US3848485A

US3848485A - Valving machine

Info

Publication number: US3848485A
Application number: US00407416A
Authority: US
Inventors: C Grenci
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-10-18
Filing date: 1973-10-18
Publication date: 1974-11-19
Anticipated expiration: 1991-11-19

Abstract

A machine for inserting or removing a valve into or from a cylinder including means for securely holding the cylinder to prevent rotation thereof and a pair of self-adjusting, power actuated, valve tongs pivotable about a pair of parallel, spaced axes to permit one ends thereof to come into contact with opposite sides of the valve. Drive means is operative to rotate the tongs about an axis aligned with the axis of the valve to rotate the valve relative to the cylinder. The same drive means, through a power multiplying, planetary gear arrangement urges the one ends of the tongs into contact with the opposite sides of the valve with a greater torque than that used to rotate the valve whereby the tongs tightly hold the valve during turning thereof relative to the cylinder.

Description

United States Patent 1191 Grenci Nov. 19, 1974 VALVING MACHINE [76] Inventor: Carl A. Grenci, 4791 Lesa Pl.,

Yorba Linda, Calif. 92686 Filed: Oct. 18, 1973 Appl. No.: 407,416

[56] References Cited UNITED STATES PATENTS 12/1917 Carvacho 81/3.2

10/1940 Carter 29/240 UX 2/1954 Cormany 81/57.]8 X

Primary Examiner-James L. Jones, Jr. Attorney, Agent, or Firm-Philip M. Hinderstein [5 7] ABSTRACT A machine for inserting or removing a valve into or from a cylinder including means for securely holding the cylinder to prevent rotation thereof and a pair of self-adjusting, power actuated, valve tongs pivotable about a pair of parallel, spaced axes to permit one ends thereof to come into contact with opposite sides of the valve. Drive means is operative to rotate the tongs about an axis aligned with the axis of the valve to rotate the valve relative to the cylinder. The same drive means, through a power multiplying, planetary gear arrangement urges the one ends of the tongs into contact with the opposite sides of the valve with a greater torque than that used to rotate the valve whereby the tongs tightly hold the valve during turning thereof relative to the cylinder.

8 Claims, 4 Drawing Figures VALVING MACHINE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valving machine and, more particularly, to a valving machine including self-adjusting, power actuated, valve tongs that provide a positive, non-slip hold on a valve no matter how tight it is.

2. Description of the Prior Art Many machines are presently on the market for inserting or removing valves into or from pressure cylinders. Such machines are required to initially insert the valves into the cylinders with the required torque to insure a fluid-tight seal. Such machines are also required thereafter to remove the valves for normal maintenance thereof and periodic hydrostatic testing of the cylinders.

The cylinder has an internally threaded opening at the upper end thereof which receives the externally threaded stem of the valve. The body of the valve includes flats on opposite sides thereof which may be engaged for rotating the valve relative to the cylinder.

Prior art valving machines are of two general types, the crow-foot type and the mechanically adjusted clamp-tong type. The crow-foot type is characterized by a generally C-shaped member having a slot in the lower end thereof defining a pair of spaced arms for receiving the valve. Since the spacing between the arms is fixed, spacers are required for different sizes of valves.

Such valving machines have a number of disadvantages associated therewith. In the first instance, since the spacing between the arms is fixed, a certain amount of slack is required to fit the valve between the arms. However, this amount of slack can cause the arms to slip and damage the valve if the valve is exceptionally tight. Also, valves vary considerably in size from manufacturer to manufacturer as well as from new as compared to previously used valves and it is difficult to provide a firm hold.

Another problem results from the recent trend in the industry of valve manufacturing. The valves are ordinarily made from brass, but because of the expense of metals, lighter and lighter sections are being used. When using a wrench, as a crow-foot type valving machine essentially is, if the wrench slips, it can easily deform or damage the outlet connection or the safety device. Furthermore, as the wrench starts to turn, the valve material slightly deforms and no provision is made for taking up this slack.

