US2577068A

US2577068A - Well packer

Info

Publication number: US2577068A
Application number: US685022A
Authority: US
Inventors: Reuben C Baker
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1946-07-20
Filing date: 1946-07-20
Publication date: 1951-12-04
Anticipated expiration: 1968-12-04

Description

2 SHEETS-SEET l Dec. 4, 1951 Filed July 20, 1946 Bfll/l C-Bmet INVENTOR ATTORNEY Patented Dec. 4, 1951 UNITED WELL PACKER Reuben C. Baker, Coalingee Calii-Z, assignor to Baker Oil Tools, Inc.,- Vernon, Calif., a corporation of California- 17 Claims. 1

This invention relates to well tools, and more particularly to subsurface well tools employed in the performance of cementing, acidizing, testing, circulating, anchoring, production and similar functions in well bores.

An object of the invention is to provide a well tool of simple construction and operation which can be anchored readily in a well bore against upward movement and easily released fromsuch anchored condition for elevation in the well bore.

Another object of the invention is to effect anchoring of a well packer against upward movement in a well bore and close an associated control valve by subjecting them to a downward thrust, release from anchored position being easily accomplished and opening of the valve efiected upon upward movement of the packer.

Still another object of the invention is to provide an improved well packer apparatus utilizing its packing structure for controlling flow of fluid in, around and through the apparatus.

Yet a further object of the invention ist'oprovide a well packer apparatus capable of being anchored in a: well bore against upward movement and positively releasable from such anchored condition despite the presence of high pressures in the well tending to maintainithe anchored condition of the apparatus.

'Another object of the invention is to provide an improved packing structure for a well jpacker capable of forming part ofacircula'tion control valve.

Still another object of theinvention is to 'provide a well packer capable of being anchored against upward movement in a well bore, whose anchoring lements are held automatically in retracted position and whose valve mechanism is held open automatically during upward movement of the packer in the well bore.

9 The invention has other object that will- 10ecome apparent from aconsideration of the embodiment shown in the drawings accompanying and forming part of the present specification. This form will now be described in detail, but it is to be understood that such detailed description is not to be taken in a limited "sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a longitudinal view of a well packer embodying. the invention located in a well casing, with its anchoring elements retracted position;

Figurev 2 is. a partial longitudinal sect-lion ofpart of the well packer shown in Figure 1-;

'2 Figure 3 is a view similar to Figure 1, showing the well packer anchored against the well \cas- Figure 4 is a cross-section taken along the line i -'4 in Figure 1; and

Figure-,5 is a 'crossesection taken along the line Er -5 in Figure 1.

The: embodiment of the invention shown in the drawings includes a well packer apparatus A designedto' berunin-well casings or similar conduits B on the lower end of a string of tubing or drill pipe C, and .to be anchored to the casing in packed oif position against upward movement.

The well packer includes an upper outer mandrel t8 telescopically arranged with respect toxa lower inner mandrel or body member l .l threadedly secured to an intermediate body member l2 having upwardly and inwardly directed tapered surfaces i3 cooperating withslips M having companion tapered surfaces I155. The slips are movable outwardly along the inclined faces of the intermediate body member or expander 1:2 into anchoring engagement with the conduit (1, and have upwardly directed wickers designed to penetrate the casing wall and prevent upward movement of the packer apparatus. Side seals it are mounted in the outer mandrel IE] in slidable leakproof engagement with the 'exterioro'f the inner mandrel H to prevent leakage therebetween.

A lower tubular body member or valve body I? is threaded or otherwise suitably secured in the lower endof the intermediate body expander member [2, and has one or more side portsor outlets [-8 adjacent the lower end of the intermediate body member through which fluid may flow between the interior and exterior of the well apparatus. A valve sleeve i9 is slidably mounted on the ported valve body, with a generally cupshaped or similar packing 263 secured to it, which faces downwardly, with its free end slidably engageable with the wall of the casing to prevent upward passage of fluids between the valve sleeve [9f and easing wall."

