US2306756A - Piston expanding apparatus - Google Patents

Description

. Dec. 29, 1942. D. RUBIN 2,306,756

I PISTON EXPANDING APPARATUS Original Filed Dec. 1, 1937 3 sheetksheetl 1 i mm Q m i m a KIIPLIJIIIIWP 0 Dec! 29, 1942. RUBlN 2,306,756

PISTON EXPANDING APPARATUS I Original Filed Dec. 1, 1937 S'Sheets-Sheet 2 un 1 llll H I I "K I m VENTOB David Tiub/n ArronA/Em Patented Dec. 29, 1942 PISTON EXPANDING APPARATUS David Rubin, Scranton, Pa., assignor to Scranton Industrial Development Company, Scranton, vPa., a corporation of Delaware Original application December 1, 1937, Serial No.

Divided and this application August 29, 1939, Serial No. 292,499

1 Claim.

This invention relates generally to devices for decreasing the clearance of pistons in the cylinders of internal combustion motors and more particularly to machines for expanding the pistons of such motors.

This application is a division of my application Serial'Number 177,569, filed" December 1, 1937, now Patent 2,174,217, dated September 26, 1939, and a continuation-in-part of my application Serial Number 118,964, filed January 4, 1937.

Internal combustion engines after a certain amount of use, lose compression and power owing to the fact that the piston rings, cylinder wall and piston skirt become worn down. The cylinder may be rebored and new rings and piston installed, but it ischeaper to replace the worn rings with new ones and use the old piston. The old piston, because of its relatively reduced-diameter, oscillates about the piston pin and between the cylinder walls giving rise to what is known as "piston slap. It is well known to insert a resilient expansive device within the piston skirt to enlarge the same, but this is unsatisfactory for many reasons, including the facts that insufflcient enlargement is obtained and the characteristics of the piston are altered.

Inasmuch as the new piston rings provide increased compression, 1 have found that if the piston skirt is expanded transversely of the piston pin, piston slap is removed and oil consumption is considerably reduced. I have also found that if instead of being expanded, the piston skirt is ovalized (a reduction of the skirt diameter, longitudinally of the piston pin and a corresponding increase in piston skirt diameter transversely of the pin) an improved motor f performance is obtained. Where the piston skirt is slotted a combination of expanding and ovalizing is very satisfactory.

.While it has been proposed-to expand piston skirts byhammering or peening them to an expanded shape, this has been unsatisfactory in that insuflicient expansion is produced and the peening causes the metal to crystallize and become brittle.

The present invention contemplates the physi cal expansion of the piston skirt while the same is in a heated and annealed condition. After the stretching operation is completed, the piston is retempered so that its original metallic condition is restored but the new shape is retained. The metal heating and treatment varies with the metallic composition of the piston.

ure 1;

tons, such method involving certain steps of heating, stretching, and cooling. The invention disclosed and claimed in the'present application relates more especially to apparatus for expanding pistons, e. g., in accordance with the method disclosed in my aforementioned patent. It will be understood, however, that apparatus embodying my present invention is not restricted in use to the practice of the particular method referred to.

The main object of the present invention is the provision of structure whereby a simple, efficient and inexpensive device accurately expands pistons of various types under close control.

Another object is to provide apparatus of the character referred to including a measuring device so correlatively arranged with respect to the piston forcing or expanding parts as to be conveniently movable to operating position and to be capable of indicating accurately the amount of expansion effected. v

Other objects will become apparent from a reading of the following description, the appended claim, and the accompanying drawings, in which:

Figure l is a fragmentary plan view of one preferred embodiment of the invention;

Figure 2 is a fragmentary elevational view of Figure 1;

Figure 3 is an enlarged fragmentary elevational view of the front of the machine shown in Fig- Figure 4 is an elevational front view of an alternate type of piston expanding peg;

Figure 5 is a sectional view of Figure 4 as seen from the plane 5-5 thereon;

Figure 6 is a bottom view of the moving piston peg shown on Figure 3 as seen from the plane 3-3 thereon;

Figure 7 is a top plan view of a further preferred embodimentgof the invention;

Figure 8 is a view in side elevation of the embodiment shown in Figure 7;

Figure 9 is a longitudinal vertical sectional view taken on the line 9-9 of Figure 7;

' Figure 10 is a vertical cross sectional view taken on the line Ill-l0 of Figure 7; and

Figure 11 is a detail perspective view of a piston-engaging abutment.

