US2836016A

US2836016A - Apparatus for opening hermetically sealed casings

Info

Publication number: US2836016A
Application number: US601719A
Authority: US
Inventors: Lowitz Frank
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-08-02
Filing date: 1956-08-02
Publication date: 1958-05-27
Anticipated expiration: 1975-05-27

Description

May 27, 1958 F. howl-rz 2,836,016

APPARATUS FOR OPENING HERMETICALLY SEALEDA CASINGS Filed Aug. 2, 1956 "PL I \\O 3 Sheets-Sheet 1 uw E; w *bi1/.1 @f llll IllmmulIIIHIWNMHW,I

R04' I lob JNVENTOR.

Anne/vas May 27, A1958 F, LowlTz 2,836,016

APPARATUS FOR OPENING HERMETICALLY SEALED CASINGS Filed Aug.I 2, 1956 I jl l ."0 \OO u lIEx qo 3 Sheets-Sheet 2 T ic'. Z.

INVENTOR. )CkqA/K Z o W/TZ A TTOPYEYS May 27, 1958 F. LowlTz 2,836,016

APPARATUS FOR OPENING HERMETICALLY SEALED CASINGS Filed Aug. 2, 1956 3 Sheets-Sheet 5 numllml JNVENTOR. FHNK ow/TZ United States Patent G APPARATUS FR OPENING HERNEETICALLY SEALED CASlNGS Frank Lowitz, Bronx, N. Y.

Application August 2, 1956, Serial No. 601,719

16 Claims. (Cl. 51-105) This invention relates to an apparatus for opening hermetically sealed casings. The present invention is an improvement over the invention disclosed in my copending application Serial No. 430,242 for Means for Opening Hermetically Sealed Casings iiled May 17, 1954, now United States Letters Patent No. 2,775,852, issued January l1, 1957.

As pointed out in my said copending application, it has been the practice in the eld of refrigeration units, and particularly compression refrigeration units which are employed in domestic refrigerators, dehumidifiers, air conditioners, and the like, to provide a so-called sealed unit which includes an electric motor and a compressor housed within a casing. The casing consists of two parts having matching open ends which are intertted and welded together along a continuous seam, e. g. a circular or oval seam. Electric wires and gas lines extend to the motor and compressor through suitable openings in the casing. However, due to the nature of the connection between the two parts of the casing, if any trouble develops in either the motor or the compressor the entire sealed unit is considered to be de festive and is discarded and replaced as a whole.

lt has been the practice in general to treat the discarded units as junk and to consider them as Worthless because of the diiculty attendant upon the opening of the casing in order to provide access for removal and repair of the motor and/ or the compressor. Even where equipment is available for opening up a unit, such equipment constituting, for example, a lathe or a heavy hand grinder, it takes a man so long to open the unit, that, taking into consideration the fact that the motor or compressor may be beyond practical repair, it is rare that compression units are salvaged.

It will be appreciated that the aforesaid equipment requires the constant attendance, guidance and skill of a man to open up a unit. The metal removing tool must be continuously guided so as to follow the Weld seam and to remove metal therefrom without destroying the casing. A conventional tool, such as a lathe or surface grinder, which revolves the work with relation to a fixed metal removing element is particularly difficult to employ for the foregoing purpose since the seam never is regular and since the shapes of the seams vary from unit to unit requiring special set-ups that are too expensive to make in automatic machinery when measured against the value of the parts to be recovered.

It is an object of the present invention to provide an improved, simple, rugged, easy-to-operate machine for opening hermetically sealed units.

More specically, it is an object of my invention to provide a machine of the character described which can open the welded seams of two-part hermetically sealed casings of the type commonly employed in domestic compression refrigeration systems, the opening being effected with minimum mutilation of the casing parts, with a minimum set-up time and without constant care of the men.

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It is another object of my invention to provide an apparatus of the character described having controls whichare so simplified that the apparatus can be set up and run by unskilled labor.

