US2693708A - Lever system - Google Patents

Description

Nov. 9, 1954 w. s. BAER, SR., ET AL LEVER SYSTEM 5 Sheets-Sheet l Filed Sept. 30, 1952 YUM. u NWSeN m EE:

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LEVER SYSTEM Filed Sept. 30, 1952 3 Sheets-Sheet 2 :mim

NOV 9, 1954 w. s, BAER, SR., ETAL LEVER SYSTEM 3 Sheets-Sheet 3 Filed Sept. 30, 1952 .6 mmf, WZ lim, U E 5 Mm W LEVER SYSTEM Walter S. Baer, Sr. and Max W. Baer, Yeadon, Pa. Application September 30, 1952, Serial No. 312,423

4 Claims. (Cl. 74110) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The invention relates to a lever ,system and more particularly to a lever system which is adapted to be used .in conjunction with an airplane arresting gear on anV a1rcraft carrier.

When an airplane comes in for a `landing on the deck of a carrier it must be brought to a stop after a relatively short run since, otherwise, its original momentum would carry it over the side of the ship. For this purpose, a hook is carried on the plane which is engaged by a cable when the plane comes in for a landing. This cable is connected to the arresting mechanism The cable pulls a piston or ram through a tube .or cylinder arranged below the deck. This cylinder contains a fluid ahead of the ram and as the ram is driven forward it compresses the lluid which is then forced into a constant pressure valve chamber. The constant pressure 'control valve comprises an oriced sleeve on a stem. The liuid under pressure impinges against the end of the stem, which projects out of the valve chamber, and pushes the valve forward. This movement causes the orifices in the sleeve to mate with corresponding orifices in the valve chamber wall and allows some of the pressure fluid to meter through these orifices and through the adjacent chamber and check valve to an accumulator or storage tank. When a sutiicient amount of the pressure fluid is metered off in this way, the pressure against the valve stem is lessened. There tact with the other end of the valve stem, and this force acts to return the valve toward its original position when the pressure of the liuid from the rm cylinder is suiiiciently relieved. This counter-acting force is here illustrated as an oil piston which slides in an oil cylinder and in turn is acted upon by a constant air pressure from separate air-oil flask, or dome, that has an air volume 25 times the oil piston displacement for steadiness of pressure. The force transmitting means between the valve stem and the piston takes the form of a lever system, and it is this lever system which forms the basis of this invention.

The invention generally comprises a series of separate pivoted levers which extend between the valve stem ,and the counterbalancing force. Each of these levers acts either directly or indirectly on another lever to transmit the force from one direction or the other.

The central lever in the system is mounted for longitudinal adjustment between the adjacent levers on either side so as to vary the amount of pressure thrust between these adjacent levers. This centralV lever is adjusted to a predetermined position depending on the pressure which is expected to be applied on the valve stern by the liuid coming from the ram cylinder. The angular travel of the aforesaid adjacent levers is kept at a minimum kfor all pressures of the ram fluid by utilization .of the midcycle reversible levers hereinafter described, and there are, as a consequence, no sideward thrust forces on the oil piston and attached parts but instead,

priate setting of the central lever, the entire acting forces created by the ram cylinder pressure through the valvel stem exert their energy only in a direction perfectly parallel with the center lines of the oil piston `and the sleeve valve.

One object of this invention is to eliminate or minimine the varying pressure .eieet on ra constant pressure 1s a counteracting force in conat the appro- Y States Patent O d 2,693,708 Patented Nov. 9, 1954 ICC valve counter-.balancing means, `which is due to the varying angular travel of the levers connecting the valve to the counterbalancing means.

Another object of this invention is to provide a lever system that will enable the constant pressure valve of an airplane arresting gear to provide a steady pressure reduction of the ram cylinder fluid throughout the working stroke of the ram, thereby producing as nearly perfect an indicator pressure curve as is mechanically feasible, and causing an even deceleration in the speed of the arrested aeroplane on the Hight deck.

Another object of this invention is to provide a lever system that is of Vmuch than those used previously.

Other objects and many of lthe attendant advantages of this invention will be readily appreciated as the saine becomes better understood by reference to the following detailed description when considered in connection with the accompanying .drawings wherein:

ig. 1 is a view partly in section and partly in elevation showing the lever system in battery position, that is, with no pressure on the valve stem and with the oil piston head Vunder valve closing pressure.

Fig. 2 is a side elevational View of the lever housing.

Fig. 3 is a perspective view showing the lever elements -in relation to each other.

Fig. 4 is a top plan view of the bearing means on the valve stem showing their relation to the lfront levers.

Fig. 5 is an elevational view of the central ratio adjusting lever.

Fig. 6 is a view partly in section and partly in elevation taken on line 6-6 of Fig. 1.

