US2219245A

US2219245A - Crankpin turning tool

Info

Publication number: US2219245A
Application number: US240967A
Authority: US
Inventors: Isaac D Zitzerman
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-11-17
Filing date: 1938-11-17
Publication date: 1940-10-22
Anticipated expiration: 1957-10-22

Description

Patented Oct. 22, 1940 UNITED STATES PATENT OFFICE 11 Claims.

This invention relates to turning tools, particularly for truing the pins of a crankshaft Without removal thereof from its operating position, and has for its principal object to provide a tool of this character which is extremely accurate'in operation and smoothly faces the cylindrical surfaces of a crankpin as well as the fillets and cheeks of the crank.

Other objects of the invention are to provide a tool of this character adapted for turning crankpins of different diameter with extreme accuracy; to provide the tool with a secure cutter mounting to avoid chatter during cutting operation of the tool; to provide a cutter having a cutting edge arranged to engage the crankpin in a plane passing through the axis thereof regardless of its diameter, the diameter, of course, being within the capacity of the tool; to provide the tool with interchangeable cutters and tool positioning guide pins corresponding to the width of the crankpin to be acted upon; and to provide a cutter having a plurality of cutting edges any one of which may be used by selectively positioning the cutter.

Further objects of the invention are to provide a tool that is readily applied to the crankpin; to provide a tool with means to compensate for wear of the guide pins securing the respective sections thereof; and to provide adjusting screws with a micrometer scale to indicate the amount of cut upon each revolution of the tool.

In accomplishing these and other objects of the invention, as hereinafter pointed out, I have provided improved details of structure, the preferred form of which is illustrated in the accompanying drawing, wherein:

Fig. 1 is a perspective view of the lower portion of a crankcase of an internal combustion engine, showing the oil pan removed and my improved turning tool applied to one of the crankpins.

Fig. 2 is a sectional view through the tool.

Fig. 3 is a side elevational view of the upper half of the tool, part of which is broken away to show the adjusting screw for tightening the guide pins in case of wear.

Fig. 4 is a section on the line 4 4 of Fig. 2.

Fig. 5 is a detail perspective view of the parts of the turning tool shown'in disassembled spaced relation to better illustrate the construction 0 thereof.

Referring more in detail to the drawing:

I designates a turning tool constructed in accordance `with the present invention, and which includes a substantially ring-like body 2 composed of mating,

arcuate sections

3 and 4. The

` commodate the guide pins 9 andIII which are

sections

3 and 4 are of less width than the minimum width of pin on which the tool is to be used so that it is freely rotatable about the axis of a pin a between the cheeks b and c of a crank d, The inner arcuate faces 5 and 6 of the respective sections are of suitable diameter to accommodate the largest size pin for which the tool is to be used, and the outer arcuate faces 1 and 8 are of suihcient diameter to give the required rigidity and metal necessary in mounting the connecting 1 guide pins 9 and I0 by which the sections are interconnected. The adjacent end faces II and I2 of the respective sections extend on parallel planes so that the sections may be brought closely together when applied to a crankpin of miniu mum diameter.

Extending inwardly from the faces I2 of the respective sections are cylindrical bores I3 to acseated therein and drawn tightly against the bottom I4 of the bores by fastening devices, such as llister screws I5, having heads countersunk within bores I6 formed within the arcuate faces 1 and 8 of the respective sections and in axial registry with the bores I3. The Shanks n of the 25 screws extend through axial openings I3 in the sections and into threaded sockets I9 formed in the ends of the respective guide pins. The heads of the screws are provided with hexagon shaped sockets 2li or the equivalent, whereby the screws 8 are adapted to be rotated with the aid of a suitable tool to tighten the pins rmly within their respective bores I3. The guide pins are of sufilcient length to project from the faces I2 to form guide portions slidably receivable in registering 85 bores 2I extending inwardly from the faces II at the opposite sides of the respective sections. The projection of the pin I0 is greater than that of the pin 9 so that the pin I0 is caused to enter its receiving bore ahead of the pin 9 to facilitate assembly, as later described.

The pins 9 and I0 are provided with axial bores 22 having internal threads to be engaged by the threaded shanks 23 of adjusting screws 24, the shanks of the adjusting screws being extended through openings extending through the bottom of the bores 2l toward the outer periphery of the sections where they terminate in counterbores 25 to accommodate the cylindrical heads 26 of the adjusting screws. within one side of the counterbore and are provided with micrometer scales 21, the divisions of which are adapted to register with zero scales 23 on thev respective sections, as best shown in Fig. 5. The heads of the adjusting screws are provided The heads 26 are exposed 50 with hexagonal sockets 29 for the insertion of a suitable tool whereby the screws are rotated to thread the shanks thereof to and from the threaded bores 22 of the guide pins, thereby connecting and disconnecting the sections and effecting adjustment in spacing thereof to accommodate crankpins of different diameters.

