CA1058229A - Energy absorber with conical control elements - Google Patents
Energy absorber with conical control elementsInfo
- Publication number
- CA1058229A CA1058229A CA259,308A CA259308A CA1058229A CA 1058229 A CA1058229 A CA 1058229A CA 259308 A CA259308 A CA 259308A CA 1058229 A CA1058229 A CA 1058229A
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- Canada
- Prior art keywords
- piston
- chamber
- sleeve member
- housing
- sleeve
- Prior art date
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Abstract
SHOCK ABSORBER WITH CONICAL
CONTROL ELEMENTS
ABSTRACT OF THE DISCLOSURE
An adjustable energy absorber including a housing having a ram slidably extending therefrom. A first control sleeve divides the housing into a pair of fluid chambers, which sleeve has an axially extending row of openings to provide communi-cation between the two chambers. A second control sleeve sur-rounds the first sleeve and is nonrotatably connected thereto.
The first and second sleeves have compatible outer and inner conical surfaces, respectively. The first and second sleeves are axially adjustable with respect to one another to form a narrow flow passage between the opposed conical surfaces. Imposition of a force on the ram causes fluid to be forced from one chamber through the openings into the flow passage, and then into the other chamber. By varying the width of the flow passage, as by axially moving one control sleeve relative to the other, the amount of energy absorbed by the fluid during the movement of the ram can be selectably adjusted.
CONTROL ELEMENTS
ABSTRACT OF THE DISCLOSURE
An adjustable energy absorber including a housing having a ram slidably extending therefrom. A first control sleeve divides the housing into a pair of fluid chambers, which sleeve has an axially extending row of openings to provide communi-cation between the two chambers. A second control sleeve sur-rounds the first sleeve and is nonrotatably connected thereto.
The first and second sleeves have compatible outer and inner conical surfaces, respectively. The first and second sleeves are axially adjustable with respect to one another to form a narrow flow passage between the opposed conical surfaces. Imposition of a force on the ram causes fluid to be forced from one chamber through the openings into the flow passage, and then into the other chamber. By varying the width of the flow passage, as by axially moving one control sleeve relative to the other, the amount of energy absorbed by the fluid during the movement of the ram can be selectably adjusted.
Description
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FIELD OF THE INVENTION
This invention relates generally to energy absorbers and, in particular, to an adjustable hydraulic shock absorber which is capable of being adjusted to absorb shock loads of varying amounts.
BACKGROUND OF THE INVENTION
Energy absorbers have often been customized or built in accordance with the requirements of the particular load condi-tions under which they were to perform. This is highly undesir-able since building a shock absorber for each type of job iscostly and time consuming. Further, customized shock absorbers are necessarily of many different sizes and there is generally no standardization among the indiviudal components thereof, thereby making maintenance expensive and difficult.
To overcome the above disadvantage, several energy absorbers have been commercially manufactured which permit the energy absorbing capability thereof to be adjusted in accordance with the expected load conditions, thereby permitting the shock absorber to be utilized in many different loading and environ-mental conditions. While many of these adjustable energyabsorbers have been adaptable to a wide range of load conditions, nevertheless these energy absorbers have not been as widely utilized as the area of need for same might indicate since they have been relatively costly. Specifically, most known adjustable energy absorbers have utilized a complex adjustment structure which is both expensive to manufacture and difficult to use.
More specifically, these known shock absorbers have required an excessive amount of precise, and hence costly machining.
FIELD OF THE INVENTION
This invention relates generally to energy absorbers and, in particular, to an adjustable hydraulic shock absorber which is capable of being adjusted to absorb shock loads of varying amounts.
BACKGROUND OF THE INVENTION
Energy absorbers have often been customized or built in accordance with the requirements of the particular load condi-tions under which they were to perform. This is highly undesir-able since building a shock absorber for each type of job iscostly and time consuming. Further, customized shock absorbers are necessarily of many different sizes and there is generally no standardization among the indiviudal components thereof, thereby making maintenance expensive and difficult.
To overcome the above disadvantage, several energy absorbers have been commercially manufactured which permit the energy absorbing capability thereof to be adjusted in accordance with the expected load conditions, thereby permitting the shock absorber to be utilized in many different loading and environ-mental conditions. While many of these adjustable energyabsorbers have been adaptable to a wide range of load conditions, nevertheless these energy absorbers have not been as widely utilized as the area of need for same might indicate since they have been relatively costly. Specifically, most known adjustable energy absorbers have utilized a complex adjustment structure which is both expensive to manufacture and difficult to use.