It is another object of my invention to provide an apparatus of the character described which can with very few and very simple changes be adapted to open sealed units of known sizes, shapes and types.

It is another object of my invention to provide an apparatus of the character described Which can open compression refrigeration units having either non-centered or asymetric welded seams joining their two casing parts.

It is another object of my invention to provide an apparatus of the character described in which it is not necessary to center the casing with any great degree of accuracy preparatory to opening the same.

1t is another object of my invention to provide an apparatus of the characterv described which when once set up and started in operation can be left alone without danger of mutilating the casing parts beyond re-use.

It is another object of my invention to provide an apparatus of the character described which, without compleX parts or circuity, will stop removing the metal of the casing or of the weld at a predetermined depth of grinding. Y

It is another object of my invention to provide an apparatus of the character described which can automatically follow highly irregular weld seams, for example, weld seams which deviate from a horizontal plane and are asymetric in plan.

it is another object of my invention to provide an apparatus of the charcter described having a metal removing tool, such as a grinding wheel, which is shiftably iloatable in more than one plane at a time, whereby to enable it automatically to follow a complex shape of Welded seam without special controls or set-ups.

Other objects of my invention in part will be obvious and in part will be pointed out hereinafter.

My invention accordingly consists in the features of construction, combinations of elements and arrangements of parts which will be exemplified in the machine hereinafter described and of which the scope of application will be indicated in the appended claims.

In the accompanying drawings, in which is shown one of the various possible embodiments of my invention,

Fig. 1 is a front view of a machine constructed in accordance with the invention and arranged, i. e., set up, to operate on a sealed unit having a laterally facing welded parting seam;

Fig. 2 is an enlarged fragmentary front view of the sealed unit shown in Fig. l and of the table and clamping means for supporting and turning said unit, portions of the unit and clamping means being broken away to illustrate certain details;

Fig. 3 is an enlarged sectional view taken substantially along the line 3 3 of Fig. 1, and showing certain details of the mechanism for adjusting the height of the grinding wheel;

Fig. 4 is a sectional view taken substantially along the line 4 4 of Fig. 3;

Fig. 5 is a sectional view taken substantially along the line 5 5 of 1Eig. 4;

Fig. 6 is an enlarged fragmentary view of the grinding motor support, the same being taken along the line 6 6 of Fig. 1, and having portions thereof broken away in order better to illustrate various structural details;

Fig. 7 is an enlarged sectional View taken substantially along the line 7 7 of Fig. 1;

Fig. 8 is a top view of the frame for the grinder wheel motor, the same being seen as viewedy along the line 8 8 of Fig. 6;

Fig. 9 is a sectional view taken substantially on the line 99 ofFig. 6;

Fig. l() is a fragmentary `perspective'view of a portion of the feeler associated with the grinding wheel; Fig. ll is a view similar to Fig. ,l of the machine as it appears when set up to operate on Ya sealed unit having an upwardly facing welded parting seam; and

Figi 12 is a fragmentary enlarged -view taken substantiallyalong the line 12-1'2 of Fig. 1l, the lmotor `being ,omitted ,for the sake of clarity.

Referring now in detail tothe drawings, the reference numeral 2,0 denotes a machine constructed in accordance Vwith 'my invention. 'Said machine .includes a frame consttlltng a base 22-and a bridge. 24, the latterconsisting of pairs of Vlegs 2,6 yat opposite sides of the machine and a pair of parallel spans 28` connecting the upper ends of the legs.

YThe machine .further includes a rubber-covered work table `3ft) which is adapted to holdand ,turn a `compression refrigeration unit, such forinstance as the unit 32, located in proper position for performance of .a grinding operation thereon. The work table has a downwardly dependingcentral stem 34 which is affixed to the low speed output shaft (not shown) of a rotary driving VYunit housed within the .base 2 2; The driving unit mayk conventionally comprise an electric motor which turns the stem 34 through. a suitable gear reduction train, the filtration of ciently versatile to handle both of the foregoing typesY operation of said ,motorY and of the grinding motor here- Y Y inafter described being set by a timer under the contro-l of a knob 36 which ismounted on the front of the base rfor convenience.Y An off-on switch 38 near the knob 36 'is provided to Vcontrol the table motor.