The packing member 20, of rubber or equivalent material, may be secured to the valve sleeve 1.9 in any suitable manner. As shown in the drawings, a perforated flange 2| is welded on the sleeve, on which an abutment ring 22 is threaded in spaced relation to the exterior of the valve sleeve above the flange. The packing cup 29 is molded on the sleeve and extends through the flange perforations ,or holes 23 to the other side of the flange 2i, thereby firmly anchoring: it to the sleeve 19-. A valve-seal ring 24, of rubber or similar material, is also disposed between the ring 22 and valve sleeve I9, being provided with an end, circular, inwardly directed lip 25 adapted for engagement with the lower end 26 of the intermediate body member I2 to effect a seal therewith whenever the ports I8 are to be closed. The valve seal ring 24 may be molded integrally with the packing cup 20, if desired.

Relative downward movement of the valve sleeve I9, packing cup 20 and valve sealing member 24 along the valve body I1 is limited by engagement between an inner shoulder 21 on the valve sleeve with an outer shoulder 28 on the valve body. When in this position, the lip seal 25 and sleeve I9 are disposed below the ports or outlets I8, permitting circulating fluid pumped down the tubular string B, mandrel I9 and body II, I2, I! to pass outwardly into the annulus between the apparatus and easing wall, for passage around the tubular string to the top of the well bore. Relative elevating movement of the valve sleeve I9 and its attached packing cup 20 and valve packing 24 upwardly along the valve body I! will produce closing of the ports I8 upon engagement of the valve ring 24 with the intermediate body sealing surface 28, preventing outward passage of fluids from within the body through the ports I8. Fluid under pressure acts outwardly against the lip 25 to press it upwardly against the body seal surface 26, preventing leakage past the lip seal.

Relative movement between the parts just referred to may be effected by moving the valve body II down, the valve sleeve I9, seal ring 24 and packing 20 tending to remain immovable by the frictional engagement of the packing cup 23 with the casing wall. This frictional force of engagement, if insufficient may be supplemented by a suitable casing engaging drag device 29, including outwardly bowed springs 39 frictionally engageable with the wall of the casing C. The drag springs are coupled together for joint operation, their lower ends being suitably secured to a lower collar 3|, as by an encircling ring 32 and screws 33, and their upper ends to an upper collar 34 by an encircling ring 35 and screws 33. The connection between the drag device 29 and valve sleeve I9 is efiected by threadedly attaching the upper drag collar 34 to the lower end of the sleeve I9.

The ports I8 may be closed upon lowering of the valve body I! with respect to the valve sleeve I9, to bring the valve ring 24 into engagement with the body sealing surface 26. Conversely, the

ports I8 may be opened by elevating the valve .body IT with respect to the valve sleeve I9. The

piece 31 to the upper collar 34 of the drag device, 7 extending across and engageable with the lower end IIa 'of the valve body I1. When the valve sleeve I9 is in its lowermost position on the valve body H, the

shoulders

21, 28 abut to prevent fur- .ther downward movement of the sleeve I9 on the body IT. The engagement of the cross-piece 31 with the lower end IIa of the valve body prevents relative upward movement of the valve sleeve along the latter. The

shoulders

21, 28 and crosspiece 31 thus prevent relative movement between the valve sleeve and valve body in both longitudinal directions, the ports I8 remaining un covered and fully open to the passage of fluid in either direction between the interior and exterior of the well apparatus.

When the ports I8 are to be closed, the turning of the valve body I7 relative to the valve sleeve I9 aligns the cross-piece 31 with a longitudinally extending valve body slot 38, and permits the body IT to be lowered with respect to the valve sleeve I9 over the cross-piece 31 to produce engagement of the lip seal ring 24 with the intermediate body member I2, thereby closing the ports I8. The drag device 29 tends to hold the valve sleeve I9 and the cross-piece 31 stationary, allowing turning of the valve body IT, as in a clockwise direction (looking down), to engage a depending alignment lug 39 at the lower end of the valve body with the cross-piece and align it with the slot 38, whereupon lowering movement of the valve body I1 is permitted by entry of the cross-piece 31 into and along the slot 39, and the intermediate body 32 secured to the valve body may be engaged with the seal ring 24 to effect closing of the valve.

