US3793695A

US3793695A - Device for automatically loading an oil ring spacer-expander into the oil ring groove of a piston

Info

Publication number: US3793695A
Application number: US00284656A
Authority: US
Inventors: R Carter; J Clifford
Original assignee: Sealed Power Corp
Current assignee: Sealed Power Technologies LP; Kodiak Partners Corp
Priority date: 1972-08-29
Filing date: 1972-08-29
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26

Abstract

A device for automatically loading an oil ring spacer-expander into the oil ring groove of a piston. The device has an expandable mandrel over which is telescoped a fiberboard tube upon which a quantity of spacer-expanders are stacked. The mandrel is expanded by a cam arrangement so that the inside dimension of the shoe surfaces of the mandrel are slightly larger than the largest land diameter of the piston. Upon inserting a piston into the open end of the expanded mandrel, the top of the piston acts through a push rod to open an air valve, pressurizing a cylinder which causes a pawl to engage a rack and move the cylinder and a pusher ahead one rack pitch or ring width. The pusher engages the rear spacer-expander of the stack of spacerexpanders and advances the stack one ring width, the forward spacer-expander on the stack being pushed from the tube into the oil ring groove. Upon removal of the piston the air valve is closed, de-pressurizing the cylinder, causing the pawl to advance one rack pitch, and the cycle will be repeated upon the insertion of another piston into the expanded mandrel. When the last ring on the tube has been loaded, the mandrel is collapsed, the empty tube removed, the cylinder, pawl and pusher assembly moved to starting position and a new fiberboard tube with a stack of spacer-expanders is telescoped over the mandrel and the device is again ready to load spacer-expanders on successive pistons.

Description

[ Feb. 26, 1974 nited States Patent [1 1 Carter et al.

[54] DEVICE FOR AUTOMATICALLY LOADING vice has an expandable mandrel over which is tele- AN OIL RING SPACER-EXPANDER INTO THE OIL RING GROOVE OF A PISTON scoped a fiberboard tube upon which a quantity of spacer-expanders are stacked. The mandrel is expanded by a cam arrangement so that the inside di- [75] Inventors: Carter Muskegon; Jack mension of the shoe surfaces of the mandrel are gl g North Muskegon both slightly larger than the largest land diameter of the pis- 0 IC ton. Upon inserting a piston into the open end of the [73] Assi nee; Seal d Po C r ti n, expanded mandrel, the top of the piston acts through Muskegon, Mich.

a push rod to open an air valve, pressurizing a cylinder which causes a pawl to engage a rack and move the cylinder and a pusher ahead one rack pitch or ring [22] Filed:

[21] Appl. No.: 284,656 width. The pusher engages the rear spacer-expander of the stack of spacer-expanders and advances the stack one ring width, the forward spacer-expander on the stack being pushed from the tube into the oil ring groove. Upon removal of the piston the air valve is aw 2 00 5 W 0. Q R2 13 1 an Rm 9/2 272 rm m2R m B l 2 4 9 T Wwh C r a u n 9 s I. h f C l 0 WM umm i. l l 2 00 5 5 5 closed, de-pressurizing the cylinder, causing the pawl to advance one rack pitch, and the cycle will be re- References Cited UNITED STATES PATENTS peated upon the insertion of another piston into the expanded mandrel. When the last ring on the tube has 2,792,625 Hoffman 29/2ll R been loaded, the mandrel is collapsed, the empty tube removed, the cylinder, pawl and pusher assembly moved to starting position and a new fiberboard tube Primary Examiner-Thomas l-l. Eager Attorney, Agent, or Firm-Barnes, Kisselle, Raisch & with a stack of spacer-expanders is telescoped over Choate the mandrel and the device is again ready to load spacer-expanders on successive pistons.

[57] ABSTRACT A device for automatically loading an oil ring spacerexpander into the oil ring groove of a piston. The de- 23 Claims, 17 Drawing Figures PATENTEDFEBZS I974 SHEET 1 OF 6 PATENTEB FEBZ B1974 SHEET 3 BF 6 lrw PAIENTEDFEBZBW v 3,793,695

SHEET 5 [IF 6 PM'ENTEB FEB 26 1974 SHEET 8 0F 6 DEVICE FOR AUTOMATICALLY LOADING AN OIL RING SPACER-EXPANDIER DITO THE OIL RING GROOVE OF A PISTON This invention relates to a device for automatically loading oil ring spacer-expanders into the oil ring grooves of pistons.

