US1980288A - Cylinder ridge reamer - Google Patents

Description

Nov. 13, 1934. c. A. OLSON CYLINbER RIDGE H E AMER Filed April 11, 1952 2 Sheets-Sheet 1 I 1 u 5 w n l Patented Nov. 13, 1934 PATENT OFFICE CYLINDER RIDGE REAMER Carl A. Olson, Clarinda, Iowa, assignor to Lisle Corporation, Clarmda, Iowa, a corporation of Iowa Application April 11, 1932, Serial No. 604,481

4 Claims.

The object of this invention is to provide an improved construction for a tool for reaming and dressing the wall of a cylinder and for removing the ledge or projection which is commonly formed near one end of the cylinder of an internal combustion engine on account of the fact that the uppermost piston ring does not ordinarily travel entirely to the end of the cylinder bore.

A further object of the invention is to provide an improved construction for a cylinder ridge reamer having means for causing the operation of the reaming or cutting element to conform to the contour of a portion of the cylinder wall which is not engaged by said element.

Still another object is to provide an improved cylinder ridge reamer having an element adapted to engage and travel on a portion of the cylinder wall during operation of the tool and serving to guide the cutting member in such manner as to cause its cutting operation to conform to the contour of that portion of the wall engaged by said element.

Another and further object of the invention is to provide improved means for supporting a reaming tool in position for operation upon the walls of a cylinder and for causing the cutting operation to be performed during rotary movement of the tool and coincident movement in a direction longitudinally of a cylinder bore.

With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in the specification, and illustrated in the accompanying drawings, in which:-

Figure 1 is a plan view, partly in section, illustrating one form of my improved tool in position for practical use in a cylinder bore.

40 Figure 2 is a side elevation of the tool.

Figure 3 is a vertical section on the line 3-3 of Figure 1, showing the tool in position for use.

Figure 4 is a sectional view similar to a portion of the showing in Figure 3 but illustrating a modified form of guiding means for the cutting element.

Figure 5 is a sectional view showing a piston in its cylinder and illustrating the condition which my improved tool is designed to relieve.

Figure 6'is'a plan view, partly in section, illustrating a modified form of the tool in which a different type of support is employed.

Figure '7 is a vertical section showing the tool of Figure 6 in position for operation in the cylinder.

Figure 8 is a vertical sectional view showing a modified form of a tool which has some of the same general characteristics as the tool illustrated in Figures 6 and '7.

Figure 9 is a sectional elevation showing a further modified form.

Figure 10 is a longitudinal section of a modified form of carrier member having the cutting element formed directly thereon.

Figure 11 is an elevation of a further modified form of carrier member in which the guiding means as well as the cutting element are formed directly on the carrier member.

This tool is especially designed for dressing the walls of cylinders of internal combustion engines which have been in use for some time. It is known that the constant travel of a piston such as 10 will cause the cylinder walls to be worn to an out of round condition and also leave a ledge of ridge 12 at the upper end of the cylinder 14.

The presence of this ridge is occasioned by the fact that the piston rings do not ordinarily travel entirely to the end of the cylinder bore, and consequently there is not as much wear at this point as upon the portion traversed by the rings.

It is the purpose of this tool to provide means for removing the ledge or ridge 12 and to perform the operation in such manner that the portion operated upon will conform to the worn portion of the cylinder wall, Whether or not such worn portion is truly cylindrical. Thus, when a new piston is installed or when new rings are installed upon an' old piston, the operation of this tool, by removing the ridge referred to, will obviate the condition which might cause a clicking or knocking sound when the piston is operated.

In the form shown in Figures 1, 2 and 3, the body of the tool includes a top plate 16 and a bottom plate 18 which are of substantially conical form and arranged with their points directed toward each other and variably spaced apart. For adjustably connecting the plates 16 and 18 I employ a series of rods 20 which are fixed at their upper ends to the top plate and which extend slidably through the bottom plate 18.