Y VAhold downrpin 40 is carried by an anti-friction bearing 42 for rotation about a vertical axis coincident with Vthe axis of rotation of the table 30. The outer race of .the .bearing is secured in the lower cupped end 44 by a threaded adjusting shaft 46, the upper end of which is screwed `into a vertically tapped block 48 fixed between the spansr28. VvIt will be appreciated that by rotating the shaft 46l the vertical position of the pin 40 can be .set to any desired height.

I furtherprovide for Vuse in connection with the table a sleeve 50. Y

The Vtypical sealed unit 32 which is shown in Fig. l .is set up vby placing the sleeve 5.0 .on the work table in a substantially central location. The unit has its large convex bottom disposed on the sleeve and is manipulated to locate its laterally facing welded parting seam 52 in a substantially horizontal plane with the center of the unit substantially coincident with the vertical axis of rotation of. the table. It may be Vmentioned that satisfactory operation of Vthe grinder does not require absolute centering or levelling of the parting seam. The pin 40 is lowered by rotation of the shaft .4.6, `to clamp the unit between said .P111 and the table. It will be appreciated that it thus is possible quickly to set up and secure a unit on the work table. 'l

As is conventional, the sealed unit 32 constitutes a casing that includes two interitted parts, to wit: a lower part V54 and an upper part 56. The adjacent portions Aof these two parts have outwardly extending flanges, the peripheries of which are abutted along the laterally outwardly facing partingseam 52 that is closed byf a bead of Weld deposited metal. It is this bead which must be removed in order to separate the two parts of the casing Vand gain access to the motor and compressor whichV are hermetically sealed within the casing. Inasmuch as in the unit 32 the weld metal which connects the outwardly extending flanges of; the two parts of .the casing faces radiallxl outwardly, Y,such metal can be most conveniently removed `by a grinding wheel which turns about an axis perpendicular to the plane including the weld bead so that the periphery of said wheellies in a horizontal plane.

in Figs. ll-l2. This casing consists of two parts, to wit: a deep lower cup 6G and an lupper cover 62 having a retroverted upwardly extending flange 63 received in the mouth of the cup. The rims of said flange and cup are substantially co-planar and define an upwardly facing parting seam which is closed by a bead 64 of weld deposited metal that likewise faces upwardly. Hence the metal of this bead can best be removed by a grinding wheel the periphery of which lies in a vertical plane.

It shortly will be seen that the machine 20 is suiof units.

In describing said machine I have arbitrarily consid- Yered the same tirst as setup to handle the unit 32, the

grinding wheel accordingly having its periphery located in a horizontal plane and turning about a vertical axis. f

I subsequently, will describe the set-up for opening the casing 5S of the other type of sealed unit.

The machine '20 includes a grinding ,head 66 consisting of a grinding wheel 68, a grinding motor 70, and an adjustable motor support 72.

The grinding wheel is conventional, simply consisting of a circula-rdisc of abrasive material, such for example as oarborundum, and has a central opening to receive the drive shaft 73 of the grinding motor. The wheel is secured to the shaft, as by, a nut screwed on the `Said rack meshes with a pinion' 86 (see Fig. Il) fixed to a shaft 88 journalled in a truck 90 to rotate about .a horizontal axis. The shaft 82 and'rack 84 Vare slidable in a through opening 92 extending vertically through the truck 99 and including an upper portion having spaced vertical walls 94 (see Fig. 3). AV horizontal clamp shaft v96 has, a threaded end screwed into :a tapped bore in one of the walls 94 and an Unthreaded section freely rotatable in an opening in the other wall 94. Adjacent the threaded section said shaft carries a collar 98 from which a handle 101B radially extends. When the threaded section of the clamp shaft is backed partially out of its Y tapped bore the walls 94 will spring apart sufficiently to provide free passage for the vertical shaft 82 and the rack tid. Howeverwhen the clamp shaft is turned in theV opposite direction the walls V94 will be `squeezed together to clamp said shaft 82 in any selected position to v which it has Vbeen. set by manipulating the handle102 on the adjusting shaft 88. It will be appreciated that in this fashion l am quickly and simply able to adjust the horizontal level of the motor casing. Y'