The slips I4 are mounted for movement in unison by being coupled to a slip ring 43 through the agency of links 4|, whose lower ends are pivotally connected to the slips by pins 42 and whose upper ends are also pivotally attached to the slip ring by pins 43. The slip coupling ring or sleeve 4|] is secured releasably to a tubular slip and valve actuator 44 threadedly attached to the telescopic upper mandrel I8, and, in effect, forming a part thereof. The actuator 44 is spaced from the inner mandrel or body II and extends over a cylindrical sleeve 45 suitably secured to the inner mandrel II, as by welding material, with the lower end or" the actuator having an inwardly directed head 46 below the sleeve 45 adapted to engage its lower end. One or more longitudinal keyways or grooves 41 are formed in the head for reception of lower keys 48 secured on the inner mandrel II, alignment between the keyways and keys bein obtained by lugs 49 depending from the actuator 44 between the keys 48 and engageable with their sides.

The slip coupling ring or sleeve 40 is preferably releasably connected to the tubular actuator 44, its lower end being engageable with a lower shoulder 53 on the actuator. The latter member has a peripheral groove 5I in which one or more coupling balls 52 may be engaged. These are located within pockets 53 in the coupling sleeve 48, containing springs 54 bearing against the balls 52 and against plugs 55 threaded into the sleeve. The springs 54 tend to maintain the balls 52 in the groove 5I, but downward movement of the actuator 44 with respect to the slip sleeve 40 can take place upon overcoming the force of the springs.

The tool is secured to the tubular string with the valve in open position, as determined by misalignment of the cross-piece 31 with its cooperable slot 38, the cross-piece engaging the lower end IIa of the valve body to hold the valve open during lowering of the tool in the well casing. Similarly, the slips I4 are in retracted position on their tapered expander I2 and cannot move outwardly during lowering of the tool in the casing, because of misalignment of the keys 48 with respect to the keyways 41. Instead of allowing the "keys 48 to enter the keyways, their upper ends engage the lower end 44a of the tubular actuator 44. The slip ring 49 is coupled to the telescopic upper mandrel I0 and its actuator 44 by engagement of the balls 52 in the peripheral recess 5|.

5 "Thus, relative movement between the valve sleeve 19 and -valve"body "I'Land betweenthe slips f4 and expander 12, are prevented during downward movement of the well packer apparatus A in the casing since the engagement of the cross-piece 31 with the "underside Iia'of the valve body prevents relative upward travel of the valve sleeve f9 on the body H and engagement of the lower end 44d of the-actuator with the "up'pe'r'ends of the ke s 4"8 prevents the slips M from moving downwardly along the tapered expander I 2, in 'view of the attachment of the keys to the inner mandrel 'l'l, which is threadedly secured to the expander 12. During lowering of the well packer, the fluid may by pass around the packing 2 B and the tool by flowing upwardly into the lower body member 'i'l and-out through the open ports 13.

When the tool has been lowered to the desired poii'it 'in the 'well bore at which it is to be anchored, the tubular string B is rotated clockwise (looking down) to rotate its attached upper mandrel f0 and actuator it inthe same'direetion with respect to the body 11, until the actuator lugs 49 engage the keys 48, whereupon the rotary movement is transmitted to the inner mandrel H and taperedexpander 12 to the lower valve body member I1,'turning it with respect to the cross-piece i7 andits attached valve sleeve i 9, and the packing '20 and seal ring 24 "secured thereto. Such relative turning occurs because the latter members are prevented from rotating by virtue of the di'agspri'ng "3'0 and'packing 2'0 engagement with the casing C. h 7

Turning of the 'valve body I! continues until its depending locating lug 39 engages the crosspiece 31, aligning the "latter with the longitudinal slot 38. The tubular string may now be lowered, to correspondingly shift the apparatus downwardly, with the exception of the valve sleeve 19 and "its attached parts, which are held stationary by 'thedrag device 29. The'cross pie'c'e 31 passes ihto the slot '38, allowing-thevalve body 11 t move down within the valve sleeve 19, until the

lip seal

21, 25 "firm1y'engages its companionseating surfaceZBat the lower end of the intermediate body member "l2. Such engagement causes the drag device 29 'toresist further downward 'mo'veineiitf'of the intermediate body member l2 and it at- 'tached inner'mandrel l I, allowing the telescopic uppermandrel l0 and actuator' fll, together with the'slip ring 40 coupled to it, and the depending links '4'! and slips It, to be moved ddwnwardly with respect to the expander 12, slidingthe slips 1'4 along'th'e tapered "surfaces 13 of the expander and laterally 'outward into engagement with the the slip ring toward the expander l2. In effect,

removal of the balls :52 iromthe groove 5| disconnects theslips l4 and slip-ring M iromtheactuator 44- and its telescopic upper mandrel 1 0.