It is an object of this invention to provide a device for automatically loading oil ring spacer-expanders into the oil ring grooves of pistons such as those commonly used in internal combustion engines, which is more economical and expeditious than hand loading of thesespacer-expanders as now generally practiced.

In hand loading the spacer-expander into the oil ring groove of a piston, the operator has to remove the spacer-expander from the cardboard or fiber tube on which the spacer-expanders are stacked, expand the spacerexpander over the piston head, and insert it into the oil ring groove. Frequently the operator over expands the spacer-expander and distorts the same so that the distortion may lead to premature failure or malfunctioning of the spacer-expander and subsequent malfunctioning of the engine.

In hand loading a spacer-expander into the oil ring groove of a piston, the operator sometimes does so with the gap ends of the spacer-expander overlapped. An overlapped spacer-expander is non-functional and causes malfunctioning of the engine. It is a further object of the invention to provide a machine for loading the spacer-expander into the oil ring groove of a piston so that the gap ends of the spacer-expander will properly abut and not overlap.

Other objects and features of the invention will become apparent from the following description and drawings in which:

FIG. I is a side elevation partly in section showing the drawing for loading an oil ring spacer-expander into the oil ring groove of a piston with the spacer-expander pusher in start position.

FIG. 2 is a detail of-the pneumatic cylinder, pawl and rack device for advancing the pusher.

FIG. 3 is a fragmentary side view of the loading device just after a spacer-expander has been loaded into the oil ring groove of a piston.

FIG. 4 is an enlarged detail showing the movement of the spacer-expander from the end of the fiber tube on the mandrel into the oil ring groove of the piston.

FIG. 5 is a detail of a conventional oil ring spacerexpander which, by way of example, can be loaded into the oil ring groove of a piston by the subject device.

FIG. 6 is a fragmentary detail showing the fiberboard tube with its stack of spacer-expanders expanded by the shoes of the mandrel.

FIG. 7 is a plan view partly in section showing the spacer-expander pusher in an advanced position.

FIG. 8 is a section taken along the line 8-8 of FIG. 7.

FIG. 9 is a section taken along the line 9--9 of FIG.

FIG. 10 is a front view of the device showing the mandrel in position to receive a fiber tube on which spacer-expanders are stacked.

FIG. 11 is a side elevation of the fiber spacerexpander loading tube showing the diameter of the tube as it is telescoped on to the mandrel in full lines and showing in dotted lines the diameter of the tube after being expanded by the mandrel.

FIG. 12 is a vertical section through the device at the fiber tube holding shoe assembly along the line l2-12 of FIG. 1.

FIG. 13 is a longitudinal section through the device showing the cam and expander bar arrangement for expanding the mandrel.

FIG. 14 is a section along the line 14-44 of FIG. 13 showing the mandrel expanded.

FIG. 15 is a sectional view similar to FIG. 14 but showing the mandrel contracted. 1

FIG. 16 is a section along the line 16-16 of FIG. 13 showing one of the switch and spring arrangements for the mandrel expanding bars.

FIG. 17 is a detail of one of the mandrel shoes, its expander bar, and the guide for the expander bar.

In manufacturing oil ring spacer'expanders, the spacer-expanders 1 are stacked on a cardboard or fiber tube 2 which is split longitudinally as at 3 so that it is expandable. One end of the 'tube is provided with a tongue 4 which is slipped into a slit 5 in the other end of the tube. This arrangement permits the tube and the spacer-expanders mounted thereon to be expanded without the tongue 4 sliding out of the slit 5, FIG. 11.

The device for moving the spacer-expanders one at a time from the tube 2 and assembling them in the oil ring grooves of the pistons comprises a base plate 6, a valve mounting plate 7 affixed thereto, and a mandrel mounting plate 8 secured thereto by bolts 9.