A series of carriers are arranged to cooperate with the top plate 16 and bottom plate 18 and are movably mounted between them. The carriers are formed tapering at their ends for engagement with the opposed conical surfaces of said plates. Two of the carrier members are alike in construction and are designated by the numerals 22 and 24 but the other carrier member 26 is somewhat different. Each carrier member engages slidably at its upper end in a groove formed between parallel flanges 28 on the lower surface of the top plate 16 and each carrier member engages at its lower end in a groove formed between flanges 30 on the upper face of the bottomplate 18. It will be observed that these grooved connections are arranged radially of the device and on inclined lines relative to its axis, thereby permitting an expansion and contraction of the carriers relative to the conical top and bottom plates by radial outward and inward movement.

The top plate 16 and bottom plate 18 are further connected by a screw headed bolt 32, upon the threaded lower end of which is mounted a nut 34. The head of the bolt 32 is located in an angular recess 36 opening to the top of the plate 16,-and this recess is adapted to receive a-suitable tool such as 38 by means. of which the device may be manually rotated. I V

In the lower surface of the bottom plate 18 is formed an angular recess 40 adapted to snugly receive the nut 34 and hold it against turning. An expansion spring 42 is mounted on the bolt 32 within the recess 40 and behind the nut 34. If desired, a pin or key 44 may be mounted through the lower end of the bolt to prevent accidental removal of the nut 34.'

The carrier members 22, 24 and 26 are formed with outwardly opening recesses 46 within which rollers 48 are rotatably mounted on vertically extending pins 50. A separate pin 50 is provided for each of the rollers 48 and is mounted in a bore in the carrier member by endwise movement, after which a set screw 52 is placed in the threaded outer end of the bore for the purpose of holding the pin and roller in place. The rollers 48 are adapted to travel in contact with the walls of the cylinder 14 during the operation of the tool. This contact of the rollers is with that portion of the cylinder wall which is located beyond the ridge 12, or in other words-that portion which has been worn by previous operation of the piston 10 and its rings.

The carrier member 26 is formed in its outer face with a recess 54 in which a cutting or reaming blade 56 is mounted. The blade 56 is mounted rigidly on a laterally extending shank 58 which passes through an opening in the adjacent pin. This particular pin, for convenience in distinguishing it from the others, is designated by the numeral 50' and its roller by-the numeral 48". The bore in which the shank 58 of the blade is mounted extends through the inner face of the carrier member 26 and is tapped to receive an adjusting screw 60 which bears against the inner end of the shank. The adjusting screw 60 may be manipulated for regulating the position of the blade 56. After the desired adjustment has been achieved it is maintained by tightening the set screw 52 at the outer end of the pin 50', thereby exerting pressure on the end of said pin and causing it to firmly hold the shank of said blade.

The cutting edge of the blade 56 is in this instance formed at the upper end margin or on the top of the blade and is adapted to operate during upward movement of the tool. The blade 56 is set and adjusted, by the means just described, so that the outer end of its cutting edge will be in alignment with the outer periphery of the roler 48, which is immediately beneath it, whereby the cutting operation of the blade will conform to the surface against which the periphery of the roller 48' is traveling.

The tool is supported by a threaded tubular stem 62 through which the operating tool 38 may be inserted. The stem 62 is formed at its lower end with a peripheral flange 64 which is attached to the upper face of the head plate 16 by means of screws or the like 66.

Threadedly mounted on the tubular stem 62 is a substantially yoke-shaped bracket 68 whose ends engage on the upper surface of the engine block in which the cylinder 14 is formed, and a stop collar and depth gauge 70 is mounted on the ingly held in position with respect to the head plate 16 and bottom plate 18 by means of one or more endless coil springs '76 encircling said carrier members and preferably mounted in transverse grooves in their outer faces. a

In practical use of this form of the tool, it is placed in position within the upper end of the bore of a cylinder such as 14, the bracket 68 having first been moved upwardly on the threaded portion of the stem 62. In this connection it should be stated that the threaded mounting of the bracket on the stem 62 is preferably by means of a left hand thread. This being true, it follows that when the tool is rotated to the right by turning the wrench 38, the bracket 68 being held against rotation, the tool with be caused to move upwardly in the bracket.