Wheels 164 are provided lat the corners of theV trucli`90. 'Said wheels ride on coplanar horizontal '.anges 106 forming part of the parallel spans`28 and therebyV guiding the truck for level movement ,in a horizontal plane. Attached Vto the truck as by a shackle IGS (Fig. 4) is an elongatedV iiexible member such as a rope .or wire V11i) which turnsgabout a horizontal rotatable idler sheave V112 ward .the casing Vin Va horizontal plane.

` Another common type of sealed unit casing Y'.58 is shown 75 Mounted atV the .lower end of the shaft 82 is a downwardly facing cradle 116 including parallel vertical side arms 118. Horizontal openings'lZi) (Fig. 6V) in hori assauts zontal alignment with one another extend through the arms 118 near their lower ends to receive bushings 122. Iournalled in each bushing is a tube 124 which projects inwardly of the cradle and terminates in a T-shaped head 126. The heads are axially bored and are in registry so yas slideably to receive parallel motor-balancing rods 128. At their opposite ends said rods are connected to :space plates 1138, 132 which are rmly secured, as by screws or bolts to the motor casing 76.

The foregoing arrangement permits the motor to experience two adjustments over and above the change in vertical position brought about by varying the location of the height adjustment shaft 82. These two additional adjustments are rst: a rotatable adjustment of the motor casing with respect to the cradle about the aligned horizontal axes of rotation of the `tubes 124 and, second: `an axial yadjustment of the motor, this latter being accomplished by sliding the rods 128 within the T-shaped heads 126.

Suitable means is included selectively to lock the motor in vany xed position with respect to the two adjustments just described More particularly I locate a split ring 134 (Figs. 6 and 9) on the inner surface of one of the cradle arms 11S. When the ring is unstressed the central opening thereof passes the associated tube 124 and permits free rotation thereof. A pair of screws 136 passing through the ring anchors it to the cradle arm. In order to enable the ring to be constricted on the tube 124 a tapped opening 138 extends away from one side of the slit and a clear opening 148 in registry with the tapped opening extends away from the other side of the split. A short rod has a threaded end screwed into the opening 138 and its shank located in the clear opening 140. ri`he enlarged head 144 of the rod bears against the outer surface of the ring. Thus when the rod is turned, by means of a handle 146, it either will squeeze the tube 124 Iso as to hold the motor casing in Ia pre-set angular orientation with respect to the cradle or will free the tube for rotation to any desired position. l A pair of long set screws 148 (Fig. 6) are threaded through the tapped bores in the tubes 124, said set screws projecting from the tubes and carrying control knobs 150. The inner tips of said screws are adapted to bear against the motor-balancing rods 128. Thus the motor casing can be locked in any selected axial position with respect to the heads 126.

The machine 28 further includes a grinder guard and feeler 152. The guard constitutes a narrow semicylindrical hollow hood 154 carried by a cylindrical sleeve 156 (Fig. 6) that is mounted to turn on the motor casing extension 78. Said sleeve is tapped to receive the threaded end of a locking key 158 (Fig. 7), the tip of which rides in the groove 80 to allow the hood 154 to turn about the grinding wheel and permitted to be locked in any desired position.