The mechanically adjusted clamp-tong type valving machine was developed to at least partially solve these problems. This type of valving machine is characterized by a pair of tongs which are pivotable about a pair of parallel, spaced axes adjacent one ends of the tongs to permit the other ends of the tongs to be brought into contact with opposite sides of the valve body. Once the cylinder, valve, and tongs are positioned, the tongs are mechanically and manually tightened and locked to the valve body.

While this type of valving machine represents an improvement over the crow-foot type of machine, many of the problems still remain. More specifically, once the machine starts to operate and the tongs cause deformation of the valve body, there is no provision for taking up the slack created by such deformation. Furthermore, the forces on the tongs cause wear and distortion that precludes a positive grip. Thus, there is still the possibility that the tongs will slip thereby deforming or damaging the outlet connection or the safety device made integral with the valve.

SUMMARY OF THE INVENTION According to the present invention, there is provided a valving machine which solves the problems encountered heretofore. The present valving machine includes a pair of tongs pivotable about a pair of parallel, spaced axes so that one ends of the tongs may be brought into contact with opposite sides of the valve. With the present valving machine, the valve tongs are power actuated and self-adjusting so that a force urges the one ends of the tongs into contact with the opposite sides of the valve at all times during rotation of the tongs. Furthermore, the torque tending to urge the valve tongs into contact with the valve is greater than the torque rotating the tongs to insure that the tongs tightly hold the valve during turning thereof relative to the cylinder thereby preventing slipping thereof and potential damage to the valve.

Briefly, the present machine for inserting or removing a valve into or from a cylinder comprises means for securely holding the cylinder, a pair of tongs pivotable about a pair of parallel spaced axes, drive means, means operatively coupled between the drive means and the tongs for rotating the tongs with a torque T about an axis spaced halfway between and perpendicular to the pair of axes, and power multiplication means operatively coupled between the drive means and the tongs for urging one ends of the tongs into contact with opposite sides of the valve with a torque T where T is greater than T and the tongs tightly hold the valve during turning thereof relative to the cylinder.

OBJECTS It is therefore an object of the present invention to provide a valving machine.

It is a further object of the present invention to provide'a valving machine including self-adjusting, power actuated, valve tongs that provide a positive, non-slip hold on a valve no matter how tight it is.

It is a still further object of the present invention to provide a valving machine which prevents damage to valve parts.

It is another object of the present invention to provide a valving machine including a pair of valve tongs that automatically take up the slack between the gripping surfaces thereof and the valve body.

Still other objects, features, and attendant advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the preferred embodiment constructed in accordance therewith, taken in conjunction with the accompanying drawings wherein like numerals designate like parts in the several figures and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a valving machine constructed in accordance with the teachings of the present invention;

FIG. 2 is an enlarged, sectional view taken along the longitudinal axis of the drive shaft of the machine of FIG. 1;

FIG. 3 is a sectional view taken along the line 3-3 in FIG. 2; and

FIG. 4 is a sectional view taken along the line 4-4 in FIG. 2.

DESCRIPTION F THE PREFERRED EMBODIMENT Referring now to the drawings and, more particularly, to FIG. I thereof, there is shown a valving machine, generally designated 10, for inserting or removing a valve 11 into or from a cylinder 12. Cylinder 12 is of conventional construction including an internally threaded hole at the upper end thereof which receives the threaded stud of valve 11. Thus, insertion or removal of valve 11 into or from cylinder 12 is achieved by holding cylinder 12 stationary and rotating valve 11, as known in the art.

Valving machine includes a base 13 on which is rigidly mounted a support column 14. Intermediate the upper and lower ends of support column 14 is mounted apparatus, generally designated 15, for securely holding cylinder 12 and for preventing rotation thereof. Movably mounted adjacent the top of support column 14 is apparatus, generally designated 30, for engaging the opposite sides of valve 11 and for rotating valve 11. relative to cylinder 12.