The mandrel for telescopically receiving a tube 2 upon which the spacer-expanders are stacked comprises an expander frame generally designated 10. The frame consists of a pair of spaced

end rings

12 and 13, a center ring 14 and four radial guides 15 circumferentially positioned at intervals. The expander frame is fixed on the mounting plate 8 by securing end ring 12 to the mounting plate 8 by any suitable means such as the screws 24. Each guide consists of a pair of spaced plates 16 welded or otherwise affixed at their ends to the

end rings

12, 12 and at their centers to the center ring 14. Each of the four guides receives a radially slidable expander bar 17. The expander bars are yieldably held in contracted position by two sets of tension springs 20. Each set of tension springs comprises an array of four tension springs 20 connected at their outer ends to swivels 21 mounted in openings provided therefor in the expander bars (FIG. 15). Each expander bar is provided with a pair of spaced recesses 18 along its inner edge in which are mounted cam followers in the form of roller 19.

A tubular center bar 22 is journaled in openings located centrally of the

guide rings

12, 13 and 14. A pair of star shaped cams 23 are fixed on the outside of the bar 22 between the rollers 19 at the inner ends of the expander bars 17, as shown in FIGS. 14 and 15. Tension springs 20 draw the expander bars radially inwardly and hold the rollers 19 yieldably against the outer faces or contours of the cams 23.

An arcuate shoe 25 is secured to the outer face of each expander bar 17 in any suitable manner as by the screws 26, FIG. 13. A lever or handle 27 is affixed to the end of expander bar 22 for turning the expander bar and cams to expand and collapse the mandrel. Four holding shoe assemblies 28 are mounted on the mounting plate 8 on the mandrel side of said plate. Each holding shoe assembly comprises a housing 29 secured to the mounting plate 8 for housing a plunger 30, a compression spring 31 and a show 32 on the inner end of the plunger 30. The springs 31 act through plungers to urge the shoes 32 radially inwardly for the purpose of clamping the end of the fiber tube between the expanded mandrel shoes 25 and the holding shoes 32 for holding the fiberboard tube so that it cannot move axially or to the right, FIG. 1, while the device is being operated to assemble spacer-expanders on successive pistons.

The mechanism for moving spacer-expanders one at a time off the right hand end of the fiber tube consists of a pusher plate 33 fixed at its lower end on a slide 34 slidably mounted on a rack bar 35 fixedly mounted centrally and lengthwise of the base plate 6. The pusher plate 33 is provided with a circular opening 36 surrounding the mandrel. The diameter of the opening 36 is less than the outer diameter of the spacerexpanders when the mandrel is expanded preparatory to loading the spacer-expanders one at a time on successive pistons. The pusher plate advances step by step one rack pitch which is equivalent to the width of one spacer-expander.

For advancing the pusher plate 33 step by step there is provided an air cylinder 37 which is fixed on the slide 34. Inside the cylinder is a piston 38 on the end of a piston rod 39, FIG. 8. The outer end of rod 39 is provided with a bracket 40 provided with a bifurcated lower end upon which is pivotally mounted pawl 41 by means of pin 42. The pawl can be released from the rack 35 by a release lever 43 pivoted as at 44 on Slide 34. A tension spring 45 acting between shoulder screw 46 on pusher plate 33 and the right hand end of the release lever 43 urges the lever in a counterclockwise direction as viewed in FIG. 3. The lever 43 passes through a vertically elongated window 47 in pawl 41 such that depression of the right hand end of lever 43 (FIG. 1) causes the pawl 41 to be raised clear of the rack 35 so that the slide 34 may be moved to the left. During that portion of the advancement cycle where the piston 38 (FIG. 8) is moving to the right to advance the pawl 41 to the next tooth on the rack 35 the elongated window 47 in the pawl 41 allows the pawl to raise over the tooth without interaction with lever 43. The weight of the pawl is such that gravity alone is sufficient to insure engagement of the pawl with the next tooth on the rack. By pushing downwardly on the outer end of lever 43 (FIG. 2), the pawl can be raised and disengaged from the rack. A compression spring 48 is mounted within cylinder 37 between the piston 38 and the left hand end of cylinder 37 urges the piston to the right as viewed in FIG. 8.