The tool is inserted within the cylinder bore 14 to such extent that the cutting blade 56 is 10- cated beneath the lower edge of the ridge or ledge 12 as indicated in Figure 3. The feet 72 of the yoke 68 are placed on the top of the cylinder block and one of them is caused to engage against a stop which may be a stud 74 mounted in one of the threaded openings which commonly are employed for attaching the cylinder headtothe block. This engagement is for the purpose of preventing rotary movement of the bracket 68 as turning movement is applied to the reaming tool in a clockwise direction through turning movement of the operating tool 38.

A screw driver or the like is then employed for expanding the reaming tool by tightening the bolt 32, it being understood that the nut 34 is held against rotation by engagement in the recess 40. The screw driver may be inserted through the tubular stem 62 to engage the slotted head of the bolt 32.

The tightening of the bolt 32 causes the plates 16 and 18 to be drawn toward each other, thereby forcing the tapered carrier members 22, 24 and 26 outwardly in their seats against the action of the spring 76.

This tightening action is continued until the peripheries of the rollers 48 and 48 engage the inner wall of the cylinder and then is continued somewhat past that point, thereby relieving the tension on the spring 76 and placing the spring 42 under tension and causing a forcible engagement of the guiding rollers with the cylinder walls.

The tool is supported with respect to the cylinder 14 by means of the bracket 68 and its feet 72. The rollers 48 and 48 are in engagement with the worn portion of the cylinder wall and the edge of the cutting blade 56 is positioned just below the ledge or ridge 12.

Rotary movement ina clockwise direction is then imparted to the reamer manually by the use of the wrench or tool 38, and this rotary movement causes the tool to be moved slowly upwardly in the cylinder on account of the left hand threaded connection of its tubular stem 62 with the supporting bracket 68, which as before noted is held against clockwise rotary movement. As the tool is rotated and is moved upwardly, the cutting edge of the blade 56 acts to cut and ream away the projecting ledge 12 and the operation is continued until the blade has reached the level of the upper end of the cylinder and the ridge has been entirely removed.

It will be observed that the carrier members are capable of moving on radial lines relative to the axis of the reamer and that their tendency is to move outwardly on account of the force exerted by the spring 42, which has been placed under compression by tightening the bolt 32. The rollers 48 and 48' consequently are caused to contact at all times with the surface of the cylinder wall 14 regardless of its contour. The position of the roller 48' therefore is always controlled, in operation, by the contour of the wall over which it is traveling and the position of the cutting blade 56 radially is likewise determined by the same condition because the outer portion of its cutting edge is in vertical alignment with the outer periphery of the roller 48. It'follows, therefore, that the cut made by the blade 56 in removing the ledge or ridge will conform to the surface over which the roller 48' is traveling. This means that the reamed portion of the cylinder wall will conform to the portion below it which is engaged by said roller. Consequently, when new piston rings are installed, these rings will travel over a surface which conforms, at the upper end of the cylinder bore, with the contour of the worn portion below.

It should be noted that the angular opening for the tool 38 is always located at the axial center of the reamer, for the carrier members for the rollers and cutting blade are uniformly spaced and radially arranged about the axis of the tool and are caused to move uniformly on radial lines. Considerable expansion of the reamer for work on cylinders of different diameter may be obtained because of the tapered formation of the heads and the ends of the carrier members. The inclined engagement of these members, guided by the flanges 28 and 30, permits easy sliding movement of the carrier members in expanding and contracting the reamer to the desired diameter and in placing the spring 42 under compression when the tool is confined in a cylinder bore.