W Since the ports is have now been closed and the slips M engaged with the casing, the subjection of the fluid in the tubular string 3 and well apparatus A topressurerproduces an-upward hydraulic force on the packing cup 20, which tends 'to wedge the abutting expander 12 upwardly within the slips 15,-anchoring the latter firmly in "the'wall' 0f the casing C.

After-the desired operation has-been performed in the wii bore, the tubuiar strin n may be lowered sufiiciently to move the upper mandrel HI and its actuator 44 downwardly and cause the lower end of the lugs 49 to strike against the upper end "of the expander 1*2, drivingit downwardly (only a slight distance "is sufficient) out of wedging relation with the slips M and freeing them from anchoring engagement with thecasing- C. Thereafter, the tubular "string B may be raised to elevate the upper mandrel It and its actuator 44 along the inner mandrel I slips and their links 41, until the shoulder 50 on the actuator en ages the lower end of the slip ring d'fland'the balls 52 reengagethe groove'5'1. Such engagement of the shoulder 50 causes the upward pulling of the outer mandrel HI to be transmitted to the slips M, sliding them upwardly "and in wardly of the tapered expander l2 to retracted position.

Following retraction of the -slips, the actuator head 66 engages the inner mandrel sleeve 45, transmitting the upward motion of the outer mandrel 10 to the inner mandrel II, and to its attached tapered expander 12 and valve body I 1, moving the latter upwardly with respect to the valve sleeve l'9'to open theports I8. As the valve body T1 rises, its shoulder 28 contacts "the sleeve shoulder '27 and moves the sleeve '19 and its attached parts 20, 2 1, 29, etc. upwardly. The ports [8 are now open, and circulating fluid may 'be pumped down the tubing string B, "through the ports [8 and up the tubing-casing annulus. The circulating fluid may also be pumped down the tubing-casing annulus for passage through "the ports IB into the tool, and upwardly through the tubing string to the top of the well bore.

Following cleaning of the tool by'the circulating fluid, the tubular string B maybe elevated to raise the whole tool to the surface of -the bore. During such raising movement the slips [4 are automatically urged and held in retracted position and the valve ports [8 are automatically held open, since a direct upwardlpullis transm'ittedto the slips l4 and expander [2 simultaneously, allowingino tendency to occurfor wedg'ing upward movement of the expander in'the slip-s. The upward movement also holds the ports '18 elevated above the packing ring 24 and valve sleeve [9, since the latter tend to occupy a lower position, because .of the frictional dragging .of the. springs 30 and packing 20 on the casing wall.

It is, accordingly, apparent that an apparatus has been provided of relatively simple construction; one which is safe to use, since thereisno danger ofthe slips M being movedinto anchoring engagement with the casing during upward movement of the tool therein. Upward movement holds the slips in retracted position and also maintains the valve in open position to permit by-passing of =fluid around the packing cup. Pressures acting-upwardly on the packing cup 20 and tending to hold the slips I l in anchored-en- ;gagementwith theeasing are readily overcome-by downward-movement of the tubular string B and mandrel 'I 0, to deliveri'a striking blow a'gainstthe upperend of'the tapered expander i2 and driveit slightly downwardly of the slips M a suificient distance itorelease the latterfrom the well casing, whereuponpupwar'd:movement of the uppermandrel I'll-positively moves the-slips inwardly-ofthe tapered expander :l2.

Having thus described 'my invention, what I claim and desire tossecure bysLetters Patent is:

.*1.A-t001 'for use'ina well conduit, including i'por-ted tubular means having an routwardly "ere tending sealing surface disposed on one side of its port and transversely to the axis of said tubular means, packing means on said tubular means engageable with said well conduit and disposed on the other side of said port to permit flow of fluid therethrough, said tubular means being movable within said packing means to engage said packing means with said transverse sealing surface and close said port by axially compressing said packing means against said sealing surface.

2. A tool for use in a well conduit, including ported tubular means having an outwardly extending sealing surface disposed on one side of its port and transversely to the axis of said tubular means, packing means on said tubular means engageable with said well conduit and disposed on the other side of its port to permit flow of fluid therethrough, said packing means having an inwardly directed circular lip engageable with said transverse sealing surface to close said port by axially compressing said lip against said sealing surface.