In order to automatically move the sections apart upon unthreading of the adjusting screws, the bores 2| have coil springs 30 sleeved over the shanks of the adjusting screws and having one end bearing against the bottom of the bores 2| and their opposite ends against the ends of the guide pins.

After the tool has been in use for some time, it is possible that the guide pins may wear relatively to the bores 2|, which wear would interfere with successful operation of the tool. The ends of the sections having the I`bores 2| are therefore slotted as shown at 3|, with the slots intersecting openings 32 that are formed radially in the outer arcuate faces l and 8 of the sections and intersect with the bores 2| to provide sufflcient flexibility on the respective sides ofthe guide pins to permit snug clamping thereof within their respective bores by iillister screws 33 having their heads 34 rotatably mounted in a counterbored opening at one side of the sections and their shanks 35 threaded in openings 36 at the opposite sides of the sections. Formed in the arcuate faces 1 and 8 of the sections are sockets 31 whereby a suitable handle or bar 38 may be inserted to effect rotation of the tool, as later described.

In the form of the invention illustrated, the section 3 constitutes a support for a cutter 39 and a plunger assembly 49, while the section 4 supports spaced seating plates 4| and 42 for seating the tool against the crankpin a. 'I'he cutter 39 is best shown in Fig. 5 and constitutes a flat blade having side faces 43, edge faces 44, and end faces 45. The junctures of the faces 43 and 44 form cutting edges 46 adapted to remove material from the circumference of the pin a and the juncture of the faces 43 with the end faces 45 form cutting edges 41 to remove material from the cheeks b and c of the crank. The corners of the cutter are rounded, as atv 48, to form the llets e of the crank so that the crankpin, cheek faces and fillets are simultaneously surfaced upon actuation of the tool, as later described.

'I'he cutter 38 is seated in a transverse groove 49 extending inwardly of the arcuate face 5 and which forms a shoulder 50 against which the cutter is rigidly secured by a wedge member 5| having one side bearing against the cutter and its opposite side against the opposite side or shoulder 52 of the groove as shown in Fig. 2. The wedge plate is drawn into wedging relation with the cutter by flllister screws 53 having their heads 54 rotatably mounted in oounterbores of the wedge and their shanks 55 extending through registering openings 56 into threaded sockets at the bottom of the groove. The shoulder 50 is so positioned in the section 4 that when one side face of the cutter is wedged thereagainst the opposite side face will lie in a plane extending through the axis of a crankpin to which the tool is applied. The cutting edge 46 thereof therefore contacts the cylindrical surface of the pin at the diametrical axis thereof and the adjacent edge face 44 cooperates with the cylindrical surface to provide sufcient clearance at the retractive side of the cutter when the tool is rotated about the axis of the crankpin in the direction of the arrow.

In order that the cutting edge of the cutter, when positioned as shown in Fig. 2, will at all times remain in a diametrical plane with respect to the crankpin regardless of the diameter thereof, I have found that the cutter must be positioned at substantially 24 from the median line of the arcuate face 5 of the section 3. It is also essential that the plates 4| and 42 have plane surfaces for tangentially contacting the cylindrical surface of the crankpin, that the seating plate 42 be located directly opposite the cutter and that the plane surfaces be located at right angles to each other, as shown in Fig. 2. The seating plates 4| and 42 preferably have dovetail edges 51 and 58 to engage in dovetail grooves 59 provided inthe arcuate face 6 of the section 4. The pin contacting faces 69 of the seating plates are preferably flat so that they extend tangentially with respect to the cylindrical surface of the'crankpin. In order to firmly retain the seating plates 4| and 42 in tangential contact with the crankpin to be resurfaced, the'section 3 is provided with the plunger assembly 40 which is located therein diametrically opposite to the midpoint between the seating plates 4| and 42. The plunger assembly includes a bar 6| slidable in a slot 62 extending transversely of the arcuate face 5. The bar 6| has a central, internally threaded shank 63 slidable in a bore 64 registering with the slot 62. The bore 64 has an internal shoulder 65 to be engaged by a collar 66 on the shank 63. The inner end of the bore terminates short of the outer face of the section 3 to form a spring seat 61. Formed in the arcuate face 1, in axial alignment with the bore 64, is a bore 68 to accommodate the head 69 of a retaining screw 10, the shank of which extends through a guide opening and into the threaded socket of the shank 63 In order to pressingly retain the plunger against the work, the shank of the screw carries a coil spring '|2 having one end bearing against the spring seat and its opposite end against the shank 63 as clearly shown in Fig. 2.