Fig. 7 is an enlarged detailed view ofthe micrometer adjusting means for the central lever.

Referring now in detail to the drawings wherein similar reference characters refer to similar parts, there is shown a lever housing 10 which is constructed in two sections consisting of upper .section 12 and lower section 14. A plurality of bosses 16 .are cast integrally with the section 12 and a like number of bosses 18 are cast integrally with section 14. An VAllen head screw 20 connects each of the bosses 16 to its complementary boss 18.

The housing 10 is open 4at each end and each of these open ends is provided with a peripheral liange as indicated at 21 and 22. The open end 21 is adapted to be closed by a closure member 24. Drilled holes 26 in the ange 21 are adapted to mate with drilled holes 28 in the closure member 24. Bolts 30 pass through the mating holes 26 and 28 and are locked in position by nuts 32. A central opening 34 in the closure member 24 is adapted to receive the member 36 shown in outline. The member 36 is a closure for the valve housing, not shown. Bolts 35 extend through openings in the member 36 and are screwed into tapped holes 37 in member 24, thereby connecting the member 36 to the member 24.

The valve stem 38 projects from the valve housing 36 into the lever housing 10 as illustrated in Fig. 1, and threaded on the end of the vvalve stem is a pin there are mounted a is held in position by a cotter pm 49 bent through a hole 51 in 12 of the housing is a pair of ears 54 integral with the housing, a bushing 56 and a pin 58. A cotter pin and washer, not shown, hold the pin in place. Pivotally mounted in Vthis bearing is a lever 60. The lever 60 comprises a bent arm 62 and a off-set portion consisting of a pair of ears 64 between which a roller 66 is mounted on a bushing 70. A pin 68 holds the bushing in place. A Cotter pin and washer, not shown, hold the pin in place. A similar lever assembly extends from the bottom section 14 of the housing and the similar parts are identified as 52', 54', 56', 58', 60', 62', 64', 667, 6,8' and 70.

The ends of the lever arms 62 and 62' overlap each other in a horizontal plane as seen in Figs. 1 .and 3, and these overlapping portions bear against the ferrules .on the yoke 40. The rollers `66 and 66 mounted in the offsmaller size and lighter weight yoke 40 having7 legs 42 and 44. A pin 46 extends through openings inVY set portions of the levers 60 and 60' meanwhile bear against a bar 72.

The bar 72 extends across the full width of the interior of housing and is provided at each end with a roller 74 which is rotatably mounted on a bushing 78 through which extends a pin 76. A cotter pinand washer, not shown, hold the pin inV place. These rollers 74 are adapted to move in grooves 80 which are provided in the top and bottom sections of the housing. The bar 72 Vis also provided with a centrally located bearing surface 82 made of cobalt or the like, this surface being located on that side of the bar which is remote from the levers 60 and 60'. The surface 82 bears against a roller 84 mounted on a pivoted lever 86.

The lever 86 is pivotally mounted on a bushing 90 which is held between the ears 92 by a pin 88. A cotter pin and washer, not shown, hold the pin in place. The ears 92 are made integral with the upper housing section 12. The aforementioned roller 84 is mounted on one face'of the lever 86 while on the opposite face of the lever is provided a bearing surface 94 made of cobalt or the like.

Opposite to and spaced from the lever 86 is a lever 96, illustrated in Figs. l and 3. This lever 96 is pivotally mounted between the ears 102 on a bushing 100 through which extends a pin 98. A cotter pin and washer, not shown, hold the pin in place. The ears 102 extend from and are integral with the bottom housing section 14. A bearing surface 106 is provided on the opposite face of the lever. Both of these bearing surfaces are made of cobalt or the like.

Extending between the pivoted levers 86 and 96 is the central or ratio adjusting lever 108. The lever 108 consists of a yoke portion 110 from which depends a guide rod 112 which extends through a guide slot 113 in the housing. A pair of bushings 114 are positioned in the yoke in side-byside relation, each by a pin 116 which passes through the bushing. A washer 118 holds each pin in place and is locked in position by a cotter pin 120 which is bent through a hole 122 in the pin 116. A pair of rollers 124 are rotatable by the bushing and pins within the yoke. Preferably these rollers are in line contact with one another as well as the adjacent links 86 and 96. The yoke is, in turn, pivotally mounted on the end of a partially threaded shaft 126 by means of a pin 128 which connects the ears 130 of the yoke to the shaft. A washer 132 holds the pin in place and a cotter pin 134 bent through a hole 136 in the pin 128 holds the washer in place.