Form shown in Figures 1 to 6 inclusive l2 and I3 respectively and the side walls l4 and I5 may be sufficiently extended downwardly to enclose the heating and tempering ovens (not shown) for treating the pistons before and after stretching.

The stretching or expanding assembly, generally indicated by numeral I6, is composed essentially of a stationary arm l1 and a moving arm or carrier l8 upon which are detachably mounted a stationary piston expansion abutment or peg I9 and a movable piston expansion abutment or peg 20, respectively. tationary arm I1 is of rigid construction and is securely mounted, by means of two bolts 2|, to the bottom surface of top I and projects horizontally forward through the left end of a horizontally disposed oblong orifice 22 in front wall |2. Moving arm I8 is the load arm of a long lever or carrier 24 mounted similarly to arm H, but is pivotally connected to top H by means of bolt 23 which threadedly engages the underside of said top similarly to bolts 2|. The rear end of lever 24 has a nut 25 pivotally attached thereto, and the nut in turn is threadedly mounted on a transversely mounted screw 26. Screw 28 is trunnioned in side walls l4 and I5 and penetrates the latter to have a large hand wheel 21 affixed to the terminal thereof. Sufficient clearance 28 is provided, longitudinally with respect to lever 24, to allow for the arcuate travel of the rear end of said lever, so that the manual actuation of hand wheel 21 will result in the arm I8 and peg 20 slowly and powerfully approaching or receding from arm l1 and peg 29, depending upon the direction of rotation of the hand wheel.

It is, of course, apparent that other means of actuation of arm US may be employed, such as hydraulic, or compound lever means, but the means described above have been found efficient and inexpensive.

The abutments or pegs l9 and 20 may be identical in construction and interchangeable; hence a description of peg l9 will sufiice for both. The

posed slot. The face 65 is adapted to fit between the said vertical ribs or to distribute pressure over a sufficiently large area around the diagonal slot so that the skirt is not fractured. The curvature of face 65 may be altered to coincide with the configuration of different pistons, where advisable. Peg 62 is provided with a shank 60 which is inserted in the opening in the forward end of arm l8 and is secured with the nut 6|. Pivot head 64' prevents the head 63 from slipping off while shoulder 64 provides a smooth bearing surface in place of the upper face of arm l8, so that the head 63 may readily rotate.

A clamping device 29 is used to hold the piston to the stationary peg l9 before and after the piston is acted on by peg so that the piston will not become displaced and in order that accurate I measurements may be made before, during, and

working face 55 is plane, vertical, and trans,

versely disposed with relation to the principal direction of motion of peg 20. Face 55 is provided with a horizontal rabbet 56 at the lower edge thereof, and a horizontal groove 51. The purpose of these depressions is to permit horizontally disposed reinforcing ribs on the internal surfaces of the piston skirt to fit therein so that the expanding pressure maybe exerted against the relatively smooth portions of the cylindrical inner walls of the piston skirt. The placement of these depressions may be varied to suit the individual requirements of different types of pistons but the configuration shown in Figure 3 has been found satisfactory for nearly all ordinary pistons. The inner face 58 is provided with a deep rabbet 59, preferably curved at 59 so that the strain is evenly distributed and the likelihood of breakage is reduced. An integral shank fill threaded adjacent the end thereof, penetrates a vertically disposed orifice in arm iii and a nut 6| when tightened down securely clamps the peg L9 in place. Peg 20 is similarly attached to the arm I8.