3. A tool for use in a well conduit, including ported tubular means having an outwardly extending sealing surface disposed on one side of its port and transversely to the axis of said tubular means, a valve sleeve slidable on said tubular means, conduit engaging packing means secured to said sleeve, and elastic, pliant seal means secured to said sleeve and engageable with said transverse sealing surface to close said port by axially compressing said seal means against said sealing surface.

4. A tool for use in a well conduit, including ported tubular means having an outwardly extending sealing surface disposed on one side of its port and transversely to the axis of said tubular means, a valve sleeve slidable on said tubular means, conduit engaging packing means secured to said sleeve, elastic, pliant seal means secured to said sleeve, and cooperable releasable lock means on said tubular means and sleeve for holding said seal means for engagement with said surface to permit fluid flow through said port, said lock means being releasable to allow relative longitudinal movement between said tubular means and sleeve to bring said seal means and transverse sealing surface into engagement with each other to close said port by axially compressing said seal means against said sealing surface.

5. A tool for use in a well conduit, including ported tubular means having an outwardly extending sealing surface disposed on one side of its port, a valve sleeve slidable on said tubular means, conduit engaging packing means secured to said sleeve, seal means secured to said sleeve, said tubular means having a longitudinal slot, a cross-piece secured to said sleeve and engageable with an end of said tubular means to hold said seal means from engagement with said surface to permit fluid flow through said port, said cross-piece being movable within said slot to allow relative longitudinal movement between said tubular means and sleeve and engagement of said seal means with said sealing surface to close said port.

6. A tool for use in a well conduit, including inner and outer telescopically arranged body members, said outer body member being connectable to a running-in string, an expander on said inner body member, slips cooperable with said expander, means releasably coupling said slips to the outer body member for movement with said outer body member, lock means on said body members for holding said slips in retracted position by preventing their movement with respect to said expander, said outer body member being rotatable in response to movement of said running-in string to release said lock means and allow said outer body member to move said slips longitudinally along said expander and outwardly into engagement with said conduit, whereupon said coupling means is releasable to allow said outer body member to move longitudinally of said slips.

'7. A tool for use in a well conduit, including inner and outer telescopically arranged body members, said outer body being connectable to a running-in string, an expander on said inner body member, slips cooperable with said expander, means releasably coupling said slips to the outer body member for movement with said outer body member, one of said body members having a key and the other of said body members having a groove, said key engaging the other of said body members when disaligned from said groove to prevent movement of said slips with respect to said expander, and said key entering said groove when in alignment therewith to permit said outer body member to shift said slips longitudinally along said expander and outwardly into engagement with said conduit, whereupon said coupling means is releasable to allow said outer body member to move longitudinally of said slips.

8. A tool for use in a well conduit, including inner and outer telescopically arranged body members, said outer body member being connectable to a running-in string, an expander on said inner body member, slips cooperable with said expander, means releasably coupling said slips to the outer body member for movement with said outer body member, one of said body members having a key and the other of said body members having a groove, said key engaging the other of said body members when disaligned from said groove to prevent movement of said slips with respect to said expander, and means for aligning said key with said groove upon relative rotation between said body members to permit entry of said key in said groove and to thereby allow said outer body member to shift said slips longitudinally along said expander and outwardly into engagement with said conduit, whereupon said coupling means is releasable to allow said outer body member to move longitudinally of said slips.

9. A tool for use in a well conduit, including inner and outer telescopically arranged body members, said outer body being connectable to a running-in string, an expander on said inner body member, slips cooperable with said expander, means releasably coupling said slips to the outer body member for longitudinal movement with said outer body member and to allow longitudinal movement of said outer body member relative to said slips, and releasable lock means on said body members for initially holding said slips in retracted position by preventing their movement with respect to said expander.

10. A tool for use in a well conduit, including inner and outer telescopically arranged body members, an expander on said inner body member, slips cooperable with said expander, automatically releasable means for coupling said slips to said outer body member, releasable lock means on said body members for initially holding said slips in retracted position by preventing their movement with respect to said expander, said lock means being releasable upon rotation of said outer body member to allow said outer body member to move said slips longitudinally along said expander and outwardly into engagement with said conduit, said outer body member being released from said slips upon engagement of the latter with said conduit to permit said outer body member to move longitudinally into engagement with said expander.