The sleeve 156 carries a block 160 (Figs. 1 and 7) provided with a straight cylindrical passageway 162 in which a feeler rod 164 is slidably and rotatably supported. A set screw 166 screwed into the block 160 holds the feeler rod in any given position. Said feeler rod has an end terminating in a feeler body 168 (Figs. 1, 7 and which is provided a through axial passageway 170 at right angles to the longitudinal axis of the feeler rod. The body 168 rotatably carries a feeler holder 172 having an axially located cylindrical boss 174 received in a matching axial well in the body 168. The holder 172 is formed with a through cross bore 176 that passes a feeler linger 178. Said nger is axially shiftable in the bore 176 and is locked in any desired position by a set screw 188. A long bolt 182 extends through the passageway 178 and engages a tapped bore in the holder 172 at the bottom of the well.

It will be appreciated that the feeler finger 178 is capable of experiencing several adjustments. One adjustment is obtained by varying the angular position of the sleeve 156 on the extension 78. Another is obtained by rotating the feeler rod 164. Still another is obtained by axially shifting the feeler rod 164. A fourth adjustment is obtained by rotating the holder 172 with respect to the body 16S. The fifth adjustment is obtained by axially shifting the feeler nger 178. These adjustments are employed for various set-ups of the machine 20, two of which now will be described.

In Fig. 1 I have illustrated the machine arranged to grind oif an outwardly facing welded head 52 the plane of which is substantially horizontal.

The unit 32 is, as noted before, placed on the metal sleeve 58 with the plane of the head substantially horizontal and the center of gravity of the unit located substantially in line with the vertical axis of rotation of the work table. The hold down pin 4l) clamps the unit in place while permitting it to turn with the work table.

The handle 146 is turned to permit the motor casing to be turned in the cradle until the axis of rotation of the motor is vertical so that the plane of the grinding wheel 68 is horizontal. The handle 160 is loosened and the handle 102 turned to locate the grinding wheel in the horizontal plane of the bead 52. The key 158 is loosened and the hood 154 turned so that its open side faces the sealed unit. This will locate the block with its passageway 162 pointed horizontally toward the sealed unit 32. The screw 182 is loosened and the holder 172 turned to bring the finger 178 into the horizontal plane of the rod 164. In may be mentioned that, as is best seen in Fig. 7, the offset eected by the body 168 and the holder 172 is equal to the radial distance between the passageway 162 and the drive shaft 73 of the motor whereby the finger 178 lies in the same plane as the rotary axis of the motor. The set screw is loosened and the tip of the iinger 178 set to be located at such a radial distance from the axis of the grinding wheel that said tip will touch the sealed unit casing when the grinding wheel reaches the base of the weld bead` All the necessary adjustments have now been made, it being understood that the various screws, clamps, etc. that were loosened subsequently were tightened. The cradle thereupon is pulled away from the sealed unit, using the handle 184 to facilitate manipulation. The grinding motor and work table motor are actuated and the handle 184 then released thereby allowing the grinding wheel to engage the weld bead said wheel being biased in that direction by the weight 114. Thereupon the operator can work away from the machine and the machine will continue to move until the wheel seam is open. The limit to which the grinding wheel will penetrate the bead and flanges secured to one another by the bead is determined by the feeler nger 178. As soon as the finger touches the upper part 56 ofthe casing, although both motors still are operating, the grinding wheel will stop removing metal. It will be appreciated since the table is turning some parts of the bead may be removed to the desired depth before other parts but this will be remedied as the table continues to turn so that the other bead parts eventually will be ground away. It also will be seen that if the bead 52 is of non-circular contour or is disposed eccentrically with respect to the axis of rotation of the work table, grindinfy nevertheless will proceed without difficulty since the truck 90 permits the grinding wheel to be moved outwardly and by the periphery of the bead and to return as under the influence of the weight 114. In other words the foregoing construction permits a tloating shiftable movement of the wheel toward and away from the bead in a horizontal direction.