More specifically, these known shock absorbers have required an excessive amount of precise, and hence costly machining.
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Also, many of the known adjustable shock absorbers use concentric, inner and outer control sleeves which are relatively movable for controlling flow between two chambers. However, these sleeves must be machined with extremely precise tolerances and/or machined as a matched pair in order to permit proper fit and operation. This thus prevents random assembly of the parts, and hence substantially increases the cost of assembly.
Accordingly, it is an object of this invention to provide an improved energy absorber, particularly a hydraulic shock absorber, which overcomes the above-mentioned disadvantages.
It is also an object of this invention to provide:
1. An improved energy absorber, as aforesaid, capable of being adjusted to absorb shock loads of varying amounts.
2. An energy absorber, as aforesaid, which is easily and precisely ad~ustable to vary the energy absorption characteristic thereof.
Also, many of the known adjustable shock absorbers use concentric, inner and outer control sleeves which are relatively movable for controlling flow between two chambers. However, these sleeves must be machined with extremely precise tolerances and/or machined as a matched pair in order to permit proper fit and operation. This thus prevents random assembly of the parts, and hence substantially increases the cost of assembly.
Accordingly, it is an object of this invention to provide an improved energy absorber, particularly a hydraulic shock absorber, which overcomes the above-mentioned disadvantages.
It is also an object of this invention to provide:
1. An improved energy absorber, as aforesaid, capable of being adjusted to absorb shock loads of varying amounts.
2. An energy absorber, as aforesaid, which is easily and precisely ad~ustable to vary the energy absorption characteristic thereof.
3. An energy absorber, as aforesaid, which permits the energy absorption characteristic to be precisely adjusted to a level compatible with the external load imposed thereon.
4. An energy absorber, as aforesiad, which is capable of absorbing progressively increasing amounts of energy so as to result in a substantially uniform, that is a substantially linear, stopping of a movable load.
5. An energy absorber, as aforesaid, which utilizes a control structure containing inner and outer concentric sleeves with one sleeve having an axially extending row of control openings therethrough, which sleeves have opposed conical sur-faces thereon and are relatively axially movable to form a variable width flow control passage therebetween and thereby ~05~ 9 control the flow of fluid between two compartments so as to adjust the energy absorption capability of the shock absorber.
6. An energy absorber, as aforesaid, which permits the inner and outer control sleeves to be machined with normal tolerances while still permitting random selection of parts during assembly.
7. An energy absorber, as aforesaid, which is simple and compact in construction, economical to manufacture, efficient in operation, and simple to adjust.
Other objects and purposes of this lnvention will be ap-parent to persons acquainted with apparatuses of this type upon reading the following specification and inspecting the accompany-ing drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a central sectional view of an adjustable energy absorber according to the present invention.
Figure 2 is a fragmentary sectional view taken along the line II-II in Figure 1.
Figure 3 is a fragmentary sectional view of thepiston assembly and showing the position thereof when the ram is being pushed into the shock absorber.
Figure 4 is a view similar to Figure 3 but showing the piston assembly when the ram is being moved outwardly of the shock absorber, in which position the piston functio~s as an opened one-way check valve.
Figure 5 is a central sectional view of a further embodiment according to the present invention.
Figure 6 is an enlarged, fragmentary sectional view taken along the line VI-VI in Figure 5.
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Figure 7 is a view similar to Figure 6 but illustrating the inner and outer control sleeves in an open or spaced con-dition.
Figure 8 is a fragmentary sectional view taken substan-tially along the line VIII-VIII in Figure 7.
Figure 9 is a central sectional view showing a preferred embodiment of an adjustable energy absorber.
Figure 10 is a fragmentary sectional view along line X-X in Figure 9.
Figure 11 is a view similar to Figure 10 but showing the control sleeves in a spaced or open condition.
Figure 12 is a fragmentary sectional view taken along line XII-XII in Figure 11.
Figure 13 is an enlarged, fragmentary, central sectional view of the piston end of the ram.
Figure 14 is an enlarged, fragmentary sectional view of a modified structure.