Compressed air under pressure is admitted from source of compressed air (not shown) to air line 49 to three-way valve 50 and thence through air line 51 and coupling 52 through the closed end of cylinder 37 to the right of piston 38. Slide 34 is provided at its left hand end with a vertical projection 73 in which is mounted an adjustable set screw 53, FIGS. 2 and 8. The inner end 54 of adjustable screw 53 coacts with the left hand end 55 of piston rod 39 to limit the right hand or forward travel or advance of the cylinder 37 and pusher slide 33. When cylinder 37 is exhausted, spring 48 advances the pawl 41 one tooth or rack pitch along the rack. The advance of the cylinder and pusher slide, each time compressed air is admitted into the cylinder, can be limited to the pitch of the rack which is equivalent to the width of one spacer-expander by adjusting stop screw 52 with respect to end 55 of the piston rod.

Valve 50 interposed in the air line is a conventional three-way valve actuated by a lever 56 provided with a roller 57 at its outer end which engages a collar 58 fixed on a push rod 59. Valve lever is conventionally spring biased to vertical position as shown in FIG. 1 which closes off compressed air line 49 and opens line 51 to exhaust. Rod 59 is slidably supported at its left hand end in an opening 60 in plate 61 mounted on the housing of valve 50, FIG. 7. Pusher rod 59 passes through expander bar or tube 22 and is slidably supported at its right hand end in end ring 13 and adapter collar 80 secured on outer end of tube 22. Adapter 80 is provided with a plurality of adjustable stops 61 which are contacted by the inner face of the piston to which a spacer-expander is being applied, FIG. 3. A collar or ring fixed on the left hand end of tube 22 (FIG. 13) coacts with collar to retain tube 22 rotatively within expander frame 10.

By way of example, spacer-expander 1 can be of the parted type shown in the Olson U.S. Pat. No. 2,789,872 but the device is suitable for assembling any parted spring type spacer-expander or piston ring in the ring groove of a piston such as the conventional internal combustion engine piston. A quantity of oil ring spacerexpanders are stacked axially on the fiberboard tube at the point of manufacture. At the point of assembly the fiber tube with spacer-expanders stacked thereon is fitted axially over or telescoped on to the collapsed mandrel of the loading device with the mandrel contracted (FIG. 15, also dotted line showing, FIG. 1).

It will be noted in FIG. 11 that the fiber tube 2 extends somewhat beyond the left hand end of the stack of spacer-expanders as at 65. When the tube loaded with spacer-expanders is mounted on the mandrel, the left hand end 65, free of rings, abuts against the mounting plate 8 so that the free end 65 is positioned between the holding shoes 32 and the mandrel shoes 25. The mandrel is now expanded by swinging lever 27 from'the vertical position (FIG. 10), full lines, clockwise to the horizontal position, dotted line showing. This movement of the lever from the vertical to the horizontal position rotates expander bar 22 and cams 23 from the contracted position of the mandrel, FIG. 15, to the expanded position of the mandrel, FIG. 14. The cam followers 19 in riding up the faces of the cam impart an outward linear motion to the expander bars 17 to thereby move the mandrel shoes 25 radially outwardly. This expanding of the mandrel from the contracted position, FIG. 15, full line showing FIG. 10, to the expanded position, FIG. 14, causes the clear end 65 of the fiber tube 2 to be clamped between the mandrel shoes 25 and the holding shoes 32, as shown in FIG. 12, full lines, so that the tube cannot move axially during operation.

Before the fiber tube loaded with spacer-expanders is telescoped over the mandrel, the pusher assembly is moved to the left and located as shown in FIG. 1 with the pusher plate 33 against holding shoe assemblies 28 extending from the mounting plate 8. At this time the three-way valve is in exhaust position so there is no compressed air in the cylinder 37, the pawl 41 is interengaged with a tooth of the rack 35, and stops 53 and 55 are positioned one rack pitch or spacer-expander width apart.

