Dec. 17. 1946. 2,412,885 R. M. HARMON SHOCK ABSORBER Filed Oct. 14, 1944 /0 / l/lll/l/ INVENTOR. ?lm/V. ?qnwaw BY nrrolwvsr' Patented Dec. 17, 1946 2,412,885 UNITED STATES PATENT OFFICE 2,412,885 SHOCK ABSORBER Ralph M. Harmon, Wichita, Kane, asslgnor to Beech Aircraft Corporation, Wichita, Kane, a corporation of Delaware Application October 14, 1944, Serial No. 558,155 2 Claims. (01. 188-88) ‘ l 2 The invention here disclosed relates to shock absorbers. and particularly to shock absorbers of the type employed in aircraft landing gear. Objects of the invention are to provide shock absorbing mechanism of strong but light weight cated at the outer end of the barrel and a second bearing land 8 is provided at an intermediate point, slightly beyond mid-length of the cylinder. construction and arranged to effectively carry the bending stresses to which such devices are sub by welding, brazing, soldering, riveting, bolting or iected. screw fastening. ‘Other objects of the invention are to simplify and reduce the cost of manufacture and assem bly. Other desirable objects and the novel features by which the purposes of the invention are at These spaced bearing lands may be integral portions of the cylinder or they may be separately formed and then integrated with the cylinder as In the illustration the outer or end bearing land 10 is indicated as having a screwed connection at 9 in the end of the cylinder and the intermediate bearing land is shown as secured at a selected in termediate position in the cylinder by screw fas tenings Ill. of the following speci?cation. This construction, with the piston of smaller 15 The drawing accompanying and forming part diameter and free and clear of the inner surface tained are set forth or will appear in the course of the speci?cation illustrates a‘present practical oi’v the barrel and the only engagement between the barrel and piston taken by interposed bearing embodiment of the invention. Structure, how ever, may be modi?ed and changed as regards lands eliminates need for precision machine work the present disclosure, all within the true intent 20 and time consuming ?nishing operations on the inner surface of the barrel. As the piston en and broad scope ‘of the invention as hereinafter gages only the inner surfaces of the two bearing ie?ned and claimed. The single ?gure in the drawing is a longitudi elements ‘I, ll, only the inner surfaces of these 18.1 sectional view of a present commercial em members need be accurately ?nished, such as to aodiment of the invention. 25 the extent of honing and polishing, to match the ?nish of the piston. In this view the barrel or cylinder is designated I and the tubular piston operating therein, 2. Where as is usually preferred, the bearing lands 1 and 8 are separately formed ring elements, these can be readily machined at reasonable cost, sep~ :ively movable parts of the aircraft landing gear 30 arate and apart from the barrel and then after proper ?nishing, be assembled and secured in their )1‘ other apparatus to which the mechanism is applied. proper positions in the barrel. The piston, be In the example, the closed end of the cylinder ing of the one continuous diameter, can be as sembled by simply passing it through the spaced :arries a ?tting 3 perforated to receive a mount ng bolt, and similarly the closed end or the pis 35 outer and inner bearings of the cylinder, and dis assembly can be as readily accomplished, in re aon carries a ?tting 4 perforated for reception of The outer or closed ends of these parts are sult ibly equipped for attachment between the rela a. bolt or other fastening. The inner end of the piston carries a cap or ring 5 open at the center at 8 for passage of air ll'ld oil or other mediums that may be employed is the cushioning and shock absorbing materials. The external surface of the tubular piston is :moothly. ?nished, usually centerless ground and )OIiShBd, and in the structure shown the piston verse manner. The piston is shown as having an attachment II for ?lling and emptying and a packing is con ventionally indicated at H in the outer bearing land, it being appreciated that these may be of any standard or acceptable designs and located in either or both of the aforementioned lands. The novel construction disclosed enables ac s of the same, single diameter its full length. 45 curate calculation of bending stresses in the piston and ef?ciency in a strength-weight ratio. Little inishing operations on the piston. or no internal machining in the cylinder is re The piston, instead of having a sliding engage quired. The bearing‘lands can be made up as pre nent its full length in the cylinder or having a finished rings and be inserted and mechanically mad in sliding engagement in the cylinder, is 50 secured in proper position in the barrel at much ilidingly guided and supported by special bearing less cost and with more efficient operation than this enables simple, inexpensive machining and ands poistioned and proportioned to best carry could be accomplished with internal boring and .he loads and stresses to which the parts are sub honing operations on the barrel. The screw mounting of the bearing lands illustrated enables In the illustration, one bearing land ‘I is 10- 55 ready removal and replacement of these parts if ected. ' 2,412,885 3 they should become worn or injured. 4 This re placeability of the inner, intermediately located bearing is of advantage also to provide for re placement of such a bearing land with one of , supported and spaced bearing lands, whereby the only bearing surfaces are the external surface of the piston and the internal surfaces of said ?xedly spaced lands. greater or less width or located in a different in termediate position for taking care of different bearing loads or other variables. 2. In a shock absorber or hydraulic actuator for aircraft or the like, an arrangement comprising a claims shouldbe read accordingly. I claim: tained liquid and air, said piston having external barrel having open and closed ends and external While of particular importance for shock struts attaching means at the closed end, a tubular pis and other forms of shock absorber constructions, ton having open and closed ends and operating it will be realized that the invention is adapted to 10 with the open end within the open end of the other purposes, such as to hydraulic actuators for barrel and forming therewith a variable capacity aircraft and the like. The speci?cation and compression ‘and expansion chamber for con attaching means at the closed end or the same, 1. In a shock absorber or hydraulic actuator for 15 said piston being of less diameter and operating aircraft of the like, an arrangement comprising a clear of the inner surface of the barrel and hear barrel having open and closed ends and external ing lands for the piston ?xedly secured in said attaching means at the closed end, a tubular barrel at the outer, open end and at an inter piston having open and‘ closed ends and operating mediate point in the length of the barrel, said with the open end within the open end of the bar 20 bearing lands having smooth ?nished internal rel and forming therewith a variable capacity bearing surfaces of fundamentally the same di compression and expansion chamber for con ameter and of less diameter than the internal di tained liquid and air, said piston having external ameter of the barrel and the tubular piston hav attaching means at the closed end of the same, ing a corresponding smooth ?nished bearing sur said piston being of less diameter and operating face of the same diameter and slidingly operating clear of the inner surface of the barrel and bear in said ?nished internal surfaces of said ?xedly ing lands for the piston ?xedly secured in said supported and spaced bearing lands, whereby the barrel at the outer, open end and'at an inter only bearing surfaces are the external surface of mediate point in the length of the barrel, said the piston and the internal surfaces of said ?xedly bearing lands having smooth ?nished internal 30 spaced lands, said intermediate bearing land be bearing surfaces of fundamentally the same die ing a pre?nished ring of a size insertable in the ameter and of less diameter than the internal di barrel and said ring being inserted to a selected meter of the barrel and the tubular piston hav intermediate position in the barrel, and means se ing a corresponding smooth finished bearing sur- , curing said pre?nished inserted ring ?xed to said face of the same diameter and slidingly operating 35 barrel in said selected position. in said ?nished internal surfaces 0! said ?xedly RALPH M. HARMON.