Cylinder holding means 15 includes a first arm 16, one end of which has a generally V-shape to engage one side of cylinder 12. The other end of arm 16 is mechanically connected to support column 14 so as to be movable axially relative thereto under control of a first hand wheel 17. Arm 16 is movably connected to support column 14 in any suitable manner to provide for different sizes of cylinder 12. Thus, as the diameter of cylinder 12 increases, hand wheel 17 may be rotated to decrease the length of arm 16 and as the diameter of cylinder 12 decreases, hand wheel 17 may be rotated to increase the length of arm 16.

Cylinder holding means 15 also includes a second arm 19, one end of which is movably connected to a power application unit 20 which is rigidly connected to support column 14 by bracket means 21. The other end of arm 19 is connected by means 22 to an arm 23 positioned coaxially with arm 16. The end of arm 23 facing arm 16 has a generally V-shape to engage the side of cylinder 12 opposite from arm 16.

Power application unit 20 may be a conventional air driven unit for pulling in or pushing out arm 19 under control ofa manual actuator 24 positioned on a control panel 25. Thus, upon manipulation of actuator 25, arm 19 is extended from unit 20 to separate

arms

16 and 23 and to permit removal of cylinder 12. A second hand wheel 26 may be provided to adjust the extended position of arm 19. On the other hand, actuator 24 may be manipulated to cause power application unit 20 to withdraw arm 19, bringing

arms

23 and 16 into contact with the opposite sides of cylinder 12 to securely hold cylinder 12 relative to base 13 and support column 14. Control panel may also include a regulator 27 for controlling the force applied by application unit 20 to arm 19 and a gauge 28 to provide a readout of such force.

Valve rotating means 30 is supported on a head 31 which is movably mounted on support column 14. Head 31 may be moved vertically by a counterbalanced cable and pulley arrangement, so as to adjust the position of valve rotating means 30 relative to base 13 for different sizes of cylinder 12. Head 31 supports control panel 25 and the operating controls for valving machine 10.

Valve rotating means 30 includes a pair of jaw tongs 33 and 34 which extend vertically downwardly from head 31 and are pivotable about a pair of parallel, horizontal, spaced axes defined by

pins

35 and 36, respectively.

Pins

33 and 34 permit ends 37 and 38 of jaw tongs 33 and 34, respectively, to contact the opposite sides of valve 11 to hold valve 11 while it is being rotated to insert or remove same from cylinder 12.

Referring now to FIGS. 24, head 31 supports a drive shaft 40, the axis of which is spaced halfway between and perpendicular to the axes of

pins

35 and 36. Furthermore, the axis of drive shaft 40 is adapted to be aligned with the common axis of valve 11 and cylinder 12. The upper end of drive shaft 40 is connected to air driven power means, not shown, within head 31. Drive shaft 40 is adapted to be operatively coupled to

jaw tongs

33 and 34, by means to be described hereinafter, for rotating

tongs

33 and 34 around shaft 40 to insert or remove valve 11 into or from cylinder 12. Drive shaft 40 is also adapted to be operatively coupled to the other ends 41 and 42 of jaw tongs 33 and 34, respectively, to rotate

tongs

33 and 34 about

pins

35 and 36, respectively, to urge ends 37 and 38 of

tongs

33 and 34, respectively, into contact with opposite sides of valve 1 1.