In order to cooperate with the cutter in centering the tool between the cheeks b and c of the crank d, the section 4 is provided with a transverse opening 13 in which is slidably mounted a guide pin `|4 corresponding in length to the cutkter so that the ends 15 of the pin engage the respective cheeks, thereby retaining the outer side faces of the tool parallel with the cheeks b and c.

In using a tool constructed as described for resurfacing a crankpin a, it is only necessary to remove the oil pan of the engine. The connecting rod bearing is then removed from the crankpin to permit application of the turning tool, it being unnecessary to remove the connecting rod or piston. When the piston is moved to the top of the cylinder the connecting rod is carried therewith which leaves sufficient room therebelow to operate the tool. The adjusting screws 24 of the turning tool are then removed from the guide pins so that the sections of the tool may be separated to permit application thereof to the crankpin. Prior to application of the tool, however, a cutter 39 of proper length is inserted in position within the section 3 and securely tighttened by the wedge element. then placed about the pin to be surfaced so that the guide pin ||I enters the bore 2| of the section 4 prior to entrance of the guide pin 9 in the bore 2| of the section 3. This is an important feature since it facilitates mounting of the tool on the crankpin. The adjusting screws are then The sections are reapplied to secure the sections together and draw the

sections

3 and 4 so that the seating plates 4I and 42 contact one side of the bearing pin and the plunger 6I the opposite side, thereby centering the tool for rotation about the axis of the pin. The adjusting screws are drawn up until the cutting edge of the cutter engages the cylindrical periphery of the pin so that when a bar is inserted in the sockets 31 to rotate the tool in the direction of the arrow, Fig. 2, surface is removed from the crankpin to form a true cylinder. Since the cutting edge of the cutter is at all times kept in substantially the diametrical axis of the pin, and the plates 4I and 42 seated against the opposite sides thereof by the plunger, the tool will not chatter when rotated. The cut is, therefore, smoothly uniform and true cylindrically with respect to the axis of the pin. The ends of the cutter and the rounded corners thereof also form cutting edges which true up the cheeks b and c as well as the fillets at the ends of the pin. The amount of each cut may be noted by the micrometer scales on the heads of the adjusting screws so that the desired reduction may be e'iected in the size of the pin.

.When the tool is to be applied to a smaller shaft, as` shown by the dotted lines in Fig. 2, the plates 4I and 42 will maintain their tangential contact with the smaller shaft and the drawing together of the sections will move the cutting edge of the cutter downwardly toward the smaller shaft in a plane parallel with the vertical axis as respectively indicated by the plane lines J6 and l1.

From the foregoing it is obvious that I have provided a turning tool adapted for accurate work and which will simultaneously finish all of the bearing surfaces of a crankpin with a single application of the tool. It is also obvious that the tool is readily applied to a crankpin without removing the crankshaft from its operating position since the tool may be readily rotated about the shaft by alternating engagement of the turning bar with respect to the sockets 31 in the respective sections.

What I claim and desire to secure by Letters Patent is:

l. A device of the character described including a pair of mating sections having arcuate inner faces, adjusting means connecting the sections about a cylindrical object to be surfaced, a pair of seats in the arcuate face of one of the sections arranged to engage the cylindrical surface of said object, a cutter carried by the other section and located diametrically opposite one of the seats, a plunger slidable in the section having the cutter, a bar carried by the plunger and provided with an edge portion for contact with said cylindrical surface, a spring engaging the plunger and urging the bar toward said seats to retain said seats in contact with the cylindrical surface acted upon by the cutter, and a screw having threaded connection with the plunger.

2. In a device of the character described, a pair of mating sections having arcuate inner faces, adjusting means connecting the arcuate sections about a cylindrical object to be surfaced, a pair of seats in the arcuate face of one of the sections having plane surfaces arranged to engage tangentially the cylindrical surface of said object with said points of tangency substantially 90 part, a cutter carried by the other section and having a cutting edge located in a plane offset at an angle of substantially 24 from a plane pas-sing through the axes of said arcuate inner faces, and a spring pressed plunger slidable in the section having the cutter and offset on the opposite side of said axial plane to retain said seats in contact with the cylindrical surface acted upon by the cutter. i

3. In a device for surfacing crankpins of crankshafts, a pair of mating sections having substantially arcuate inner faces, meansadjustably connecting the sectionsabout a crankpin to be surfaced, a pair of seats in the face of one` of the sections arranged to engage the cylindrical surface of the pin, a cutter carried by the other section and located diametrically opposite one of the seats, and a lateral guide pin slidably mounted in the section having the seats with its axis extending parallel with the axes of the sections to cooperate with the cutter in maintaining the sections in right-angular relation to the axis of the crankpin.

