US2618182A - Knurling tool for internal cylindrical surfaces - Google Patents

Description

R. R. TEETOR Nov. 18, 1952 KNURLING TOOL FOR INTERNAL CYLINDRICAL SURFACES Original Filed Nov. 18, 1946 h m. mt- 5 INVENTOR.

with the heat of the engine, the intimate contact therebetween is maintained. Such intimate contact provides for a more rapid transfer of heat from the sleeve to the cylinder block, thus improving the condition under which the sleeve operates. In the present instance, the metal is placed under stress by outward deformation at closely spaced points, areas or lines throughout a band at the end of the sleeve. While such deformation of the metal may be attained by peening, spinning or rolling, knurling of the internal surface of the sleeve throughout this band is preferred. The knurling is of sufficient depth to force the metal outwardly to form a slight bell at the end of the sleeve with the belled portion firmly abutting the bore of the cylinder block to provide the intimate contact necessary to prevent seepage of oil therebetween and to increase the rate of transfer of heat from the sleeve to the cylinder block. The knurling provides rounded points or ridges between the grooves thereof, which conform to the inner diameter of the major portion of the liner and places the metal throughout this area in a stressed condition.

To illustrate the use for which a tool embodying the invention is adapted, I have shown in Figs. 1, 2 and 4 of the drawing a fragmentary portion of a cylinder block casting It provided with a cylinder bore H adapted to receive a sleeve 12. The sleeve I2 may extend throughout the length of the cylinder bore l I so that the piston for the cylinder will operate within the sleeve. The cylinder block casting, as is usual, is provided with a flat end surface 13 against which a cylinder head is adapted to be secured by means of bolts extending into threaded holes is in the cylinder block casting. The sleeve l2, at its upper or combustion chamber end, is preferably rounded as at I? (see Fig. 4) to facilitate insertion of a piston within the sleeve and is flush with the surface I 3.

As illustrated in Fig. 4, an annular area or band I6 is to be knurled to a depth and with sufficient pressure to outwardly deform the metal within the band into close intimate contact with the bore l I. face of the sleeve resulting from the knurling preferably are aligned with the inner surface of the major portion of the sleeve so that the piston can be inserted and withdrawn through the knurled end of the sleeve without interference from the knurling. The knurlin may be of any desired type, that is, it may be formed by crossed grooves, resulting in points between the rooves, or it may be formed by grooves extending only in a single direction to produce ridges therebetween. The principal feature, however, of the knurling is to force the metal outwardly into intimate contact, as indicated at IT, with the bore H.

A tool embodying the invention provides a simple means for effecting such knurling. The tool herein illustrated is shown as hand operated, although it of course may be power operated, and is adapted to be readily mounted on the cylinder block to perform the knurling operation. I its preferred form, the tool comprises a support in the nature of a bridge member 20 spanning the end of the cylinder and provided with bolt holes 2! adapted to be registered with the cylinder head bolt holes 14 in the cylinder block casting. Bolts 22 are inserted through the holes 2| in the bridge member 20 and are threaded into the holes M in the block to rigidly secure thebridge member in place.

The points or ribs on the inner sur- The bridge member is provided with a central aperture 23 adapted to be aligned with the cylinder bore and to receive a bushing 24 therein, the aperture 23 and bushing 24 being threaded to provide adjustment axially of the cylinder. The bushing 24 is formed with a head 25 at its upper end by which the bushing may be rotated to adjust it within the bridge member 20, and a lock nut 26 is mounted on the bushing to rigidly lock it in place within the bridge member after it has been adjusted. The bushing is provided with a central bore 30 in which a spindle 3| is rotatably mounted. The spindle 3|, at its lower end, is provided with a flange 32 while at its upper end a collar 33 is keyed thereto and secured by a setscrew 34. The collar 33 is hexagonal in form so that a wrench may be placed thereon to rotate the spindle 3| within the bushing 24. Thrust washers 35 are preferably interposed between the flange 32 and the bushing 24 and between the collar 33 and the head 25 of the bushing.

The spindle 3| is arranged to carry knurls adapted to be positioned within the upper end of the cylinder sleeve I 2 with the knurls arranged so that they may be expanded outwardly to bear against the sleeve. To this end, a plate is mounted in spaced parallel relation to the flange 32, the plate 40 being secured to the flange by means of rivets ll (see Fig. 3). Mounted between the flange 32 and the plate 3%] is a plurality of rocker arms 62 pivotally supported by the plate and flange on axes eccentric to the axis of the spindle but symmetrically arranged relative to the spindle.

Thus, each arm is pivotally carried by a pivot pin 43 mounted adjacent the periphery of the flange 32 and plate 40. Each rocker arm is generally triangular in form with one corner thereof pivoted by the pin 43 and another corner carrying a knurl 4 t rotatably supported in a notch in the rocker arm by a pin 45.

The rocker arms42 are adapted to be swung outwardly about their pivots 43 to cause the knurls 44 to bear against the internal surface of the sleeve l2. To force the knurls outwardly, each rocker arm 42 is provided with a tapered surface 43 at its third corner, adapted to cooperate with a tapered o-r conical nut 41 mounted concentrically with the spindle so as to 00- act with all of the rocker arms. To provide for insertion and movement of the nut 41, the plate 40 has a central aperture 48. As will be apparent by inspecting Fig. 3, the line of contact of the nut 41 with each surface 46, the axis of the associated knurl 44, and its line of contact with sleeve I2 all lie substantially in the same axial plane. Thus, the pressure exerted by the nut 41 is directly aligned with knurl so that very little stress is placed on the pivot pins 43.

