US1921643A - Piston - Google Patents

Description

M. o1 TEL-:TOR

Aug. 8, 1933.

PISTON Filed Jan. 24. `19,31

v2925/6722707 Mey N-507 MMM,

Patented Aug. 8, 1933 UNITED- STATES.

Prs'roN Macy 0. Teetor, Newcastle,` Ind., assigner to The Perfect Circle Company, l a Corporation of Indiana application,.mummy24, 1931. slrialNasio-,soo

' sciaimsgicigsos-fii) and temperature ranges of the engine without riskof seizing orbinding or of undue wear taking place at any point of thepiston or cylinder, while at the same time7"blow-`by, oil pumping and piston slap'are substantially eliminated.` Another object of the invention `is to provide a piston which will accomplish the above while atthe same time it will be simple in design, easily cast and cheap to manufacture. "l vThese and further objects of my invention will appear from the following specication,`-refer` ing taken on the line 3-3 of Fig. 2; and

Fig. 4 is a cross section taken on the line 4 4 oi' Fig. 1.

My improved piston, which is made of metal having a lower specific gravity than iron, such as an aluminum alloy, includes a skirt 8 and a head 5, the latter being provided with grooves for receiving piston rings. A circumferential slot 'I separates the top` oi' the skirt.i'rom lthe depending wall of the head. The skirt is provided with a vertical slot 8 which extends from end to end of the skirt.

The head and skirt are connected together interiorly by two parallel struts 9 which carry the piston pin bosses 10, projecting in opposite directions and in alignment with enlarged openings ll in the skirt. Each strut 9, which ls cast integrally with the head and skirt has the general form of an inverted T and includes-a vertical arm 12 depending from the top oi' the piston, a laterally projecting arm 13 integrally connected to the skirt opposite the'slot 8, and an oppositely extending arm 14 integrally united at its outer end to one edge of a vertical web 15 carried by the skirt, there being two aligned webs 15, one for latter.

each strut` The larms 13a d 14 `cor`1stii'.ute,"in effect, cross members.' -1 j The webs 15 are integrally united at thei-rupper and llower endsyrespectively' to v'circular lribs 17 and 18 onthe'iskirt. l-When thepiston isfflrst cast, the webs `15 'form anfundivid'ed piece, but when the slot vil iscut'into 'the skirttheslot 119 between the webs is v cut by the` sametool t'o` form the two'disconnected webs.

It will be yobserved thatthe 'arms 12"of the 5 struts -are spaced from -the`dependin`g circular wall of the head, that the arms 14?;ar`enarrow (vertically) "and connected to" theflongi vertical webs l5, intermediate `the upperfand lowerends ofthe latter, that the bosses-f110Vareindependent of `the skirt andithat the armsl` arev relatively wider and' hence less vflexiblelaterally lthan the arms 14. The arms13 are preferably not joined directly to the circular ribs l7- and 18 on th'eskirt. In operation, the head of the piston is always at a higher temperature than the skirt but, due to the circumferential slot 7 between the head and skirt, the former may expand more than` the The larger portion of the heat in the head is conducted directly through the piston rings to the water jacketed walls oi the cylinder, but acertain portion of this heat flows downward through the exible struts 9 to the wrist pin bosses 10 and the skirt.' The rise in temperature of the skirt tends to cause a radial expansion of the same, but owing to the vertical slot 8 in the skirt it may yield circumferentially to accommodate itself to the cylinder. The expansion of the head on the diameter in the plane of theslot 8` (i. e.,.the plane on which Fig. 1 is taken) does not tend to distort the skirt. However, expansion on the diameter at right angles to the slot 8 (i. e. in the plane of the cross section of Fig. 2) moves the upper ends of the struts 9 apart, and this movement would `distort the skirt if the struts 9 were not flexible to permit themto bend slightly and thus accommodate this movement of the upper ends of the struts. It will also be observed that as the slot 8 closes when the metal of the skirtv expands, this movement is permitted by the ilexibility of the arms 13 and 14..` The webs are arranged at right anglesto the struts and the arms 14 of the struts are united to the webs at the outer edges (i. e., the edges opposite the slot 19) of thewebs and intermediate 105 the upper and lower ends of the latter. Due to this arrangement, when the arms 1 3 and 14 expand in the direction o i their length croswise o1' the piston, the vertical webs bend between their upper and lower ends andprobably twist 11 slightly out of their plane, so that the expansion of these arms is not transmitted to the skirt. Were the angular relation between each web and strut greater than 90, then when the arms 13 and 14 expanded lengthwise they would exert a component force on the web in the plane of the latter and tend to distort the skirt. This distorttion would be aggravated further by the tendency of the web to expand widthwise in its plane due to the increase in temperature.

It will now be apparent that a piston embodying my invention is admirably adapted to accomplish the objects first above stated. The expansion of the head will not distort the skirt, which is permitted to maintain a close working fit throughout its circumference with thecylinder'` at all temperatures and speeds Without risk of sticking or undue wear taking place at any point of the piston or cylinder. Blow-by, oil pump'- ing and piston slap are practically eliminated. The piston is simple in design, easily cast and may be finished at a low cost.

I claim: k y

1. In a piston of the class described, a skirt and a head with a circumscribing slot between the same, the skirt havingy a longitudinal slot, vertical webs connected yto saidskirt only at their upper and lower ends, and flexible struts depending from said head and each includngla laterally projecting arm connected at its outer end to one edge of its'respective web and forminga right angle with the web.

2. In a piston of the class described, a skirt andra head with a circuxnscribing slot between thevsame, the skirt having a longitudinal slot, vertical webs adjacent either side of said longitudinal slotl and connected to the skirt only at their upper and lower ends, and flexible struts depending from the head and connected to said webs intermediate the ends of the latter, the webs being flexible and arranged at right angles to the struts.

3. In a piston of the -class described, a skirt and a head with a circumscribing slot between the same, the skirt having a longitudinal slot. vertical webs immediately adjacent either side of said longitudinal slot and connected to said skirt only at their upper and lower ends, flexible struts depending from said head and connected to the side of the skirt opposite said longitudinal slot and also connected to said flexible webs.

4. In a piston of the class described, a skirt and a head with a circumscribing slot between the same, the skirt being provided with a longitudinal slot, ilexble members carried by said skirt adjacent said longitudinal slot and separated by acoinciding slot, and struts depending from said head and connected to said flexible members andA to the opposite side of the piston.

5. In a piston of the class described, a skirt and a head, the skirt and head being separated by a circumferential slot, struts depending from said head and carrying the piston pin bosses independently of the skirt, adjacent flexible vertical webs, each connected only at its upper` and lower ends to one side of the skirt, arms connecting only the central portions of said vertical webs to said struts, and arms directly connecting the other side of the skirt to said struts.

6. In a piston of the class described a skirt and a head, the skirt and headbeing separated by a circumferential slot, struts depending from said head, adjacent vertical webs arranged at right angles to said struts and each web connected only at its upper and lower ends to said skirt, and arms connected only to the central portions of said webs and to said struts. .l

MACY O. TEETOR.

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