In Figs. 11 and l2 I have illustrated a second set-up of the machine which is suitable for removing an upwardly facing weld bead 64, my machine as so arranged showing a greater degree of versatility than when set-up to remove an outwardly facing bead. To secure the setansa-01s 11p sl'nownin` these gures vthe handle 146 is loosened to permit the motorcasing to kturn freely about the registered'axes ofthe tubes 124. The knobs i5@ are loosened and the rods 128 slid in the heads 126 to place the motor in such ia position that the `center of gravity of the combined motor, motor support, grinding whee grinding hoodandall parts carried thereof yis located in the vertical plane includes the registered axes ofthe tubes 124. Th

knobs 150 thereupon are locked. The key 358 isV loosened and the hood 154 manipulated to locate it above the Ygrinding wheel so that the grinding wheel will project downwardly therefrom and the passageway 162 will be pointed downwardly. The screw 82 is loosened and helder $.72 turned to locate the eeler iinger 17S substantially at right angles to Athe rod 164. The set screw 1166 is loosened and the rod 164 slid out a sufficient distance to locate the 4tip of the feeler nger below the grinding Wheel 1(Fig.,12).` The set screw'll,x is loosened and thetip of the feeler .linger located to ride on the side of the unit when the grinding wheel engages the weld joint. All said screws, hanches, locks, etc., except the handle 14o are tightened. The height of the cradle is set so that with the motor substantially horizontal the periphery of the grinding Wheel is at the top of the bead 64.

The cradle is manipulated to a point such that the tip ofthe feeler finger engages the side surfaces of the lower cup 69 of the sealed unit 58. The grinding wheel is held just out of contact with the beaded and the grinding motor and the table motor are energized. The operator releases his hold on the cradle. The weight 114 thereupon will urge the grinding motor toward the-sealed unit casing. However, only the tip of the eeler linger initially will touch the casing and this will create a torque that Will tilt the grinding wheel and grinding motor as a unit in Va direction such that the grinding wheel will'move downwardly into engagement with the weld bead to be removed. This pressure will maintain the grinding wheel in contact with the bead as the sealed unit turns with the work table.

Any horizontal irregularity or eccentricity of the bead f will cause the grinding motorto move horizontally or away from the axis of rotation of the work table moving either against or under the influence of the weight 114. Any vertical irregularity for eccentricity of the bead will be 'Y compensated for in grinding since the wheel is free to floatingly shift up or down by rotation of the motor casing about the registry horizontal axes of the tubes 7&4, the

Wheel being biased downwardly by the tilting torque engendered by the weight H4.

With the foregoing arrangement it is 4occasionally neci above invention, and as various changes might be made in the embodiments above set forth, it is to be understood that all matter herein set yforth or shown in the accompanying-drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, l claim as new and desire to secure by United States Letters Patent:

l. In a grinder for opening a unit having a casing including atleast two parts joined by an endless welded joint, a grinding head and a work holder, said work holder comprising a table, Vmeans to secure a unit to the table, means to mount said table for rotation about an axis and to turn the table about said axis, said grindingV head including a lgrinding wheel, power actuated means for rotating said wheel about an axis, means supporting GOY Ward and away from the unit in plural planes at the same time, said planes beingat an means biasing the wheel against the welded joint Afor applying a yielding operative pressure against said joint.

2Q In a grinderfor opening a y unit'having a casing including at least two parts joined. by an endless Vwelded joint, a .grinding head and 1a work holder, said work holder comprising a table, means to secure a /unit to the table, means to mount said table for rotation V.about an axis and to turn the table about said axis, said grinding head including a grinding wheel, power actuated means for rotating said wheel about an axis, means supportingV and guiding the Wheel for shiftable floatingV movement toward `and away from theV unit in plural planes at the same time, said planes being atan angle to one another,

and means biasing the wheel against the welded joint for applying a yielding operative pressure against said joint whereby to permit the wheel automatically to VJfollow the joint which deviates from planarity to circularity.

3. In a grinder for opening ay unit having a casing including at least two parts joined by an endless welded joint, a grinding head and a work holder, said work holder comprising a table, means to secure a unit to the table, means to mount said table for rotation about an axis and to turn the table about said axis, said grinding head including a grinding wheel, power actuated means for rotating said wheel about an axis, means supporting and guiding the wheel for shiitable oating movement toward and away from the unit in plural planes at VVthe same time, said planes being at a rightY angle to one another, and means biasing the wheel against the welded joint for applying a yielding operative pressure against said joint whereby to permit the wheel automatically to follow the joint which deviates from planarity to circularity.