The partially threaded shaft 126 extends through a housing 138 which is separable from the main lever housing 10 but which is connected to the section 12 of that housing by means of screws 140 which pass through a flange 142 on the housing 138. A wall 144 separates the interior of the housing 138 from the interior of the housing 10. Perforations 146 in the wall are provided for lightening purposes. The top of the housing 138 is closed by a cap 148 by means of screws 150 which screw into ange 152 of the housing 138 and pass through ilange 154 of the cap 148. In the housing 138 there is a boss 156 in the wall having a recess 158.

The top of the housing 138 is provided with a central opening 160 and through this opening depends a boss 162 integral with the cap 148, this boss having a central recess 164. An internally threaded bushing 166 is held within the recesses 158 and 164 and is so arranged that the threaded shaft 126 extends therethrough. An opening 169 is provided in the housing 138 to allow a chain to extend into the housing from a control means, either manual or power driven, for the purpose of rotating the sprocket 168 on the bushing 166. A central bore 170 is formed in the cap 148 and an externally threaded hollow housing 172, integral with the cap and having an interior wall coincident with the bore 170, extends from the cap. An internally threaded ring 174 is vertically adjustable on the upper part of the housing 172. The housing 172 is further provided with a pair of oppositely disposed vertical slots 178 and a vertically positioned plate having a micrometer scale 180. The slots and the plate interrupt the screw threads on the exterior of the housing. Attached to the upper portion of the shaft 126 is an indicator bar 182. The bar 182 is loosely held on the shaft 126 and extends through the slots 178, so that when the shaft is moved vertically within the housing the bar will also move vertically but will be prevented from roller 188 which is mounted on a bushing 190 held within a yoke 192 by a pin 194. The pin 194 is secured by a washer 196 and by a cotter pin 198 bent through a hole in pin 194. The yoke 192 is integral with a hollow piston 200 which is provided with a flanged piston 4head 202 at one end. The hollow piston slides in an oil cylinder 204. An O-ring 206, set in groove 208 in the piston head, is used for the purpose of providing a sealing means between the piston and the cylinder wall. An inlet pipe 210 leadsfrom, a constant pressure air dome 211 to the interior of the oil cylinder behind the piston head. Another pipe 212 leads from the same air dome to a chamber 214 formed in front of the piston head. The uid in the chamber 214 serves as a dashpot during the counterbalancing movement of the pistou within the oil cylinder. A drain opening 216 closed by a stop-cock 218 is provided in the oil cylinder behind the piston head.

The oil cylinder, itself, is composed of two sections 220 and 222, the sections being bolted together by bolts 224 passing through drilled holes 226 and 228 and se cured by nuts 230.

In the front end of the section 220 of the oil cylinder are provided a pair of oppositely disposed guide slots 232 and in these slots ride the ends of a guide bar 234 which passes laterally through the piston 200. The slots 232 act as key-ways and the bar acts as a key to keep the piston from rotating.

Behind and slightly spaced from the slots 232 in the oil cylinder an annular groove 236 is located and in this groove are provided a plurality of V-rings 237 set between a follower and an adapter. A gland ring 238 holds the V-packing in place and a ring 240 holds the ring in position. An O-ring 242 is set in a recess 244 formed in the ring 240.

The oil cylinder section 220 is flanged at 221 to provide a closure member for the opened end of the lever housing opposite to the thrust member 38. Bolts 246 passing through drilled holes 248 and 250 and cooperating nuts 252 serve to secure the end closure to the lever housing. The operation of the lever system is as follows:

During the working stroke of the ram in the ram cylinder of the arresting engine, pressure is brought to bear on the end of the valve stem. When this pressure exceeds the resistance oifered by the oil piston, acting through the lever system, the valve stem moves to the left as illustrated in Fig. 1.

The lever system is so arranged that by merely varying the position of the central ratio adjusting lever 108, a mechanical efficiency ratio varying from one to one to four to one can be attained between the valve stem and the pressure-actuated oil piston.

When the lightest type of airplane is arrested, the ram cylinder pressure is comparatively low. The ratio determined for this type of airplane is one to one. This means that the central lever is adjusted to the correct position wherein the rollers 124 are on the axis which runs through the center of the valve stem and through the center of the oil piston as illustrated in Fig. l. With this one to one ratio there would be no angular travel of the levers 86 and 96.