More specifically, and referring primarily to FIGS. 2 and 3, drive shaft 40 is surrounded by a sun gear 44 which is driven with shaft 40 by means of a key 45 positioned within opposing slots 46 and 47 in the outer surface of shaft 40 and the inner surface of sun gear 44, respectively. Sun gear 44 is surrounded by an annular shaped planetary gear housing 50 which supports a plurality of identical planetary gears 51. More specifically, housing 50 includes a central chamber 52 in which sun gear 44 is mounted and a plurality of outer chambers 53 in which planetary gears 51 are mounted in such a manner that the teeth on planetary gears 51 engage the teeth on sun gear 44. Each of planetary gears 51 is mounted on a shaft 54. Shims 55 may be positioned between gears 51 and housing 50 for spacing and support of gears 51. In addition, bearings 56 may be positioned between sun gear 44 and housing 50 to provide axial support thereof.

Planetary gear housing 50 is mounted between an upper, disc-shaped plate 58 and a lower, disc-shaped flange 59 made integral with or connected to a drive tube 60 which is positioned around drive shaft 40. Planetary gear housing 50 may be connected to plate 58 and flange 59 by means of a plurality of screws 61 which extend through mating holes in plate 58, housing 50, and flange 59, such holes being spaced between chambers 53 in housing 50 so as not to interfere with the operation of planetary gears 51. It should be noted that drive shaft 40 passes through central openings in plate 58, flange 59, and drive tube 60 and is not connected thereto.

Mounted at the lower end of drive shaft 40 is a generally I-I-shaped block 65, the plane of which is perpendicular to the axis of drive shaft 40. I-I-block 65 has a hole 66 passing through the central portion thereof through which the lower end of shaft 40 extends. A bolt 67 extends into an internally threaded bore 68 in the bottom of shaft 40, the head of bolt 67 supporting a plurality of washers 69 which support H-block 65 for rotational movement relative to shaft 40. It is significant to note that there is no connection between H- block 65 and drive shaft 40 other than the rotatable support provided by washers 69.

H-block 65 supports pins 35 and 36 on which jaw tongs 33 and 34, respectively, are pivotably mounted. Thus, rotation of Hblock 65 about the axis of hole 66 will rotate

tongs

33 and 34, as described previously.

l-l-block 65 includes a drive tube 70 made integral with or connected to the central section thereof, drive tube 70 having an inner diameter approximately equal to the outer diameter of drive tube 60, drive tube 70 being mounted coaxially with and surrounding drive tube 60. Drive tube 70 is driven with drive tube 60 by means of a key 71 positioned within opposing

slots

72 and 73 in the outer surface of drive tube 60 and the inner surface of drive tube 70, respectively. Thus, rotation of planetary gear housing 50 about the axis of drive shaft 40 causes rotation of drive tube 60 which, through the intermediary of key 71, causes rotation of drive tube 70 and H-block 65 around drive shaft 40. In this manner, the rotation of drive shaft 40 is transmitted to

tongs

33 and 34, as will be described more fully hereinafter.

Planetary gears 51 and planetary gear housing 50 are surrounded by an annular shaped cam drive housing 75 which supports a ring gear 76. Ring gear 76 is connected to the inner surface of cam drive housing 75 in any suitable manner. The upper end of cam drive housing 75 is spaced from and surrounds the circumference of plate 58. The lower end of cam drive housing 75 is connected to or made integral with a disc-shaped plate 77 which extends beneath flange 59 of planetary drive tube 60. A spacer 78 positioned between plate 77 and ring gear 76 supports ring gear 76 in contact with planetary gears 51, as shown most clearly in FIG. 3. A bearing 79 positioned between the bottom surface of flange 59 and the top surface of plate 77 permits rotation of cam drive housing 75 relative to planetary gear housing 50.

The inner circumference of plate 77 is spaced slightly from the outer surface of planetary drive tube 60. Positioned beneath plate 77 is an elliptically shaped jaw cam 80, shown most clearly in FIG. 4, the plane of cam 80 being perpendicular to the axis of drive shaft 40. Cam 80 has a hole 81 passing through the center thereof through which planetary drive tube 60 passes. Jaw cam 80 is connected to or made integral with plate 70 of cam drive housing 75 so as to be rotatable with cam drive housing 75 and ring gear 76. Furthermore, cam 80 is position so as to be adjacent ends 41 and 42 of jaw tongs 33 and 34, respectively, which terminate adjacent plate 77.

