotated, thereby causing the shaft 116 to rotate.
is rotated via gears 115' and 115.

Plate 1 such that cover 120 surrounds gears 115' and 115.
It is attached to 13.

The shaft 116 has a pair of hexagonal sections 121 and 122, which are connected to clutches 123 and 12, respectively.
It is received in a hexagonal hole provided in 4.

Rod drive gears 125 and 126 are pinned to clutch butts 128 and 129, respectively, through which shaft 116 passes.

A spring force is applied to the clutch by a washer-shaped spring 130 between the plate 119 and a hexagonal nut 131 screwed onto the shaft 116.

In this manner, rotation of shaft 1160 causes rotation of rod drive gears 125 and 126.

A floating shaft 132 is attached to plates 113 and 119 above shaft 116.

The second pair of rod drive gears 133 and 134 are bearings 13
5 is rotatably attached to the floating shaft 132.

The teeth of gear 133 mesh with the teeth of gear 125, while the teeth of gear 134 mesh with the teeth of gear 126.

Each gear is provided with a continuous groove on its outer circumferential surface.

A portion of the outer peripheral surface of gears 125 and 133 extends between gears 125 and 126 and rod 104 is received in groove 137.
are tangentially aligned and in contact.

Similarly, a portion of the outer peripheral surface of gears 126 and 134 is
Rod 103 extending between 36 and 134 and received in groove 138 is in tangential alignment and contact.

When the rod 1 drive gear is rotated, grooves 137 and 13
The surfaces forming the rods 8 are in contact with the outer peripheries of the rods 104 and 103, thereby propelling them through the framework 111.

Gears 133 and 134 are spacers through which the shaft 132 passes.
139.

Both ends of floating shaft 132 are received in slots provided in plates 119 and 113.

For example, plate 119 (FIG. 10) is provided with a slot 140 through which shaft 132 passes.

Adjusting screws 141 and 142 projecting into the floating shaft 132
Pressure is applied to rods 103 and 104 via gears 133 and 134 (FIG. 11).

Springs 143 and 144 are arranged between floating shaft 132 and the enlarged heads of adjusting screws 141 and 142, respectively.

Thus, by tightening the adjustment screw, springs 143 and 144 apply a downward force to the idler shaft, thereby forcing the rod drive gear more firmly against the rods 103 and 104.

Plates 113 and 119 are connected to side wall 143 (FIGS. 9 and 14).
It is fixed at 4.

Hollow rod supports 101 and 102 are mounted on wall 144K and aligned in the mutually facing grooves of gears 125 and 133 and gears 126 and 134.

Similarly, jaws 109 and 110 are mounted to wall 143 and aligned with rod supports 101 and 102.

Thus, the rods 103 and 104 are connected to the rod supports 101, 1
02 between rod 1 drive gear and jaws 109 and 11
Penetrates 0.

FIG. 12 is a sectional view of jaw 110, which is equivalent to pawl 109.

A headed end 145 of rod 104 is shown projecting outwardly from jaw 110.

The jaw 110 has a cylindrical shape and has four jaw members 146 and 147, which are made by dividing the cylinder vertically into equal parts.The rear end (the right end in FIG. 12) of each jaw member is attached to the wall 143 by an end plate 148. The attached five jaws 110 have converging surfaces 149 and 150 which are conical camming surfaces which contact the headed end 145 when the rod is pulled in the direction of arrow 152, and the tube 22 ( Fig. 10) to engage the jaws.
The rod is retracted until its headed end contacts the converging surface in each jaw, thereby causing the jaws to expand into a generally conical shape.
2 is inserted into the jaw.

Rods 103 and 104 are then moved in the opposite direction of arrow 1520 so that the jaws can grip tube 22 firmly.

Referring now to FIGS. 13-15, an alternative embodiment of an apparatus for dilating a tube is illustrated.

Apparatus 200 is similar to the apparatus shown in FIGS. 10 and 11, except that more rond drive gears are used to move the rond through the framework and jaws.

Moreover, the hydraulic motor is connected to the rod 1 drive gear shaft 116 of the device 100 by coupling gears to each other, and in this embodiment, the hydraulic motor is coupled to the rod 1 drive gear shaft by coupling the gears to the chain. has been done.

Device 200 has a pair of hollow rod supports 201.

Hydraulic motor 202 is attached to end plate 204 by bolts 203.

The rotatable output shaft 205 of the hydraulic motor 202 is connected to the plate 20
It passes through a bearing 206 provided at 4.

The gear 207 meshes with a roller chain 208 fixed and connected to the tip of the shaft 205, and the chain is connected to the rod 210.
It meshes with a gear 209 fixed to.

Clutch drive plates 211 and 212 are fixed to the rod 210.

A pair of drive gears 213 and 214 are mounted on shaft 210 and keyed to clutch plates 215 and 216 through which the shaft passes.

Clutch pads 217 and 218 are held between clutch drive plates 211 and 215 and clutch drive plates 212 and 216, respectively.

Pressure is applied to the clutch by a spring 219.

The spring is pressed against the gear 209 by a nut 220 fitted on the rod 210.

Rod 210 is rotatably received by bearings 221 disposed between gears 213, 214 and the rod.

