USRE18411E - Shock absobbeb - Google Patents

Description

M. R. JENNEY SHOUK ABSORBER April 5, 1932.

lvg w Ressued Apr. '5, 1932 UNITED STA TES PATENT OFFICE uELvIN n. JENNEY, or MELROSEMASSA'CHUSETTS, ASSIGNOR, BY MESNE ASSIGN- MENTS, To THERMOSTATIC CONTROL COMPANY, or BOSTON, MASSACHUSETTS, A

CORPORATION OIF MASSACHUSETTS SHOCK -ABSORER riginal No. 1,686,381, dated October 2, 1928, Serial No. 42,534, filed July b, 1925. Application 'for reissue led December 17, 1931. Serial No. 581,766.

The present invention ,relates to Shock absorbing devices, and more particularly to apparatus of this character embodied in motor vehicles and designed to absorb shocks due to inequalities in the surface of the roadway.

Many .diii'erent types of shock absorbing devices have been designed for use in connection with'motor vehicles. In general these devices may be grouped in three classes, those which control the movement of the chassis, more particularly the rebound, through spring controlled check members, apparatus which controls the movement of the chassis through the use of an air controlled dash-pot or similar construction, and devices' which control movement of the chassis through a liquid impelled from one chamber to another by a piston. When the various factors entering into the eiticiency of such a construction are considered, more generally the cost of' manufacture and the results accomplished by the construction, it is probable that the liquid type of shock absorber ranks rst. This type of shock absorber, however, varies in its operation with differences in temperature, more particularly' the marked diierences which exist between the Summer and winter temperatures of the northern climate. I have discovered that this variation in the operation of the shock absorber is due to changes in the viscosity of the liquid and that this change in viscos1ty may be sufficiently great to seriously impair the eliciency of the Shock absorber with temperature differences of 400 F. or F.

Accordingly, one object of the present invention is to provide a new and improved type of liquid shock absorber which will operate withythe maximum efficiency and under Widely varying temperature conditions.

A further Object of the invention is to reorganize and improve shock absorbers of the liquid type in a manner to render such ab- Sorbeis more positive and effective in their action and. preclude the possibility of im` proper adjustment in the hands of the unskilled mechanic or user. f

W`th these and other objects in view, the

varousfeatures of the invention consist in certain novel features'of construction, combinations and arrangementsof parts hereinafter described and claimed, the advantages of which will be obvious to those skilled in the art from the following description.

- In the accompanying drawings illustrating the preferred form of the invention, Fig. l represents a sectional plan view of a well known type of shock absorber embodying the features of the .present invention; Fig. 2 is a detail illustrating a Section of the Shock vabsorber shown in Fig.v l; and Fig. 3 is a section in elevation of a different type of Shock absorber also embodying the features of the invention.

According to the present invention, the Shock incident to meeting with an inequality in a roadway is cushioned by the passage of liquid from one chamber to another through a relatively small orifice or opening. The size of this passage is adjusted in accordance with the weight of the vehicle and the character of the liquid employed in the shock absorbing device. Furthermore, having initially adjusted the passage in accordance with these factors in a manner to secure the best riding qualities, the area or` size of the orifice or passage is thereafter controlled automatically and varied in accordance with variations inA the temperature of 4the cushioning liquid. In other words, when the liquid is at the upper limit of temperature and iows most readily, the opening or size of the passage is least, andas the .temperature of the liquid is lowered and the viscosity increased, the size of the opening is accordingly increased to render the operation of the device luniform and independent of changes in tem- 933,076 and Shultz No. 1,426,115. VThis shock i absorber comprises an annular casing 10 provided with abase portion 12 for attachment to a vehicle frame and externall threaded to receive a cover 14. Mounted within the casing is a head 16 which divides the interiorv A into two separate chambers .18 and 20 r of which is supplied with a cushioning l1qu1d each such as oil or'glycerine. The chamber 18, which is conveniently termed the pressure chamber, is divided transversely by a partition member com rising a central hub 26 mounted on a pro]ecting boss 28 formed inte al with the base 12. The hub is provided with two radial fin vportions 30 locked in slots formed in o posite sides of the casingand forming a llquid-tight partition extending transversely thereof. The chamber 20, which may be termed a replenishing chamber, communicates with the pressure chamber to keep the-latter constantlysupplied with cushion- "2 ing liquid: vReceived within the pressure.

chamber and closely engaging the walls thereof are' pistons or -movable members formed integral with a hub 33 journaled on the endof the'boss 28. Thehub 33 is formed 'as a art-of a hollowshaft 34 journaled in a bushing 35 which is received in a bearing portion 36 of the head 16,'as indicated clearly 1n Fig.` 1. Keyed tothe shaft 34 is an arm 38 connected in the usual ymanner with the motor vehicle and designed to oscillate in accordance with spring flexure. The arm is retained in place on the shaft by a lock nut 40. The abrupt movements `of the spring are checkedor dampened through the dash-pot eiect created by the movements of the istons in the pressure chamber. A -reasona ly free movement in one direction of the pistons is provided for through lthe employment i of ball check\valves 42.- Movement of the pistons in the o posite direction is controlled in accordance with the rate of ow ofthe cushioning liquid :fromv one chamber to another. Upon the return movement of the istons,

the check valves arevclosed and the hquid is Y' compelled to ow throughpassages 50 and 52 formed in the hub 33 communicating with each pair of chambers. Communication between the chambers is aiorded by two sets of radial ports 54and 55 formed in avalve plug 56. The two sets of ports' are in constant communication with the transverse passages and 52 communicating with one another through. a central borel 58. .The rate of flow of the cushioning liquidthrough the passa e is controlled by. a metering lpin threa ed in a head 62 which in turn is threaded within the lock nut 4.0. By properlyadjusting this meterin pin with relation to the r seat 64, shock absor ing action'may be Vprop-` erly adjusted with res ect to load. In'addition to this manual a ustment for di'erent sizes and'weights o f'vehicles, the rate of How of the liquid is automatically maintained constant, irrespective of the viscosity ofthe liqeuid, through a thermostatic element 70,-