The minor diameter ofjaw cam 80 is equal to or less than the spacing between

tongs

33 and 34 when

tongs

33 and 34 are parallel, as shown in solid lines in FIG. 2. On the other hand, the major diameter of cam 80 is substantially greater so that as cam 80 rotates relative to H-block 65, ends 41 and 42 of

tongs

33 and 34, respectively, are driven outwardly, forcing ends 37 and 38 of

tongs

33 and 34, respectively, towards each other.

Drive shaft 40 is preferably driven by an air motor drive under control of a manual actuator 83 mounted on control panel 25. Thus, movement of actuator 83 to the left will cause rotation of drive shaft 40 in one direction and movement of actuator 83 to the right will cause rotation of drive shaft 40 in an opposite direction. By making cam 80 elliptical, a single unit may be used for tightening or loosening valve 11. Finally, control panel 25 may include a regulator 84 for controlling the force applied to drive shaft 40 and a gauge 85 to provide a readout of such force.

OPERATION In order to operate valving machine 10, actuator 24 is manipulated to release arm 19 so as to separate

arms

16 and 23 to permit cylinder 12 to be inserted therebetween. With valve 11 positioned coaxially with drive shaft 40, hand wheel 17 is manipulated to bring arm 16 into contact with one side of cylinder 12. The desired force on cylinder 12 is adjusted by means of regulator 27 and manual actuator 24 is manipulated to activate power application unit 20. Arm 23 is automatically brought into contact with the other side of cylinder 12, securely holding cylinder 12 and preventing rotation thereof.

The control mechanism within valve rotating means 30 is next activated to bring ends 37 and 38 of jaw tongs 33 and 34, respectively, into contact with the valve flats on the opposite sides of valve 11. Assuming that one is inserting valve 11 into cylinder 12, requiring clockwise rotation thereof, manual actuator 83 is manipulated so as to cause rotation of drive shaft 40 in a clockwise direction, as viewed in FIG. 3. Rotation of drive shaft 40 in this direction causes counterclockwise rotation of planetary gears 51 about shafts 54. Rotation of planetary gears 51 will cause one of two results. Either cam drive housing 75 and ring gear 76 will remain stationary and planetary gear housing 50 will rotate in a clockwise direction or planetary gear housing 50 will remain stationary and cam drive housing 75 will rotate in a counterclockwise direction. Initially, since jaw tongs 33 and 34 will be parallel and out of contact with valve 11, it is desired to prevent the former type of motion and to permit the latter type. Since jaw tongs 33 and 34 are connected directly to planetary gear housing 50 by means of I-l-block 65, drive tube 70, key 71, drive tube 60, flange 59, and screws 61, the rotation of planetary gear housing 50 may be prevented by simply holding l-I-block 33 or one of

tongs

33 and 34 to prevent rotation thereof. For this purpose and also for the purpose of stiffening

tongs

33 and 34, tongs 33 and 34 include outwardly projecting

stiffening members

93 and 94, respectively. Thus, one of stiffening

members

93 or 94 may be held in one hand while actuator 83 is manipulated with the other hand.

With reference to FIGS. 2-4, the clockwise rotation of drive shaft 40 causes counterclockwise rotation of planetary gears 51 about shafts 54. Since planetary gear housing 50 is prevented from rotating, ring gear 76 and cam drive housing 75 are driven in a counterclockwise direction. Rotation of cam drive housing 75 causes rotation of cam 80 through the intermediary of plate 77. Thus, cam 80 rotates relative to drive tubes and 70, driving ends 41 and 42 of

tongs

33 and 34, respectively, outwardly, tongs 33 and 34 pivoting about

pins

35 and 36. This action continues until ends 37 and 38 contact the oppositesides of valve 11. When this occurs, cam 80 and cam drive housing can no longer rotate independently of H-block 65 and