The roller 48' which is mounted directly beneath the cutter 56 preferably is provided with a felt washer 78 which normally projects slightly beyond the periphery of the roller. When the tool is in use the washer '78 is compressed against the cylinder wall and functions to prevent cuttings from the reaming operation from dropping down between the roller and the cylinder wall and becoming rolled upon the wall surface.

It .will be noted that the roller. 48' serves not only as a guiding means for the tool in its contact with the cylinder wall, but that it also has the function of a stop or gauge for the cutting operation inasmuch as it definitely causes the outward or radial extent ofthe cutting operation to conform to the surface over which said roller 48' is moving.

In Figure 4 I have shown a slightly modified form of a tool of this type. This modification in-' volves the use of a carrier member 26' which is formed with an outwardly opening recess 80. In this recess is mounted a cutting blade 82 which functions as in the previously described construction, by upward movement of the tool. The blade 82 is held in place by a set screw 84 mounted in the upper end of the carrier member.

According to this construction, a guiding and stop member 86 is employed which does not have the characteristics of a roller, but which preferably has a rounded outer end arranged for slid-' ing contact with the cylinder wall. The guiding and stop member 86 is attached directly to the lower face of the cutting blade 82 as by a screw 88 extending through a slot 90 in said member. The member 86 may be adjusted radially relative to the cutting blade 82 and both members may be adjusted radially in the recess to cause th cut to be made of the desired depth.

Similar compression means is employed as previously described to force the carrier member 26 outwardly whereby the guiding and stop member 86 is caused to forcibly contact with the cylinder wall. The edge of the blade 82 is, of course, in alignment with the outer end of the member 86, thereby requiring that the cut made by said blade shall conform to the surface over which the rounded outer end of the member 86 is traveling.

In Figures 6 and 7 is illustrated a modified construction in which a different form is employed for the body of the tool, and also a different means for supporting it although the feeding means is similar to that previously described.

This form of the tool involves a single body member 92 which is chambered to receive a block like carrier member 94 slidably mounted in and projecting from one side of the body member.

The body member. is provided with an upwardly extending stem 96 which in this instance is of solid rather than tubular construction and is formed at its upper end with an angular projection 98 adapted to be engaged by a socketed wrench or tool for turning the device.

The threads of the stem 96 are likewise of lefthand formation and this portion of the stem is engaged by the threaded hub 100 of a bracket having a laterally projecting portion 102 formed with a longitudinal slot 104. The bracket is adapted to be attached rigidly to the top of the cylinder block through a cap screw or the like 106 extending through the slot 104 and seated in one of the tapped openings in the top of the block. A split collar 108 is adjustably mounted on the upper part of the stem to serve as a depth gauge after the tool has been set for operation on the first cylinder of a series. The'expanding means which controls the position of the carrier member 94 in the housing or body member 92 consists of a threaded bolt 110 extending rotatably through a boss 112 on the inner end of the body member and having its head engaging the outer face of said boss. The inner end of the bolt 110 has a threaded engagement with the carrier 94. The bolt 110 may be turned in either direction by employing a hand wrench inserted into the cylinder 14 from above for engaging the head of the bolt and by this means the carrier member may be expanded or contracted relative to the body member.

The intermediate portion of the bolt 110 is formed with a shoulder 114 and a coil spring 116 is mounted on said bolt between the shoulder and the inner face of the end of the boss 112, thereby providing a yielding mounting for the carrier member, and permitting the spring to be placed under compression when the carrier member is expanded or moved outwardly against the wall of the cylinder.

The opposite or outer end portion of the carrier member 94 is formed with an outwardly opening recess 118 in which a cutting or reaming blade 120 is slidably mounted, the blade in this instance being backed by an expansive coil spring 122 located within the recess.

A guiding roller 124 is also carried by the outer end of the carrier member 94, beneath the blade 120, and having a portion projecting beyond the end of the carrier member for engagement with the wall of the cylinder such as 14.