11. A tool for use in a well conduit, including a ported tubular body, packing means on said tubular body engageable with said well conduit and adapted to close the body port upon downward movement of said body in said packing means, an expander on said body, slips cooperable with said expander, a mandrel telescopically arranged with respect to said body, means coupling said slips for movement with said mandrel, lock means on said body and packing means for preventing downward movement of said body in said packing means, lock means on said mandrel and body for preventing downward movement of said slips along said expander, both of said lock means being releasable in response to rotation of said mandrel to permit said mandrel to move said body downwardly of said packing means to close said port and to move said slips downwardly along said expander into engagement with said conduit.

12. A tool for use in a well conduit, including a ported tubular body, packing means on said tubular body engageable with said well conduit and adapted to close the body port upon downward movement of said body in said packing means, an expander on said body, slips cooperable with said expander, a mandrel telescopically arranged with respect to said body, means coupling said slips for longitudinal movement with said mandrel, said body having a slot and said packing means having a cross-piece initially engageable with the end of said body to prevent downward movement of said body along said packing, said mandrel having a keyway and said body having a key initially engaging said mandrel to prevent downward movement of said slips along said expander, and means on said mandrel and body for aligning said key with said keyway and said cross-piece with said slot upon rotation of said mandrel to permit downward movement of said body within said packing means to close said port and downward movement of said slips along said expander into engagement with said conduit.

' 13. A tool for use in a well conduit, including inner and outer telescopically arranged body members, said outer body member being connectable to a tubular running-in string, an expander on said inner body member, slips cooperable with said expander for anchoring said tool to said conduit against upward movement, means releasably coupling said slips to the outer body member for movement with said outer body member, lock means on said body members for holding said slips in retracted position by preventing their movement with respect to said expander, said outer body member being rotatable in response to rotation of said tubular running-in string to release said lock means and allow said outer body member to move said slips longitudinally along said expander and outwardly into engagement with said conduit, whereupon said coupling means is releasable to allow said outer body member to move longitudinally of said slips.

14. A tool for use in a well conduit, including inner and outer telescopically arranged body members, an expander on said inner body member, slips cooperable with said expander for anchoring said tool to said conduit against upward movement, automatically releasable means for coupling said slips to said outer body member, releasable lock means on said body members for initially holding said slips in retracted posiion by preventing their movement with respect to said expander, said lock means being releasable upon rotation of said outer body member to allow said outer body member to move said slips longitudinally along said expander and outwardly into engagement with said conduit, said outer body member being released from said slips upon engagement of the latter with said conduit to permit said outer body member to move longitudinally into engagement with said expander.

15. A tool for use in a well conduit, including a ported inner body member, an outer body member telescoped over said inner body member, an expander on said inner body member, slips cooperable with said expander, means coupling said slips to the outer body member for movement with said outer body member, releasable lock means on said body members for initially holding said slins in retracted position by preventing their movement with respect to said expander, and packing means on said inner member engageable with said well conduit and movable longitudinally relative to said inner member and slips to close the port in said inner member.

16. A tool for use in a well conduit, including inner and outer telescopically arranged body members, an expander on said inner body, slips cooperable with said expander, automatically releasable means for coupling said slips to said outer body member for movement by said outer body member along said expander and outwardly into engagement with the well conduit, said outer body member being released from said slips upon engagement of the latter with said conduit to permit said outer body member to move longitudinally into engagement with said expander.

17. A tool for use in a well conduit, including inner and outer telescopically arranged body members, an expander on one of said body mem-- bers, slips cooperable with said expander, automatically releasable means for coupling said slips to the other of said body members for movement by said other of said body members along said expander and outwardly into engagement with said conduit, said other of said body members being released from said slips upon engagement of the latter with said conduit to permit said other of said body members to move longitudinally into engagement with said expander.

REUBEN C. BAKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,001,684 Johnson May 14, 1935 2,023,930 Mackowski Dec. 10, 1935 2,225,143 Baker et al Dec. 17, 1940 2,292,345 Arutunoff Aug. 11, 1942 2,390,112 McGafiey Dec. 4, 1945