tongs

33 and 34. Thus, with cam securely locked against ends 41 and 42 of

tongs

33 and 34, respectively, and with

ends

37 and 38 of

tongs

33 and 34, respectively, firmly in contact with the opposite sides of valve 11, planetary gear housing 50 and cam drive housing 75 begin to rotate as a unit in a clockwise direction. As explained previously, rotation of planetary gear housing 50 with drive shaft 40 causes rotation of planetary drive tube 60 about the axis of drive shaft 40. Planetary drive tube 60 drives H-block drive tube 70 by means of key 71 resulting in the rotation of l-l-block 65 and

jaw tongs

33 and 34. Thus, tongs 33 and 34 rotate valve 11 relative to cylinder 12.

It should be particularly noted that the just described arrangement of sun gear 44, planetary gears 51, and ring gear 76 results in a power multiplication of the torque generated by drive shaft 40. Thus, the torque T urging ends 37 and 38 of

tongs

33 and 34, respectively, into contact with the opposite sides of valve 11 is multiplied with respect to the torque

T rotating tongs

33 and 34 about the axis of shaft 40. This power multiplication insures that any deformation of valve 11, causing a diminishing of the spacing between the sides thereof, automatically causes slipping of housing 75 relative to housing 50, resulting in a counterclockwise rotation of cam 80 relative to H-block 65 to pivot

tongs

33 and 34 by an amount which will take up such slack. Without this power multiplication, ends 37 and 38 of

tongs

33 and 34, respectively, would be forced to separate and the same problems would be encountered as experienced heretofore.

Many factors influence the power multiplication factor such as the relative diameters of sun gear 44, planetary gears 51, and ring gear 76, the diameter of cam 80, the length of

tongs

33 and 34 relative to the location and spacing of

pins

35 and 36, etc. Suffice it to say that the torque urging ends 37 and 38 of

tongs

33 and 34, respectively, into contact with the opposite sides of valve 11 should be at least twice as great as the torque rotating H-block 65 and

tongs

33 and 34.

After valve 11 has been tightened, actuator 83 is manipulated in the other direction to cause reversal of shaft 40 and pivoting

ofjaw tongs

33 and 34 in an opposite direction so as to release valve 11. Actuator 24 may then be manipulated to release arm 23, permitting removal of cylinder 12.

As stated previously, both power application unit 20 and valve rotating means 30 are preferably air motor drives. This is preferred since the torque can be adjusted by setting air regulators 27 and 84. In addition, an air drive slows as the torque reaches the stall point so that brass valve threads have time to cold flow under pressure and conform themselves to the cylinder neck threads, thus reducing the possibility and nuisance of leaks.

lt can therefore be seen that in accordance with the present invention, there is provided a valving machine which solves the problems encountered heretofore. Valving machine 10 includes a pair of

tongs

33 and 34 pivotable about a pair of parallel, spaced pins 35 and 36, respectively, so that ends 37 and 38 of

tongs

33 and 34, respectively, may be brought into contact with opposite sides of valve 11. With machine 10, tongs 33 and 34 are power actuated and self-adjusting so that a force urges ends 37 and 38, respectively, into contact with valve 11 at all times during rotation thereof. Furthermore, the torque tending to urge

tongs

33 and 34 into 6 contact with valve 11 is greater than the

torque rotating tongs

33 and 34 to insure that the tongs tightly hold valve 11 during turning thereof relative to cylinder 12 thereby preventing slipping thereof and potential damage to valve 11.

While the invention has been described with respect to a preferred physical embodiment constructed in accordance therewith, it will be apparent to those skilled in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrative embodiment, but only by the scope of the appended claims.