o'f the shaft 34 and are prevented from d iswhich, in the present invention, consists of a metallic bellows 72 forming a part of thel metering pin 60 andilled with a fluid 74 which expands and contracts with variations i n temperature. As the temperature increases, the expansion of the fluid elongates the metering in, restricts the passage, and compensates or-the decreased viscosity of the cushioning liqui in warmer weather. On the contrar as the temperature drops, the metallic be lows contract with the consequent contraction in length of the metering pin and an increase in size of the passage to compensate for increased viscosity of. the cushioning liquid. By properly gauging the length of the met-allie bellows' and employing a. suitable iuid therein, the metering pin can be caused to auto-A matically' a ust the Asize ofthe passage to compensate or the changes in the rate of ow .otherwise due tov changes in viscosity of the cushioning liquid. The metallic bellows preferably lit within the axle bore 75.

tortion'through `'engagement with the surrounding wall of 4the bore. Although different luids or gases may be employed within the hermetically 'sealed bellows, it is considered preferable'to employ glycerinegor a substance similar in its characteristics to the 'iiuid employedv within 4the shock absorbers. The opposite ends of the metallic bellows may be hermetically sealed iny any known manner, as through the use 'of solder or suitabl shaped heads which rigidly clam the en s ofthe bellows in a manner to sea them.

A somewhat diier'ent form of vehicle shock absorber ,is illustrated in Fig.v 3. In this form, a vertical casin '8O is attached to thevehicle 'frame throug lu 82 and is rom5 vided withv al transverses aft l84 exten ing through the 'casing-'and connected within thecasing to an arm 86 whichl in turn is connected with a plunger 88 through a short link 90. The plunger and arm are normally maintained in approximately the position s hown through a spring 92. The lunger slides within an open cylinder 94 ormed within the casing, as indicated. VUpon an upward movement ofthe plunger 4throu h a move- 115 ment of the arm 86, liquid is permitted to pass freely from the'outer chamber into the chamber beneath the plunger; through a gravity operated check valve 96.' The return movement of the plunger is checked by the 1i uid from the inner chamber to the outer through a slot'. 98 formed in a sleeve valve 100 as well 'as through a restricted orifice 102controlled 120. -therebeneath which is compelled to ow valve having the opening 98 formed therein is provided with a thermostatic control indicated at and with a manual control through the stem 106 threaded in a nut 108, which in turn is threaded in the casing. The manual adjustment permits regulation of the opening for different loads and the employment of the-metallic bellows ordinarily compensates for variations in the viscosity of the cushioning liquid. The oil within the casing may be'replenished by a ller pipe 110.

What is claimed is v l. A shock absorber for motor vehicles comprising a casing having a chamber adapted to contain a cushioning liquid, a shaft projecting within the casing, an arm connected to the shaft and'adapted to oscillate the latter upon spring flexure, a piston connected with the shaft, a partition having a valve controlledorifice through which the cushioning liquid is forced by working movement of the piston, a bellows thermostat, and metering means connected with the thermostat and movable directly with eX- pansion and contraction thereof for automatically adjusting the size of the orifice in accordance with variations in temperature of the cushioning liquid in the chamber.

2. A shock absorber for motor vehicles comprising a chamber adapted to contain a cushioning liquid, a partition having an oriiice through which liquid is forced from one portion of the chamber to another, means for forcing the liquid through the orifice, a bellows thermostat, and a metering member connected thereto and movable thereby for varying the size of the orifice to vary the resista-nce to flow of the liquid therethrough to compensate for viscosity changes in the liquid caused by changes in temperature.

3. In a shock absorber for motor vehicles, the combination with a liquid container having a by-,pass passageway of -a metering member for controlling one of the ports connecting said by-pass passageway with said container, and a bellows thermostat directly connected to said metering member to 'control the opening of said communicating port by lengthwise movement of the metering member to preserve uniform displacement of liquid under all temperatures.

4. A shock absorber for motor vehicles comprising in combination'4 with an operative connection a lliquid container and a member movably arranged therein and c011- nected to said connection, there being a suitable by-pass passageway provided to permit flow of liquid from one side of said movable member to the other, of a metering pin in said passageway for regulating and controlling the iiow of liquid therethrough, and a bellows thermostat for operating said metering pin in accordance with the prevailing temperature.

5. A shock absorber for motor.` vehicles comprising in combination a liquid container, a mem er movably arranged therein and operatively connected to a spring mechanism 'which it is desired to control, a by-pass connection communicating with said container to by-pass liquid on the opposite sides arranged therein and operatively connectedv actuating member, a by-pass connecto sai tion for by-passing the fluid on opposite sides of said piston when the latter is operated on the working stroke, a metering valve member interposed in said by-pass connection to control the passage of Huid therethrough, a bellows thermostat, and operative connections between said bellows thermostat and said metering valve member for adjusting the latter in accordance with the temperature. j

7 A shock absorber for motor vehicles comprising a casing having a chamber adapted to contain a cushioning liquid, a shaft projecting within the casing, an arm connected to the shaft and adapted to oscillate the latter upon spring leXure, a piston connected -with the shaft, a partition having an orifice through which liquid is forced from one portion of the chamber to another upon the working stroke of the piston, metering means for controlling liquid flow through the orifice, a bellows thermostat directly connected to the metering means to automatically adjust the o riiice in accordance with changes in temperature, and means for'adjustably supporting the bellows thermostat at its outer end.

MELVIN R. J ENNEY.A

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