4. A device for surfacing crankpins of crankshafts including a pair of mating sections having substantially arcuate inner faces, adjusting means connecting the sections about a crankpin to be surfaced, a pair of seats in the arcuate face of one of the sections arranged to engage the cylindrical surface of the crankpin, a cutter carried by the other section, said section having the cutter being provided with a radial bore extending therethrough and provided with a spring engaging seat, a. plunger slidable in the bore, a spring having one end engaged against the plunger and the other against said seat, and a screw slidable in the bore and having threaded connection with the plunger to adjust spacing of the plunger relatively to said seats.

5. In a turning tool of the characterl described, a pair of mating arcuate sections, parallel guide pins inl opposite ends of the respective sections and slidably engageable in aligning bores in the opposite facing ends of the sections, adjusting screws rotatably mounted in the ends of the sections having the bores and threadedly engaging the guide pins to move said sections toward each other, a spring on each adjusting screw to move the sections apart when the rotation of thev screws is reversed, a cutter supported by one of the sections, and seating plates supported in the other section and cooperating with the cutter tov engage a cylindrical surface of a crankpin upon manipulation of the adjusting screws.

6. In a turning tool of the character described, a pair of mating arcuate sections, guide pins in opposite ends of the respective sections and slidably engageable in aligning bores in the facing ends of the sections, adjusting screws rotatably mounted in the sections and threadedly engaging the guide pins to move 'said sections toward each other, a cutter supported by one of the sections, seating plates supported on the other section and cooperating with the cutter to engage a cylindrical surface of a crankpin upon manipulation of the adjusting screws, and springs separating said sections upon unthreading of the adjusting screws to move the cutter and seating plates away from said crankpin, said adjusting screws having graduations on heads thereof registrable with markings on the sections for spacing the sections to position the cutter with respect to said seating plates.

7. In a turning tool of the character described, a pair of mating arcuate sections, guide pins in opposite ends of the respective sections and slidably engageable in aligning bores in the facing ends of the sections, adjusting screws rotatably mounted in the sections and threadedly engaging the guide pins to mo've said sections toward each other, a cutter supported by one of the sections, seating plates supported in the other section and cooperating with the cutter to engage a cylindrical surface of a crankpin upon manipulation of the adjusting screws, a spring sleeved over each adjusting screw and having separating contact between a respective section and the guide pin carried by the other section whereby said sections are spread apart upon unthreading of the adjusting screws to move the cutter and seating plates away from said crankpin, and clamping screws for tightening the guide pins in said bores.

8. In a turning tool of the character described, a pair of mating arcuate sections, guide pins in opposite ends of the respective sections and slidably engageable in aligning bores in the op posite facing ends of the sections, adjusting screws rotatably mounted in the sections and threadedly engaging the guide pins to move said sections toward each other, springs urging said sections apart, a cutter supported by one of the sections, seating plates supported in the other section and cooperating with the cutter to engage a cylindrical surface of a crankpin upon manipulation of the Kadjusting screws, and clamping screws for clamping said guide pins in said bores.

9. In a device of the character described, a pair of sections having arcuate inner faces one of which is provided with a wedge shaped groove having one side face thereof substantially paral- 1e1 with a plane offset substantially 24 with respect toa plane passing through the axes of said arcuate faces, a cutter inserted in said groove and engaging one side thereof, a wedge block inserted in the groove between the cutter and the op'posite side thereof, screws for retaining the wedge block to anchor said cutter,

asias-ss and seating plates supported in the arcuate face of the other section and having plane faces respectively located substantially 90 apart and with one of said plates located at right angles to said oset plane.

10. In a turning tool, a pair of sections having arcuate inner faces, spaced adjustable guide screws connecting said sections with their axes parallel with a plane intersecting the axes of said arcuate faces, a cutter radially supported by one of the sections in a plane oifset substantially 24 with respect to a said plane, and4 seating plates supported in the arcuate face of the other section and having plane surfaces arranged at right angles to each other, said seating plates being located so that one of said plane surfaces is located at right angles to said oset plane.

11. A device of the character described including a pair of mating sections, means adjustably connecting the sections about a cylindrical object to be surfaced, a pair of seats on one of the sections to engage said object, a plunger in the other section cooperatingwith said seats to position the sections relatively tosaid object, said section having the plunger being provided with a cutter seat having a side. `face parallel with one of said seats and a bot-