To provide a convenient means for adjusting the blade 120 in its seat, so that its outer. edge may be caused to conform to and be in alignment with the periphery of the roller 124, I have supplied an adjusting screw 126 which has a threaded engagement with the wall of the carrier member 94 and which has at its inner end an off center stud 128 projecting within and eccentrically of a circular opening 130 in the blade. The adjusting screw 126 may be turned by the use of a screw driver for causing the off center stud 128 to engage any desired portion of the wall of the enlarged opening 130, thereby moving the blade 120 inwardly in the recess 1 18 or permitting it to be moved outwardly under the influence of the spring 122.

In practical operation the blade 120 is first adjusted to such position that its outer edge is in line with the outer periphery of the roller 124, the hub 100 of the bracket is moved upwardly on the threaded stem 96, and then the tool is placed in the cylinder to be treated, in such.

manner that the blade 120 is located immediately below the ridge 12. The tool is properly centered relative to thecylinder 14 in any suitable manner and then the bracket 102 is rigidly secured the roller and blade firmly but yieldingly against the cylinder wall.

The reamer is rotated in clockwise direction by means of a wrench engaging the projection 98, and this rotary movement causes the blade 120 and roller 124 to travel over the surface of the cylinder 14. stem 96 with the threaded portion of the supporting bracket also causes the tool to be elevated or moved upwardly, and thus the blade 120 accomplishes the reaming or cutting away of the ridge 12, the movement being continued until the blade reaches the top of the cylinder.

In the operation the cutting element 120 is yieldingly pressed outward by the spring 122 to the limit of its outward movement as defined by the on center stud 128 of the adjusting screw as previously .described. The entire .carrier member 94 with the roller and blade are also pressed outwardly and kept under compression by action of the spring 116 so that the roller is caused to forcibly engage the cylinder wall at all times of the movement of the tool, and the cutting action of the blade 120 is caused to conform to the travel of the roller 124 on the wall of the cylinder below.

In the form shown in Figure 8 the same type of body member 92 with threaded stem 96 and The threaded engagement of the and which is caused to bear against the inner face of the boss 112 on the body member, thus changing the device from a yielding expanding means to a solid expanding means.

The carrier member 132 is formed at its opposite end with an end opening recess 137 in which a blade 138 is slidably mounted and is backed by a spring 140. In this particular form of the tool, as in connection with Figure 4, I have shown a guiding and stopelement 142 which is not rotatably mounted, but which is fixed directly to the blade 138 and which slidably engages at its outer end with the wall of the cylinder. The mounting of the guiding element 142 is accomplished by means of a screw 144 extending through a slot 146 in said element, thus permitting its adjustment relative to the blade for the purpose of aligning their outer edges.

In this form of the tool the operation is quite similar to that described in connection with Figures 6 and 7 except that dependance for the yielding mounting of the blade and for its yielding engagement with the work is :placed'entirely on the backing spring 140 inasmuch as the carrier 'member itself is not permitted to move-after it has been adjusted to such position that the blade 138 and guide 142 are brought into forcible contact with the cylinder wall and the spring '140 compressed.

As before, the action of the cutting element, in a direction radially of the cylinder, is-limited and determined by the engagement of the guiding member 142 with the cylinder wall below the point of cutting contact and thereby the cutting operation is caused to conform-to the part engaged by said member 142.

In Figure 9 a form offe'eding means is shown, involving a slightly different operation of the cutting element. The same kind of a body member 92 is employed having a boss 112 thereon and the expanding screw 110 may be such as to involve either the spring pressed or the solid expanding means of the forms previously described in connection with Figures 6 and '7 on the one hand and Figure 8 on the other.

The body or housing 92 is formed with an up wardly projecting stem 148 which is plain, or in other wordsunthreaded-. It engages rotatably in the plain bearing or hub 150 of a bracket 152,

which is fastened to the top of the cylinder block in the same manner 'as the bracket 102 previously described. The stem 148 is formed with an angular projection 154 to which a socketed wrench may be applied for rotating the tool and the hub 1500f the bracket is confined on the stem by a split clamping collar 156.