When the layer 27 is swung clockwise to expand the mandrel, the inside dimension between the inner surfaces of opposite shoes 25 is slightly larger than the largest diameter of the piston on which the spacerexpander is to be loaded. This allows the piston head to be inserted into the mandrel against adjustable stops -61, FIG. 3, to a depth such that the outer ends of the mandrel shoes 25 are flush with the top side of the oil ring groove 70 of the piston 71 FIGS. 3 and 4. The expansion of the mandrel expands the fiber tube and stack of spacer-expanders so that during pneumatic actuation of the device the pusher engages the left hand end of the stack of spacer-expanders and moves it axi ally along the fiber tube, the free end of which is clamped as above stated. When the mandrel is ex panded by swinging of handle 27 as above described, the outward movement of the expander bars 17 stretches or tensions springs 20 so that on release of the handle the mandrel collapses to its closed diameter because the tension of the springs act through the expander bars 17 and rollers 19 against the face of the cams to rotate them counterclockwise from the expanded position, FIG. 14, to the collapsed position shown in FIG. 15. In any event the handle 27 can always be manually rotated from the dotted line position, FIG. 10, to the full line position to collapse the mandrel to its closed diameter, FIG. 15.

With the device connected to a compressed air source through line 49, the pusher assembly set at its extreme rear position (FIG. 1), a tube of spacerexpanders on the mandrel with the tube clamped by the holding shoes and with no rings behind the pusher plate 33, and the mandrel expanded, a piston 71 is inserted into the open end of the mandrel with the top face of the piston abutting the adjustable stops 61. As the piston is inserted into the mandrel and against stops 61, its top face abuts push rod 59 which is in extended position, FIG. 13, and moves it toward the left to the position shown in FIG. 3. This leftward movement of the push rod acts through collar 58 and

valve lever

56, 57 to open valve 50 so that compressed air is admitted through

lines

51 and 52 into the cylinder 37 to the right of piston 38. Since piston 38 is prevented by engagement of pawl 41 with rack from moving toward the left, the air pressure from line 52 causes the cylinder 37 to move or advance toward the right until stop 53 abuts stop 55 on the left hand end of the piston rod 39. The width of the gap between stops 55 and 54 is such that the forward or rightward movement, FIG. 8, of the cylinder and pusher plate 33 is equivalent to one rack pitch or one ring width thus moving the pusher rightward or forward one ring width to thereby advance the stack one ring width and the forward ring of the stack is pushed from the end of the tube into the piston ring groove 70 as illustrated in FIG. 4. The piston 71 is now withdrawn from the mandrel and thereby permits spring biased

valve lever

56, 57 to move to the right thereby shutting off the compressed air from line 49 and opening the cylinder and

lines

52 and 51 to exhaust and returning rod 59 to start position, FIG. 13. The weight of the cylinder pusher plate and slide 34 is such that they remain in the position to which they were moved as explained above, whereupon spring 48 acting between piston 38 and the left hand end of cylinder 37 expands. As spring 48 expands, it moves piston 38, piston rod 39, and the pawl 41 forward one pitch or tooth to the right on rack 35 and the device is now ready to load a spacer-expander on the next piston.

When the last spacer-expander on the tube has been loaded, the mandrel is collapsed by rotating lever 43 counterclockwise to vertical position (dotted line showing FIG. 12) and the fiber tube removed. The pawl release lever 43 is depressed to release pawl 41 from rack 35 and the pusher slide 34, pusher plate 33, and cylinder assembly is moved to the left or backward to starting position, FIG. 1. The device is now ready for another tube loaded with a stack of spacer-expanders to be installed as described above and the full cycle is repeated.

The forward end of the mandrel from which the rings are loaded one at a time upon consecutive pistons inserted into the mandrel is termed the loading end of the mandrel.

We claim:

1. A device for loading a parted ring into the ring groove of a piston comprising an expandable mandrel adapted to receive an expandable tube upon which a quantity of rings are stacked, means for expanding the mandrel so that the inside diameter of the mandrel is large than the largest land diameter of the piston upon which a ring is to be loaded, means for holding the tube against movement along the mandrel, a pusher adapted to engage the rear end of the stack of rings remote from the loading end of the mandrel, means for advancing the pusher step by step one ring width at a time, means actuated by the piston as it is inserted into the loading end of the expanded mandrel with the upper face of the piston ring groove substantially flush with the loading end of the mandrel whereby the pusher advancing means is activated and the pusher engages the rear ring of the stack of rings and advances the stack one ring width and the forward ring on the stack is pushed from the tube into the ring groove of the inserted piston, and means actuated upon removal of the piston from the loading end of the mandrel to reset the pusher advancing means for repeating its cycle of operation upon insertion of another piston into the expanded mandrel.