4. In a grindery for opening a unit having a casing in- Y cluding at least two parts joined by an endless welded joint, a grinding head and a Work holder, said work holder comprising a table, means to secure a unit to the table, means to mount said table for rotation about an axis and to turn the table about said axis, said grinding head including a Vgrinding wheel, power actuated means for rotating said wheel about an axis, means to adjust the relative position of the table and wheel to match the height of the Wheel to the height of the Welded joint, means supporting and guiding. the wheel for shiftable oating Ymovement toward and away from the unit in plural planes at the same time, said planes being at an angle to one another, and means biasing the wheel against the welded joint for applying a yielding operative pressure against said joint whereby to permit the wheel Vautomatically to follow the joint which deviates from planarity to circularity. Y Y n j 5. In a grinder for opening a unit having a casing includingV at least two parts joined Vby an endless welded f` joint, a grinding head and a work holder, said work holder.l comprising a table, means to secure .a unit to the table, means tomount said table for rotationk about an axis and to turn the table about said axis, said grinding head including a grinding wheel, power-.actuated means for rotating said wheel about an axis, a horizontal track, a truck riding on said track, means :biasing said truck in a direction toward the Work table, and means supporting the wheel from the truck, whereby the wheel is arranged to apply a yielding operative pressure against-the welded joint.`

6. in a grinder for opening a unit havinga casing including at least two parts joined by an endless welded joint, a grinding head and a `Work holder, said work holder comprising a table, means to secure a unit to the table, meansY to Vmount said table for rotation about an axis and to turn the table about said axis, said grinding head .including .a` grinding wheel, power actuated means 'for rotating said wheel about an amsrahorizontal track, a ytrucksriding on said track, means biasingv said truck in a direction toward the -work table, and vertically adjustangle to one another, .and-

able means supporting the wheel from the truck, whereby the wheel is arranged to apply a yielding operative pressure against the welded joint.

7. In a grinder for opening a unit having a casing including at least two parts joined by an endless welded joint, a grinding head and a work holder, said work holder comprising a table, means to secure a unit to the table, means to mount said table for rotation about an axis and to turn the table about said axis, said grinding head including a grinding wheel, power actuated means for rotating said wheel about an axis, a horizontal track, a truck riding on said track, means biasing said truck in a direction toward the work table, and vertically adjustable means supporting the wheel from the truck, said last-named means including means permitting rotation of the axis of rotation or" the wheel about a horizontal axis, whereby the wheel is arranged to apply a yielding operative pressure against the Welded joint.

8. In a grinder for opening a unit having a casing including at least two parts joined by an endless welded joint, a grinding head and a work holder, said work holder comprising a table, means to secure a unit to the table, means to mount said table for rotation about an axis and to turn the table about said axis, said grinding head including a grinding wheel, power actuated means for rotating said wheel about an axis, a horizontal track, a truck riding on said track, means biasing said truck in a direction toward the work table, and vertically ad-.

justable means supporting the wheel from the truck, said last-named means including means selectively permitting rotation of the axis of rotation of the wheel about a horizontal axis, whereby the Wheel is arranged to apply a yielding operative pressure against the Welded joint.

9. in a grinder for opening a unit having a casing including at least two parts joined by an endless welded joint, a grinding head and a work holder, said work holder comprising a table, means to secure a unit to the table, means to mount said table for rotation about an axis and to turn the table about said axis, said grinding head including a grinding wheel, power actuated means for rotating said wheel about an axis, a horizontal track, a truck riding on said track, means biasing said truck in a direction toward the work table, a member, means mounting the member on the truck for vertical movement relative thereto, means mounting the wheel on the member for relative rotation of the axis of rotation of the wheel about a horizontal axis of the wheel, whereby the wheel is arranged to apply a yielding operative pressure against the welded joint.