SUMMARY OF THE INVENTION
The objects and purposes of the present invention are met by providing an energy absorber having a housing which contains an adjustable sleeve means therein, which sleeve means divides the housing into a pair of fluid chambers. A
ram extends from the housing and has a piston slidably received within one of the fluid chambers. The adjustable sleeve means includes inner and outer concentric control sleeves which can be selectively axially displaced one relative to the other. One of the sleeves has an axially extending row of control openings extending therethrough. The con-centric control sleeves have opposed conical surfaces which ~5~3~2~
can be disposed in substantial engagement with one another to thereby close off the control openings and prevent flow of fluid between the fluid chambers. By relatively axially moving the concentric control sleeves away from this position, so that the opposed conical surfaces are slightly spaced from one another, there is formed a flow control passage between the concentric control sleeves which, in conjunction with the control openings, permits the controlled flow of fluid between the chambers. Im-position of an external force on the ram caused the piston to move axially through the one chamber to force fluid therefrom through the control openings and the control passage into the other chamber, while permitting the fluid to absorb some of the ram energy due to the restricted fluid flow through the control openings and the control passage. The piston progressively closes off the control openings as it moves axially into said one chamber to thereby also control the energy absorption characteristic of the shock absorber. The quantity of energy absorbed by the shock absorber can be selectively adjusted by causing relative axial displacement between the control sleeves 0 to thereby vary the size of the control passage.
DETAILED DESCRIPTION
R~ferring to Figures 1-4, there is illustrated an energy absorber 10, specifically a hydraulic shock absorber, which in cludes a housing 11 having a ram assembly 12 slidably positioned in and extending therefrom. A flow control sleeve assembly 13 is positioned within the housing for controlling relative move-ment between the housing 11 and the ram assembly 12 due to the imposition of an external load on the shock absorber. The flow control sleeve rneans 13 is adjustable, as explained hereinafter, to permit the quantity of energy absorbed by the shock absorber to be selectively varied.
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The housing 11 includes a hollow cylindrical sleeve 16 fixedly connected between a pair of end members 17 and 18.
The flow control sleeve means 13 includes an inner cylin-drical control sleeve 21 positioned within the housing and ex-tending substantially the full axial length thereof. The sleeve 21 is rotatably received at one end within a bore 22 formed within and extending through the end member 17. The other end of sleeve 21 has a stub shaft 23 fixedly connected thereto, which stub shaft 23 closes off the end of a chamber 27 defined within the control sleeve 21 and projects through an opening 24 formed in the end member 18, whereby stub shaft 23 is rotatably supported on the end member. A retainer ring 26 coacts between stub shaft 23 and end member 18, whereby the stub shaft 23 maintains the sleeve 21 axially fixed with respect to the housing 11.
The ram assembly 12 includes a cup-shap~d piston 28 which is snugly and slidably received within the chamber 27, which piston 28 is connected to an elongated piston rod 29 by a threaded bolt 31. The piston rod 29 is slidably and sealingly support~d by a bushing 39 which is fixedly positioned within the end of sleeve 21.
The bolt 31 and the cup-shaped piston 28 have suitable clearance passages therein for defining a one-way check valve structure to assist in channelling fluid into the chamber 27 when the ram assembly is being extended, that is, being moved leftwardly in Figure 1.
Referring to Figures 3 and 4, the bolt 31 has an inter-mediate cylindrical shank portion 32 which extends through a hole 33 formed in the end wall of the piston 28, which hole is of larger diameter than the shank portion so as to define an annular clearance passage 34 therebetween. The shank portion 32 has a length which is greater than the thickness of the bottom wall of the piston 28 so that the piston 28 can move axially relative to the piston rod 29 between the two positions illustrated in Figures 3 and 4. When the piston 28 is in its outermost position as illustrated in Figure 4, there is thus defined a small clearance space or chamber 36 between the piston and the adjacent end of the piston rod 29, which space 36 com-municates with a pair of grooves 37 which are formed in the piston and extend axially through the free end thereof. The grooves 37 at their rearward (leftward) ends communicate with a chamber 38 which is formed between the piston 28 and the bushing 39 when the ram assembly is displaced inwardly (right-wardly in Figure 1) from its fully extended position. ~he piston 28 also has grooves 35 on the front face thereof which provide communication between the passage 34 and the chamber 27.