I claim: I

l. A machine for rotating a first member relative to a second member comprising:

means for securely holding said second member;

a pair of tongs pivotable about a pair of parallel,

spaced axes;

drive means;

means forming a direct, non-friction connection between said drive means and said tongs for rotating said tongs with a torque T about an axis spaced halfway between and perpendicular to said axes; and

power multiplication means operatively coupled between said drive means and said tongs for urging one ends of said tongs into contact with opposite sides of said first member with a torque T T being greater than T, whereby said tongs tightly hold'said first member during turning thereof relative to said second member.

2. A machine according to claim 1 wherein T is at I least equal to 2T,.

a plurality of planetary gears mounted within said housing and engaging said sun gear; and

means interconnecting said planetary gear housing and said tongs.

6. A machine according to claim 5 wherein said power multiplication means comprises:

a cam drive housing surrounding said planetary gear housing;

a ring gear mounted within and connected to said cam drive housing, said ring gear engaging said planetary gears and being driven thereby; and

cam means connected to said cam drive housing and being rotatable therewith, said cam means contacting the other ends of said tongs and being operative to pivot said tongs about said spaced axes upon rotation of said cam drive housing relative to said planetary gear housing.

7. A machine according to claim 6 wherein rotation of said drive shaft causes rotation but not translation of said planetary gears, causing rotation of said ring gear and said cam drive housing thereby rotating said cam means and pivoting said tongs about said spaced axes means urges said one ends of said tongs into contact until said one ends of said tongs contact said opposite with said opposite sides of said first member.

sides of said first member, additional rotation of said 8. A machine according to claim 4 wherein said drive shaft causing rotary translational movement of means for rotating said shaft comprises:

said planetary gears and said ring gear about said drive 5 an air motor.

shaft axis thereby rotating said tongs while said cam

Claims

1. A machine for rotating a first member relative to a second member comprising: means for securely holding said second member; a pair of tongs pivotable about a pair of parallel, spaced axes; drive means; means forming a direct, non-friction connection between said drive means and said tongs for rotating said tongs with a torque T1 about an axis spaced halfway between and perpendicular to said axes; and power multiplication means operatively coupled between said drive means and said tongs for urging one ends of said tongs into contact with opposite sides of said first member with a torque T2, T2 being greater than T1 whereby said tongs tightly hold said first member during turning thereof relative to said second member.

2. A machine according to claim 1 wherein T2 is at least equal to 2T1.

3. A machine according to claim 1 wherein said power multiplication means is operatively coupled between said drive means and the other ends of said tongs, said parallel axes intersecting said tongs between said opposite ends thereof.

4. A machine according to claim 1 wherein said drive means comprises: a shaft positioned coaxially with said axis; and means for rotating said shaft.

5. A machine according to claim 4 wherein said tongs rotating means comprises: a sun gear mounted on said drive shaft; a planetary gear housing surrounding said sun gear; a plurality of planetary gears mounted within said housing and engaging said sun gear; and means interconnecting said planetary gear housing and said tongs.

6. A machine according to claim 5 wherein said power multiplication means comprises: a cam drive housing surrounding said planetary gear housing; a ring gear mounted within and connected to said cam drive housing, said ring gear engaging said planetary gears and being driven thereby; and cam means connected to said cam drive housing and being rotatable therewith, said cam means contacting the other ends of said tongs and being operative to pivot said tongs about said spaced axes upon rotation of said cam drive housing relative to said planetary gear housing.

7. A machine according to claim 6 wherein rotation of said drive shaft causes rotation but not translation of said planetary gears, causing rotation of said ring gear and said cam drive housing thereby rotating said cam means and pivoting said tongs about said spaced axes until said one ends of said tongs contact said opposite sides of said first member, additional rotatioN of said drive shaft causing rotary translational movement of said planetary gears and said ring gear about said drive shaft axis thereby rotating said tongs while said cam means urges said one ends of said tongs into contact with said opposite sides of said first member.

8. A machine according to claim 4 wherein said means for rotating said shaft comprises: an air motor.