When the heaviest airplane is arrested. the ram cylinder pressure is comparatively high. The ratio determined for this type of airplane is four to one. To obtain this ratio, the central lever 108 is moved to the position where the indicator pin 184 points to 4 on the micrometer scale. In this case, the actual travel of the valve stem under pressure from the ram cylinder is 5/6 inch, the bar 72 travels only 0.0586 inch and the ends of the levers 86 and 96 angularly travel only 0.1172 inch. This slight travel is primarily due to the fact that the levers 60 and 60 are mid-cycle reversible levers. In other words, when the stern 38 moves under pressure from the ram cylinder, its force is taken up by the elongated bent arms 62 and 62' adjacent their free ends but transmitted to the lever system by the short olf-set portions adjacent their other ends. The free ends of the arms move a relatively greater distance toward the oil piston under pressure from the stem, while the offset portions are moved a much smaller distance under the same pressure and even, after a certain point, tend to move back toward the Valve while the free ends of the arms are still moving forward. This is because although both the free ends of the arms and the off-set portions have a rotary or rocking movement about the pivots 58 and 58', the arc described by each of the off-set portions is much smaller than the arc described by each of the arms. Since the transmitted force from the valve stem to the lever system acts through the offset portions bearing against the bar 72, only a short movement of the bar is affected, and this results in but slight movement in the remainder of the lever system. Since the pivots of the levers 86 and 96 are so located that in mid-travel the levers are perfectly vertical, the lever ends actually only move 0.0586 inch from the vertical at maximum travel in either direction. It is, therefore, seen that even for the heaviest airplane the angular travel of the levers 86 and 96 is negligible. The constantly varying pressure effect due to the angular travel of the levers used in older systems is, therefore, eliminated or minimized. There are no sideward thrust forces on the oil piston and its attached parts or on the levers and, therefore, at any setting of the levers, the entire acting forces created by the ram cylinder pressure acting through the valve stem, or by the air dome pressure acting through the oil piston, exert their energy only in a direction perfectly parallel with the common axis of the oil piston and valve stem.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A force transmitting system comprising a member which is periodically actuated from a first position to a second position; means for resisting movement of the said member from its first to its second position; a lever system operatively positioned between the member and the resisting means, said lever system including a pair of bell crank levers respectively pivotally disposed on opposite sides of the axis of displacement of the said member, the longer arms of the crank levers being arranged to overlap adjacent a point where they are operatively connected to the said member and the shorter arms of the crank levers being operatively connected to the said resisting means, said lever system further including means for adjustably controlling the magnitude of thrust transmitted through the system.

2. A force transmitting system comprising a housing; a shaft member which extends through an opening in one extremity of the housing and which is periodically displaced along its axis from a rst to a second position; means disposed adjacent the opposite extremity of the housing for resisting movement of the shaft member from its first to its second position; a pair of bell crank levers respectively secured on a pair of opposite sides of the housing and arranged such that the longer arms thereof overlap adjacent the center of the housing at a point where they are operatively connected to the shaft member; an elongated bar which extends between the said opposite sides of the housing across the interior thereof, the said bar being operatively connected to each of the shorter arms of the said bell crank levers and also to the said resisting means.

3. A force transmitting system comprising a housing; a shaft member which extends through an opening in one extremity of the housing and which is periodically displaced along its axis from a first to a second position; means disposed adjacent the opposite extremity of the housing for resisting movement of the shaft member from its first to its second position; a pair of bell crank levers respectively secured on a pair of opposite sides of the housing and arranged such that the longer arms thereof overlap adjacent the center of the housing at a point where they are operatively connected to the shaft member; an elongated bar which extends between the said opposite sides of the housing across the interior thereof, the said bar being operatively connected to each of the shorter arms of the said bell crank levers; and means operatively positioned between the said bar and the said resisting means for adjustably controlling the magnitude of thrust transmitted through the system.

4. A force transmitting system comprising a housing; a shaft member which extends through an opening in one extremity of the housing and which is periodically displaced along its axis from a first to a second position; means disposed adjacent the opposite extremity of the housing for resisting movement of the shaft member from its first to its second position; a pair of bell crank levers respectively secured on a pair of opposite sides of the housing and arranged such that the longer arms thereof overlap adjacent the center of the housing at a point Where they are operatively connected to the shaft member; an elongated bar which extends between the said opposite sides of the housing across the interior thereof, the said bar being operatively connected to each of the shorter arms of the said bell crank levers; a first lever member which is pivotally secured to one of the said opposite sides of the housing and which extends inwardly toward the interior of the housing Where it is operatively connected to the said bar; a second lever member which is pivotally secured to the other of the said opposite sides of the housing and which extends inwardly toward the interior of the housing where it is operatively connected to the said resisting means; and means operatively positioned between the said first and second lever members for adjustably controlling the magnitude of thrust transmitted through the system.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,087,885 Fleischel July 27, 1937 2,132,338 Ziebolz Oct. 4, 1938 2,222,551 Ziebolz et al Nov. 19, 1940 2,427,623 Rockwell Sept. 16, 1947 2,492,200 Stiegletz Dec. 27, 1949 2,539,913 Koepcke Jan. 30, 1951 2,598,674 Burgess June 3, 1952

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