2. The combination set forth in claim 1 including stop means adjacent the loading end of the mandrel against which the piston abuts when inserted in the mandrel so that the upper face of the piston ring groove is substantially flush with the loading end of the mandrel.

3. The device set forth in claim 1 wherein the means for expanding the mandrel includes a rotatable shaft within the mandrel and cam means rotatable by the said shaft whereby upon rotating the shaft in one direction the cam means expands the mandrel and upon rotation in the opposite direction the mandrel contracts.

4. The combination set forth in claim 3 wherein the cam means comprises at least one cam fixed on said shaft and at least one slide bar movable radially outwardly by the cam to expand the mandrel when the cam is rotated in one direction and movable radially inwardly when the cam is rotated in the opposite direction to contract the mandrel.

5. The combination set forth on claim 4 wherein the cam has a plurality of cam faces and a radially guided slide bar for each cam face.

6. The combination set forth in claim 5 wherein each slide bar is provided with a fixed guide for guiding the slide bar in its inward and outward movement, and resilient means operatively connected to each slide bar for opposing outward motion thereof by the cam and for returning the slide bar radially inwardly upon the said opposite rotation of the cam.

7. The combination set forth in claim 6 wherein the mandrel includes a plurality of arcuate sections and a slide bar for each section, each section being secured to the outer end of slide bar whereby when the slide bars are moved radially outward by rotation of the cam the sections move radially outwardly to increase the diameter of the mandrel.

8. The device set forth in claim 1 wherein the tube and a stack of rings therein with the rear end of the stack of rings spaced from the rear end of the tube are adapted for mounting on the mandrel with the forward end of the tube substantially flush with the loading end of the mandrel and including a support for the mandrel, and wherein said holding means comprises locking means carried on the support radially outwardly of the mandrel cooperating with the end of the mandrel adjacent the rear end of the tube for gripping the rear end of the tube and holding the tube against movement along the mandrel.

9. The device set forth in claim 8 wherein the means for gripping the rear end of the tube comprises at least one shoe cooperating with the mandrel when expanded to grip the rear end of the tube therebetween, and resilient means for urging the shoe radially inwardly against the rear end of the expanded tube.

10. The device set forth in claim 1 wherein the means for advancing the pusher step by step one ring width at a time includes a rack having a pitch substantially equal to one ring width and a pawl advanceable along the rack one ring width at a time.

11. The device set forth in claim 10 including a compressed fluid actuated piston and cylinder coacting with the pawl and rack for advancing the pusher step by step one ring width at a time.

12. The combination set forth in claim 1 wherein the means for advancing the pusher includes a stationary toothed rack having a rack pitch substantially equal to one ring width, a slide guided by the rack and carrying said .pusher, a reciprocable pawl coacting with said rack and carried by said slide, and means for reciprocating the pawl relative to said pusher, each stroke of the pawl being substantially equal to one ring width whereby as the pawl reciprocates relative to the pusher the pawl travels over the rack teeth and advances the pusher step by step one ring width at a time.

13. The combination set forth in claim 1 wherein the means for advancing the pushercomprises a stationary rack, a slide guided along the rack, the pusher being mounted on said slide, a cylinder carried by the slide, a reciprocating piston in said cylinder, a pivoted pawl connected to said piston, stop means for limiting the stroke of the piston to substantially one ring width whereby when compressed fluid is admitted into the cylinder, the pawl is meshed with the rack and the cylinder coacts with the pawl to advance the pusher one ring width.