The housing or body 92 receives slidably a carrier member 158 which carries a cutting blade 160 and a guiding roller 162 in line therewith. The cutting element 160 may be slidably mounted and provided with a backing spring as described in connection with some of the previous forms, or it may have a simple adjusting means for causing its outer edge to be aligned with the roller blade 160 is caused to engage the face or inner side of the ridge 112 and it operates by outward movement on a radial line under the influence of the yielding means that may be provided therefor. It should be borne in mind that this yielding means may be in the nature of a compression spring such as 116 (Figure 7) for the expanding means, or it may be in the nature of a backing spring such as 122 or 140, or both of such yielding compression means may be employed if desired.

When the tool shown in- Figure 9 is-rotated, there is of course no upward movement because the threaded connection of the stem with the support is omitted. There is simply a rotary movement in the same plane and the cutting operation is caused by outward radial movement of the cutting element 160 as it turns, the cutting action being terminated or limited by engagement of the roller 162 with the cylinder wall below, thereby causing the cut to conform to that portion of the wall engaged by the roller.

Figures 10 and 11 disclose further modifications with respect to the carrier member, cutter and stop or guide. These forms of the tool both apply particularly to the same general type illustrated in Figures 6 to 9 inclusive, in which a single carrier member is provided.

In Figure 10 the carrier member is designated as 165 and it is normally slidably mounted in a housing or body member 116 and may be provided with an expansion spring 167 backing it. The spring 167 is coiled on an adjusting bolt 168 having a threaded engagement with the carrier member in a manner similar to that previously described in connection with Figure '7. The spring engages at one end against the house 166 and at its opposite end against a shoulder 169 formed on thebolt.

The carrier member 165 is made of tool steel and is ground in such manner as to form an integral cutting element 170 which may operate either vertically or radially as previously described. This form involves a rotatably mounted roller 171 which may be aligned with the outer edge of the cutting element 170. As hereshown the roller 171 is carried by a separate block 1'72 which is slidably mounted in an outwardly opening recess 174 in the carrier member and which is provided with an adjusting screw 1'76 having a threaded connection with the carrier member. The screw 176 may be adjusted to line up the roller with the cutting element and in the operation of the tool the action of the cutting element is caused to conform to the surface engaged by said roller.

The disclosure of Figure 10 involves a new feature or element which it may be desirable to employ at times. There may be occasions when it is desirable to use the tool without the yielding expansive means or to render said means inoperative so that a bore may be cut in a true circle. For this purpose I have provided a set screw 17'? which has a tapped seat in the housing 166 and which may be tightened down at times against the carrier member 165. This provides a means for locking the carrier member and cutting element against the action of the spring 167, to make the yielding expansive means temporarily inoperative. A portion of the ridge immediately above the upper piston ring can be removed in the regular way to conform 'to the worn part of the cylinder and then by setting the screw 1'77 and locking the expansive means, the remainder of the ridge to the top of the bore can be cut to a true cylindrical shape, and thus conform with the original bore of the cylinder. It is to be understood that this locking feature may be employed in connection with other forms of the tool besides the specific form illustrated in Figure 10.

According to Figure 11 the carrier member 1'78 is made of tool steel and is again formed with an integral cutting element 180. It is also formed with an integral guide and stop member 182 which has its outer edge in alignment with the cutting edge of the element 180 and which has a sliding engagement with the wall of the cylinder so that the cutting operation is caused to conform to the contour of the part engaged by the member 182. The carrier member 178 is provided with an adjusting screw 184 having 3 threaded connection therewith and rotatably mounted in the housing which carries the carrier member in a manner previously described. The adjusting screw 184 is formed with a shoulder 186 which is engaged by a compression or expansion spring '188, which is necessary in this'instance to press the carrier member 178 and its integral elements 180 and 132 into yielding contact with the cylinder wall.