10. A grinder as set forth in claim 9, wherein means is included selectively to prevent relative rotation between the member and the axis of rotation of the wheel.

11. In a grinder for opening a unit having a casing including at least two parts joined by an endless welded joint, a grinding head and a work holder, said work holder comprising a table, means to secure a unit to the table, means to mount said table for rotation about an axis and to turn the table about said axis, said grinding head including a grinding wheel, power actuated means for rotating said wheel about an axis, means supporting and guiding the wheel for shiftable floating movement toward and away from the unit, means biasing the wheel against the Welded joint for applying a yielding operative pressure against said joint, and means carried by said supporting means for engaging the casing when the grinding wheel has entered into the welded joint a predetermined distance.

12. In a grinder for opening a unit having a casing including at least two parts joined by an endless welded joint, a grinding head and a Work holder, said work holder comprising a table, means to secure a unit to the table, means to mount said table for rotation about an axis and to turn the table about said axis, said grinding head including a grinding wheel, power actuated means for rotating said wheel about an axis, means supporting and guiding the wheel for shiftable floating movement toward and away from the unit, means biasing the wheel against the welded joint for applying a yielding operative pressure against said joint, and adjustable feeler means carried by said supporting means for engaging the casing when the grinding wheel has entered into the Welded joint a predetermined distance.

13. In a grinder for opening a unit having a casing including at least two parts joined by an endless welded joint, a grinding head and a work holder, said work holder comprising a table, means to secure a unit to the table, means to mount said table for rotation about an axis and to turn the table about said axis, said grinding head including a grinding wheel, a motor for rotating said wheel about an axis, a cradle, said motor being located in said cradle, means mounting said motor in said cradle for rotation about an axis perpendicular to the motor axis, means for selectively locking said motor to said cradle, means supporting and guiding the cradle for shiftable lloating movement toward and away from the unit, and means biasing the cradle toward the unit.

14. In a grinder for opening a unit having a casing including at least two parts joined by an endless welded joint, a grinding head and a work holder, said work holder comprising a table, means to secure a unit to the table, means to mount said table for rotation about an axis and to turn the table about said axis, said grinding head including a grinding wheel, a motor for rotating said wheel about an axis, a truck, rails guiding the truck in a direction toward and away from the unit perpendicular to the axis of rotation of the table, a cradle, vertically adjustable means supporting the cradle from the truck, means supporting the motor from the cradle for rotation about a horizontal axis, means selectively preventing rotation of the motor relative to the cradle, and means biasing the truck toward the unit.

15. In a grinder wherein a work piece is turned about a horizontal axis and wherein a top portion of the work piece adjacent its circumference is to be ground: that improvement comprising a grinding wheel, power actuated means for rotating said wheel about an axis, means supporting and guiding said wheel for shiftable oating movement toward and away from the work piece in one plane, means supporting and guiding the wheel for shiftable iloating movement toward and away from the work piece in another plane at the same time that the wheel is supported and guided for shiftable movement toward and away vfrom the work piece in the rst-named plane, and means biasing the wheel in said planes against the work piece for applying a yielding operative pressure against said piece.

16. In a grinder wherein a work piece is turned about a horizontal axis and wherein a top portion of the work piece adjacent its circumference is to be ground: that improvement comprising a grinding wheel, power actuated means for rotating said wheel about an axis, means supporting and guiding the wheel for shiftable oating movement toward and away from the side of the work piece,

means biasing the wheel toward the work piece from the side, a feeler movable bodily with the power actuated means and supported to engage the work piece from the side, and means supporting the power actuated means for rotation about an axis transverse to the direction of movement of the wheel under the inuence of the supporting means whereby the wheel also is supported and guided for shiftable iloating movement toward and away from the top of the work piece and yieldably biased against said top of the work piece.

References Cited in the le of this patent UNITED STATES PATENTS 2,775,852 LoWitz Ian. 11, 1957