14. A device for loading a parted ring into the ring groove of a piston comprising an expandable mandrel adapted to telescopically receive an expandable tube upon which a quantity of rings are stacked in face to face contact, means for expanding the mandrel, tube and stack of rings so that the inside diameter of the mandrel is larger than the largest land diameter of the piston upon which a ring is to be loaded, a pusher adapted to engage the rear end of the stack of rings remote from the loading end of the mandrel, means for advancing the pusher step by step one ring width at a time, means actuated by the piston as it is inserted in the loading end of the expanded mandrel for activating the pusher advancing means whereby the pusher advances the entire stack one ring width and the forward ring of the stack is pushed from the stack into the ring groove of the inserted piston, and means actuated upon removal of the piston from the loading end of the mandrel to reset the pusher advancing means for repeating its cycle of operation upon insertion of another piston into the expanded mandrel.

15. The combination set forth in claim 14 including means for'locking the tube against movement along the expanded mandrel with the forward end of the tube substantially flush with the loading end of the mandrel.

16. The combination set forth in claim 15 including stop means adjacent the loading end of the mandrel against which the piston abuts when inserted in the mandrel so that the upper face of the piston ring groove is substantially flush with the loading end of the mandrel.

17. A device for loading a parted ring into the ring groove of a piston comprising an expandable mandrel adapted to telescopically receive an expandable tube upon which a quantity of rings are stacked, means for expanding the mandrel, tube and stack of rings so that the inside diameter of the mandrel is larger than the largest land diameter of the piston upon which a ring is to be loaded, a pusher adapted to engage the rear end of the stack of rings remote from the loading end of the mandrel, a slide for supporting said pusher, pneumatic means for advancing the pusher step by step one ring width at a time, a source of fluid under pressure for actuating said pneumatic means, a valve for controlling communication between the source of fluid pressure and the pusher advancing means, and stop means adjacent the loading end of the mandrel against which the piston abuts when inserted in the mandrel so that the upper face of the piston ring groove is substantially flush with the loading end of the mandrel, and means actuated by the piston when inserted into the mandrel against the stops for opening said valve to place the source of fluid under pressure in communication with said pneumatic means whereby the pusher is advanced one ring width and the forward ring of the stack is pushed from the stack into the ring groove of the piston.

18. The combination set forth in claim 17 including a stationary rack and the pneumatic means for advancing the pusher step by step includes a support slidable along said rack for supporting said pusher, a cylinder carried by said slidable support, a piston in said cylinder, a pawl carried by said piston adapted to engage said rack, adjustable stop means for limiting the stroke of the piston relative to said cylinder to one ring width whereby when the valve is opened by inserting a piston into the mandrel the fluid under pressure is admitted into the cylinder and the cylinder advances along said rack one ring width, means actuated upon removal of the piston from the loading end of the mandrel to return said valve to its start position whereupon the cylinder is depressurized, and means for advancing the pawl one rack pitch upon depressurizing said cylinder.

19. The combination set forth in claim 18 wherein the means actuated by the piston when inserted into the mandrel comprises a rod extending lengthwise through the mandrel and operatively connected to the valve for opening the same.

20. A device for loading a parted ring into the ring groove of a piston comprising an expandable mandrel, an expandable tube adapted to carry a stack of rings in face to face contact telescopically mounted on said mandrel, means for expanding the mandrel, tube and stack of rings so that the inside diameter of the mandrel is larger than the largest land diameter of the piston upon which a ring is to be loaded, a pusher adapted to engage the rear end of the stack of rings remote from the loading end of the mandrel, a slide for supporting said pusher, pneumatic means for advancing the pusher step by step one ring width at a time, a source of fluid under pressure for actuating said pneumatic means, a valve for controlling communication between the source of fluid pressure and the pusher advancing means, and stop means adjacent the loading end of the mandrel against which the piston abuts when inserted in the mandrel so that the upper face of the piston ring groove is substantially flush with the loading end of the mandrel, and means actuated by the piston when inserted into the mandrel against the stops for opening said valve to place the source of fluid under pressure in communication with said pneumatic means whereby the pusher is' advanced one ring width and the forward ring of the stack is pushed from the stack into the ring groove of the piston.