In Figures 4 and 5 there is illustrated an alternate type of 63 which isadapted and the working face to swivel about the pivot 64 65 has a cylindrically shaped surface. The peg 62 is substituted in place of peg 20 when the piston skirt is of a type having vertically disposed reinforcing ribs, or when the piston skirt is provided with a diagonally dispeg. This peg 62 has a working head after the stretching or expanding operation. This device 29 comprises a support arm 30, and a clamping face plate3l. Since the piston is comparatively light and the pegs I9 and 20 maintain it in place while the piston is being expanded, the clamping device need notexert very great pressure. The face plate 3| is supported by an integral rod 32 perpendicularly projecting from the rear thereof to penetrate'the forward end of Support arm 30, and terminate in the operating knob 33. A spiral expansive spring 34 serves to force the face plate 3| against the piston skirt and clamp it against peg I9. The support arm 30 is adjustablyclamped at the rear end thereof to arm l1 by means of the thumb-screw 35. The forward portion of arm 30 is offset so that a sufficient clearance is provided for the insertion of the piston .skirt and the operation of the face plate 3L A measuring device 36 is provided for readily and accurately determining the amount of expansion given the piston skirt. Such a device orifice in the forward end of arm 4| and is adjustably clamped by a thumb-nut 43; and the lower one of which penetrates an orifice in the rear end of arm 44 and is adjustably clamped by a thumb-nut 45. The forward end of arm 44 is adjustably and pivotally connected to the, micrometer by the integral threaded shank 46 depending from said micrometer which penetrates said arm and is clamped by thumb-nut 41. Wherever desirable, the spacer 42 may be made adjustable, or other suitable mechanism may be utilized for varying the effective height of the micrometer.

An adjustable work table 48 is vertically regulable for supporting pistons of different heights and is pivotally mounted in a horizontal plane so that it may be swung into and out of position as needed. The horizontal face 49 is supported by an integral vertical post 50 which is in turn clamped in the bifurcated end of an arm 5|, the rear end of which is pivotally mounted on an inverted L shaped bracket 52 aflixed to the front wall l2. Actuation of thumb-screw 53 allows ad-z justment in a horizontal plane and actuation of of the alignment of the piston-engaging surfaces of the pegs may be made by operation of either one or both of the screws 9 and 120% I These adJustmentsare particularly convenient and important when the apparatus is used for expanding pistons of various designs.- I have found that the inner surfaces of the skirts of different types and makes of pistons taper axially of the pistons to varying degrees. The adjustments provided as described above make it possible to expand various kinds of pistons without providing special abutments for each particular design of piston.

In accordance with the invention, the embodiment disclosed in Figures 7 to ll inclusive also is provided with an indicator gauge or the like for measuring or indicating the amount of stretching or expansion of the piston being worked upon. As shown. a dial gauge III having a feeler I2! is mounted upon a screw I22 having threaded engagement with a bracket I23 l secured to the frame by means of a screw Ill.

A lock nut I25 on the screw I24 serves to clamp the bracket I 23 in adjusted position, and a lock nut I26 on the screw I22 serves to clamp the screw and hence the gauge in adjusted position with respect to the bracket. The gauge body thus is so mounted as to be adjustable relative to the frame. In use, the gauge is adjusted or moved to such position'that the feeler l2! engages the outer surface of a piston skirt prior to expanding thereof. Then the screw H3 is rotated to move the cross,headto the right so as to eflect relative separating movement of the abutments and stretching of thepiston until the gauge indicates that the predetermined desired amount of stretching has taken place.

Operation (of the form shown in Figures 7 to 11 inclusive) movable arm,

is to operate the screw 8 so asto move the cross head and abutment peg l2. :toward the left untilthe distance between the outer faces of the pegs It! and MI is considerably less than the inside diameter of the piston skirt. The piston: is then placed over the pegs, and, if it is found that the outer faces of the D88 Portions lleaand mi 'do notalign with the associated inner piston skirt portions, the necessary adjustments of one or both of the pegs. are effected in the manner already described. The gauge is then set so that the 'feeler l2" engages the outer surface of the piston. and the screw is rotated in the opposite direction until the gauge shows that the proper amount of stretching has taken place. Thereafter the screw is again rotated to move the cross head to the left so that the. piston may be removed from the apparatus.

The apparatus shown herein embody the invention in preferred and commercially successful forms, but it is to be understood that. changes may be made without departing from the invention as defined in the claim.

I claim: d A piston skirt expanding machine including a stationary casing; an arm fixedly attached to said casing; a movable arm attached to said casing and adapted for movement toward and away from said stationary am, saidmovement being rectilinear in at least one plane; a pair of pegs for coal-B n! he inside surface of a piston skirt, said pegs being-mounted one on each arm; and a measuring device having a feeler movable in substantially the same direction as the said device being adjustably mounted on said casing whereby the same may be rigidly positioned. so that the feeler may contest the outside of said piston skirt adjacent the peg of the movable arm, and register the amount of movement in said skirt portion in said plane, caused by the peg on the movable arm.

DAVID RUBIN.

Images