It is obvious from this disclosure that many different modifications may be employed for accomplishing the purpose of removing the ridge or ledge in such manner that the portion treated will conform to another portion of the cylinder 105 wall which is engaged by a traveling guide memher.

The essential requirements are that suitable supporting means must be employed for the-tool, permitting it to rotate and permitting the cutting 110 element to be yieldingly advanced toward the work, together with a guide means which travels on a portion of the cylinder wall and which is in alignment with the cutting member or with the final position of the cutting member, to limit the cutting operation so that it conforms to the part engaged by said guide member.

Some of the embodiments of the invention disclose'that the guiding and limiting functions may be accomplished by the same member and that 120 this member may, if desired, be connected directly to the cutting element. The different embodiments disclose different ways that these various functions may be accomplished, including the feature of carrying out the cutting operation during upward movement of the tool through a threaded connection with the support.

The different modifications herein illustrated and described are given as illustrations or examples of difierent means whereby my purposes and objects may be accomplished and I do not desire to be understood as limiting myself to any specific structure except as defined by the scope of the appended claims.

Y I claim as'my invention:

1. In a ridge reaming tool, a body member, a carrier member arranged for movement laterally with respect to the body member, a cutting element carried by said carrier member, yielding compression means acting to urge said cutting element outwardly toward the work, means for rotating the tool in a cylinder, a part on said carrier member adapted to engage the cylinder wall below a ridge thereon as the tool is rotated,- to limit outward movement of the cutting element under the influence of said yielding means, a stationary support, and a threaded connection between said tool and the support for causing the tool to be advanced in the cylinder as it is rotated 15;)

to remove said ridge and form the portion of the cylinder wall in registry therewith, with the same contour as the portion below said ridge.

2. In a ridge reaming tool, a body member adapted to be inserted within a cylinder having a ridge near its top end, a carrier member arranged for sliding movement laterally with respect to the body member, rotary threaded means for adjusting said carrier member, a cutting element slidably mounted for lateral movement relative to said carrier member and initially positioned below said ridge when said body member is inserted within said cylinder, a backing spring engaging said cutting element and urging it toward the cylinder wall, a threaded feeding means causing said cutting element to be advanced upwardly, and a member mounted on and carried by said cutting element for engaging the cylinder wall below the ridge thereon, to limit the operation of said cutting element under the influence of said spring and thereby form the upper end of the cylinder with the same contour as that portion below said ridge.

, 3. In a cylinder ridge reamer, a body member adapted to be inserted within a cylinder, a carrier member arranged for movement relative to the body member, in a direction radially-of the cylinder, a cutting element carried by the carrier member, yielding means adapted to be placed under compression when said carrier member is expanded, for urging said cutting element toward the work, means for rotating said body member and at the same time causing it to advance longitudinally of the cylinder for removing a ridge therefrom and a guide and stop member carried by carrier member and adapted to engage and travel on the portion of the cylinder wall out of alignment with said ridge during the movement of the tool, for guiding the travel of said cutting element and for limiting its cutting operation to form the portion of the cylinder wall covered by said ridge, with the same contour as said portion out of alignment therewith.

4. In a tool for reaming a ridge in a cylinder, a bracket adapted to be secured at the top of the cylinder,.a tool body adapted to enter the cylinder, a cutting element carried by the body, yielding means acting to urge said cutting element outwardly toward-the work, a member carried by the body for engaging the cylinder wall at a point below said ridge, to limit the depth of the cut of said cutting element, a stem on said body having a threaded engagement with said bracket, and means for rotating said body, cutting element and limiting member, whereby they are advanced longitudinally of the cylinder because of such threaded connection, and said ridge is removed to cause the portion of the cylinder covered thereby to conform to the contour of the portion below said ridge.

CARL A. OLSON.

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