Similarly, gears 213 and 214 are rotatably mounted by bearings 222 located in plates 223 and 224.

The slipping clutch prevents damage to the tube and device 200 being expanded.

When rods 225 and 226 are extended the maximum distance, the clutch will slip until the operator reverses motor 202.

Shafts 230 and 231 are attached to plates 224 and 223.

Rod drive gears 232 and 233 are rotatably attached to the shaft 230.

Similarly, shaft 231 has rod drive gears 234 and 235.
is rotatably mounted.

Rod drive gears 232 and 234 mesh with gear 214, while rod drive gears 233 and 235 mesh with gear 214.
It meshes with 3.

Therefore, when the rod 210 rotates, the gears 213 and 214
and the rod drive gears 232 to 235 rotate.

Idle shafts 236 and 237 are attached to end plates 223 and 224, and each idler shaft has a pair of rod drive gears that mesh with rod drive gears attached to rods 230 and 231.

For example, the idler shaft 236 is connected to the rod drive gears 232 and 23.
A pair of Rondo drive gears meshing with 3 are attached.

Similarly, the idle shaft 237 is connected to the rod drive gears 234 and 235.
A pair of Rondo 1 drive gears are attached that mesh with each other.

The rod 226 is a rod, the drive gear 232 and the idler shaft 236
and between the corresponding rod drive gear mounted on the rod 1 drive gear 234 and the corresponding rod drive gear mounted on the idler shaft 237.

Similarly, the rod 225 is connected to the rod drive gear 233 and the idler shaft 2.
36 and between the rod drive gear 235 and the corresponding rod 1 drive gear mounted on the idler shaft 237.

Thus, actuation of the hydraulic motor positively drives the rod drive gears 232-235 thereby driving the rod 225 through the rod support 201, framework and jaws 250.
and move 226.

The various embodiments of the apparatus of the invention shown in FIGS. 1, 10 and 13 may use jaws of the type shown in FIGS. 2 or 12.

Jaw 250 is similar to the jaw shown in FIG.
5, jaw 250 differs in that it does not have collar 55 and the headed ends of rods 225 and 226 directly contact the cam surface of the jaw member.

Additionally, a pair of tubes 251 and 252 are mounted within the jaws and are adapted to pass through rods 225 and 226, respectively, thereby limiting inward movement of the headed ends of the rods.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of one embodiment of a tube expansion device shown coupled to a heat exchange device. FIG. 2 is an enlarged partial cross-sectional view at 22 of FIG. FIG. 3 is a partially enlarged sectional view taken along line 3-3 in FIG. FIG. 4 is an enlarged partial sectional view taken along line 4-4 in FIG. FIG. 5 is a partial sectional view of the left end of the tube expansion device of FIG. 1; FIG. 6 is a partial view of the left portion of the tube dilator of FIG. 2 showing the jaws in the open position; FIG. 7 is a schematic diagram of a hydraulic circuit for operating the tube expansion device of FIG. 1; FIG. 8 is an end view of the headed end 57 viewed from 8-8 in FIG. FIG. 9 is a side view of one embodiment of the expansion rod. FIG. 10 is a perspective view of another embodiment of the tube expansion device. FIG. 11 is an enlarged sectional view taken along line 11-11 in FIG. 10. FIG. 12 is an enlarged sectional view taken along line 12-12 of FIG. 10, showing the rod protruding forward from the jaw. FIG. 13 is a side view of a tube dilator similar to the tube dilator shown in FIGS. 10 and 11, but with two sets of drive wheels instead of a J set. FIG. 14 is an enlarged sectional view taken along line 14-14 in FIG. 13. FIG. 15 is a partial top view of the expansion device of FIG. 13; 20,100,200...canal expansion device, 22.
...Tube, 23,109,110,250...
...Pipe gripping jaw, 28,111...Framework, 3
7,38;1 03,104;225,226
...Rod, 39, 40; 146, 147...
...Shoichi material, 57,94,145...
Headed end, 64; 149, 150...Cam surface.

Claims (1)

[Claims] 1 a framework, a tube gripping jaw supported by the framework in front of the framework, a rond supported by the framework so as to be slidable in the axial direction and extending coaxially through the tube gripping jaw; It consists of a framework and a drive device for advancing and retracting in the axial direction relative to the tube gripping jaw,
The tube gripping jaw has a plurality of jaw members arranged symmetrically about the axis of the rod, the jaw members including:
A rear end portion is attached to the framework, and is capable of expanding radially outward with respect to the rod axis using the rear end portion as a fulcrum, but is elastically biased radially inward with respect to the rod axis, so that the front end portion grips the outer peripheral surface of the rear end of the tube to be expanded, the jaw member has a cam surface radially inward with respect to the rond axis, and the rond has an enlarged headed end at the front end. The headed end of the rod protrudes forward from the tube gripping jaw, and when the tube gripping jaw grips the tube, plunges into the tube to expand the tube and retreats into the tube gripping jaw. When the tube is released from the tube gripping jaws, the tube is released from the tube gripping jaws by pushing the cam surface of the jaw member and expanding the jaw member against the elastic bias.