The nut 47 is adapted to be adjusted axially of the spindle to effect swinging movement of the rocker arms #2. To this end, the nut 41 is threaded on a bolt 50 extending through the spindle 3l with the head of the bolt, indicated at 5|, located adjacent the collar 33. By turning the bolt 50, the threaded engagement thereof with the nut 41 adjusts the nut axially of the spindle to move the rocker arm-s outwardly.

In using the tool heretofore described, the bridge member 20 is placed over the end of the cylinder with the bolts 22 threaded into the holes It. The bolts 22 are not tightened down until the tool is properly centered with relation to the to shift to a slight extent relative to the bolts 22 by virtue of the fact that the bolt holes 2| through the bridge member 20 are somewhat larger than the diameter of the bolts. Such p0- sitioning of the bridge member 20 brings the rocker arms with their knurls in position to enter the end of the cylinder liner. In order to adjust the knurls longitudinally of the cylinder so that they will act on the desired portion of the liner, the spindle may be adjusted axially by means of the bushing 24 and its threaded connection with the bridge member 20. After the bushing 24 has been adjusted to the point where the knurls are properly positioned, it is locked in place by means of the lock nut 26.

The bolt 59 is then turned to draw the nut 41 upwardly and swing the rocker arms 42 outwardly to bring the knurls into bearing engagement with the sleeve l2. Such outward movement of the knurls 44 will cause the tool to be centered with the cylinder sleeve, since the bridge member may shift slightly relative to the bolts 22 before the latter are tightened. When the device is so centered, the bolts 22 are then tightened to rigidly clamp the bridge member 20 to the cylinder block.

The device is then ready for the knurling operation, which is accomplished by turning the bolt 50 to draw the nut 41 upwardly and thus cause the knurls M to bear outwardly against the sleeve l2 with sufficient pressure to deform the metal of the sleeve. The spindle is then rotated by placing a wrench on the collar 33 to roll the knurls entirely around the circumference of the sleeve, the bolt 50 being adjusted during the rotation of the spindle to achieve the desired deformation of the metal of the sleeve. In this instance, the resultant ridges formed by the knurling operation in the inner surface of the sleeve are held to the same diameter as the unknurled inner surface of the sleeve. As a result of this knurling operation, the metal of the sleeve is forced outwardly and placed under stress so that it has a s-ufiiciently intimate contact with the bore of the cylinder to prevent entrance of oil between the sleeve and the bore.

With the tool described above, positioning of the tool in centered relation with the cylinder is accomplished by the knurls themselves, which are thereafter forced outwardly by their adjusting means to effect the knurling operation. Such operation can be readily performed by hand since the spindle 3| can easily be rotated to move the knurls about the inner periphery of the sleeve by placing a wrench on the collar 33.

I claim:

1. A tool for knurling an internal cylindrical surface within an article, comprising a bridge member adapted to span one end of said surface and to be secured to said article, a bushing threaded into said bridge member and adapted to be positioned with its axis coincident with that of the cylinder when the tool is set for operation, a spindle journaled in and held against endwise movement relative to said bushing and adjustable axially by adjustment of the bushing in said bridge member, said spindle having an axial bore and a flange at one end, a plurality of rocker arms pivotally connected to said flange for movement radially of said spindle and disposed symmetrically about the axis of said spindle, a plurality of rotary knurls carried by the respective rocker arms, a bolt extending through said spindle bore, and a conical nut threaded on said bolt and engaging said rocker arms, said nut being movable axially of the spindle by rotation of said bolt and being operable when moved in one direction to swing said rocker arms outwardly and thereby force said knurls into pressing engagement with said surface.

2. A tool for knurling an internal cylindrical surface, comprising a supporting member adapted to span one end of said surface and having an aperture adapted to be positioned with its axis coincident with that of said surface, a spindle extending through said aperture and having an axial bore, a plurality of knurl-supporting members movably carried by said spindle at one end thereof for movement radially of the spindle, a plurality of rotary knurls mounted on the respective knurl-supporting members, a threaded rod extending through said bore and having a head element at one end and a nut element threaded on the other end, one of said elements being conical in form and engaging said knurl-supporting members, the other of said elements engaging said spindle whereby rotation of said other element will adjust said conical element axially to move said knurl-supporting members outwardly, and a bushing threaded in said aperture and holding said spindle against endwise movement relative to the bushing, whereby the position of said knurls may be adjusted axially of said surface by rotation of said bushing.

3. A tool for knurling an internal cylindrical surface comprising a rotatable spindle having an axial bore, a plurality of knurl-supporting members supported on one end of said spindle for movement radially thereof, a plurality of rotary knurls carried by the respective knurl-supporting members, conical means located on the axis of said spindle between said knurl-supporting members and adjustable axially of the spindle for moving the said knurl-supporting members outwardly, means extending axially through said bore for adjusting said conical means, a support adapted to span one end of said surface and having an aperture adapted to be positioned coaxially with said surface, and a bushing having said spindle secured therein against endwise movement but freely r0- tatable therein, said bushing being threaded in said aperture whereby said knurls may be adjusted axially of said surface.

RALPH R. TEETOR.

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

UNITED STATES PATENTS Number Name Date 405,226 Schaubel June 11, 1889 911,172 Stavenik Feb. 2, 1909 964,272 Kaiserman July 12, 1910 1,837,624 Maupin Dec, 22, 1931 2,155,542 Graham Apr. 25, 1939 2,409,219 Maxwell Oct. 15, 1946 FOREIGN PATENTS Number Country Date 12,341 Great Britain Sept. 12, 1884 84,261 Sweden Sept. 3, 1935 555,237 Great Britain Aug. 11, 1943

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