21. A device for loading a parted ring into the ring groove of a piston comprising an expandable mandrel, an expandable tube adapted to carry a stack of rings in face to face contact telescopically mounted on said mandrel, means for expanding the mandrel and tube so that the inside diameter of the mandrel is larger than the largest land diameter of the piston upon which a ring is to be loaded, means for holding the tube against movement along the mandrel, a pusher adapted to engage the rear end of the stack of rings remote from the loading end of the mandrel, means for advancing the pusher step by step one ring width at a time, means actuated by the piston as it is inserted into the loading end of the expanded mandrel with the upper face of the piston ring groove substantially flush with the loading end of the mandrel whereby the pusher advancing means is activated and the pusher engages the rear ring of the stack of rings and advances the stack one ring width and the forward ring on the stack is pushed from the tube into the ring groove of the inserted piston, and means actuatable upon removal of the piston from the loading end of the mandrel to reset the pusher advancing means for repeating its cycle of operation upon insertion of another piston into the expanded mandrel.

22. The combination set forth in claim 21 including stop means adjacent the loading end of the mandrel against which the piston abuts when inserted in the mandrel so that the upper face of the piston ring groove is substantially flush with the loading end of the mandrel.

23. The combination set forth in claim 22 wherein the means for expanding the mandrel includes a rotatable shaft within the mandrel and cam means rotatable by the said shaft whereby upon rotating the shaft in one direction the cam means expands the mandrel and upon rotation in the opposite direction the mandrel contracts.

PO-ww UNITED STATES PATENT QF ICE";

CERTIFICATE OF CORRECTION Patent No. 3|793'695 Q D ted Februairy 26, 1,974

InVentOI-(S) Ronald E. Carter and Jack Clifford It is certified vthat error appears in the above identified patent and that said Letters Patent are hereby corrected .as shown below:

Column 2, line 12 cancel "switch" and :insett swivel-.

Column 3, line 48: cancel "is".

Column 4, line 1: cancel "52 and inseit't": -53.

Column 6, line 24: cancel "large" and insert larger-.

Column 7, line 12: 4 cancel "therein" insert -thereon--. i

Signed and sealed this 22nd day 'ofOctobei' 1974.

(SEAL) Attest:

McoY M. CIR-SON JR. c. MARSHALL DANN- Attesting Officer Commissioner-0f Patents

Claims

12. The combination set forth in claim 1 wherein the means for advancing the pusher includes a stationary toothed rack having a rack pitch substantially equal to one ring width, a slide guided by the rack and carrying said pusher, a reciprocable pawl coacting with said rack and carried by said slide, and means for reciprocating the pawl relative to said pusher, each stroke of the pawl being substantially equal to one ring width whereby as the pawl reciprocates relative to the pusher the pawl travels over the rack teeth and advances the pusher step by step one ring width at a time.

13. The combination set forth in claim 1 wherein the means for advancing the pusher comprises a stationary rack, a slide guided along the rack, the pusher being mounted on said slide, a cylinder carried by the slide, a reciprocating piston in said cylinder, a pivoted pawl connected to said piston, stop means for limiting the stroke of the piston to substantially one ring width whereby when compressed fluid is admitted into the cylinder, the pawl is meshed with the rack and the cylinder coacts with the pawl to advance the pusher one ring width.

15. The combination set forth in claim 14 including means for locking the tube against movement along the expanded mandrel with the forward end of the tube substantially flush with the loading end of the mandrel.

20. A device for loading a parted ring into the ring groove of a piston comprising an expandable mandrel, an expandable tube adapted to carry a stack of rings in face to face contact telescopically mounted on said mandrel, means for expanding the mandrel, tube and stack of rings so that the inside diameter of the mandrel is larger than the largest land diameter of the piston upon which a ring is to be loaded, a pusher adapted to engage the rear end of the stack of rings remote from the loading end of the mandrel, a slide for supporting said pusher, pneumatic means for advancing the pusher step by step one ring width at a time, a source of fluid under pressure for actuating said pneumatic means, a valve for controlling communication between the source of fluid pressure and the pusher advancing means, and stop means adjacent the loading end of the mandrel against which the piston abuts when inserted in the mandrel so that the upper face of the piston ring groove is substantially flush with the loading end of the mandrel, and means actuated by the piston when inserted into the mandrel against the stops for opening said valve to place the source of fluid under pressure in communication with said pneumatic means whereby the pusher is advanced one ring width and the forward ring of the stack is pushed from the stack into the ring groove of the piston.