As illustrated in Figure 3, when the ram assembly is being contracted (moved rightwardly in Figure 1), the piston 28 is moved into abutting engagement with the free end of the piston rod 29. The intermediate chamber 36 between the piston and the piston rod i5 thus closed off so that passage 34 is isolated from the grooves 37.
The ram assembly 12 has the piston rod 29 thereof projecting outwardly from the housing, which piston rod is provided with an enlarged head 41 fixedly mounted thereon. A compression spring 42 surrounds the piston rod 29 and coacts between the head 41 and a retainer ring 43 for resiliently urging the ram assembly 12 into its outermost or fully extended positlon as illustrated in Figure 1. In this full~ extended position, the piston 28 abuts against the bushing 39, and the piston 28 abuts against the head of the ~5~
bolt 31. While the spring 42 has been illustrated as disposed externally of the housingr it will be appreciated that the spring could be positioned within thehousing if desired.
The flow control sleeve assembly 13 also includes an outer cylindrical control sleeve 46 disposed concentric with and in surrounding relationship to the inner control sleeve 21. The outer sleeve 46 has one end thersof joined to the housing 11, specifically the end member 18, by means of a threaded con-nection 47 which normally maintains the outer control sleeve 46 stationary relative to the housing during normal operation of the shock absorber. However, threaded connection 47 permits the outer sleeve 46 to be rotated relative to the housing when adjustment of the controlsleeve assembly 13 is desired.
The outer control sleeve 46 is, in the illustrated embodi-ment, nonrotatably connected to the inner control sleeve 21 by a pair of pins 48 which as fixed to sleeve 46 and project in-wardly thereform. The pins 48 extend into axially elongated slots 49 formed on diametrically opposite sides of the inner sleeve 21.
This pin-and-slot connection between sleeves 21 and 46 prevents relative rotation therebetween but permits the outer sleeve 46 to be axially displaced relative to the inner sleeve 21 when the complete sleeve assembly 13 is rotated relative to the housing 11.
The control sleeves have opposed conical surfaces formed thereon for controlling the energy absorption characteristic of the shock absorber, and for this purpose the outer control sleeve 46 has an inner conical surface 52 thereon which is disposed op-posite and is adapted to be engaged with an outer conical sur-face 51 as formed on the inner control sleeve 21. The inner and outer conical surfaces 51 and 52, respectively, are of an identi-cal taper, which taper preferably extends at a small angle.
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relative to the longitudinally extending axis A of the shockabsorber. In the illustrated embodiment, the taper of the conical surfaces is normally within the range of between 1 and 5, although the present lnvention also contemplates the use of a larger angle oE taper. The conical surfaces 51 and 52 are maintained in engagement with one another when the sleeve as-sembly 13 is in its fully closed position, in which position the outer sleeve 46 is in its leftwardmost position whereupon the rightward end of sleeve 46 is thus spaced from the end wall of end member 18. However, Figure 1 illustrates the sleeve 46 in its rightwardmost position whereupon the sleeve assembly 13 is in its fully opened condition so that a maximum annular flow pass~ge 53 is formed between the conical surfaces 51 and 52.
This annular flow control passage 53, as formed between the coni-cal surfaces of the control sleeves, communicates with the chamber 27 through an axially extending row of openings 54 as formed in the sidewall of the inner control sleeve 21. The large diameter end of the flow passage 53, that is the leftward end in Figure 1, communicates with a chamber 56 which is formed within the housing 11 in surrounding relationship tothe sleeve assembly 13.
The chamber 56 is in continuous communication with the chamber 38, and for this purpose the end member 17 is provided with a pair of passages or grooves 58 formed therein, which grooves have their rearward ends in communication with openings 59 formed in sleeve 21, which openings communicate with chamber 38.
OPERATIO~
In an operational position, the energy absorber 10 is normally maintained with its ram assembly 12 in an extended position as illustrated in Figure 1 due to the urging of spring ~51~
42. The absorber 10 is filled with fluid, such as hydraulic oil, so that the fluid completely fills at least the chamber 27.
When so prepared, the energy absorber 10 is in condition for engagement by an apparatus from which energy is to be absorbed, which apparatus will move the piston rod inwardly into the housing for decelerating the apparatus or absorbing shock blows therefrom.
When an external load or shock blow is imposed on the ram assembly 12, this causes the piston rod 29 to move inwardly into the housing, which in turn causes inward (rightward) movement of the piston 28. During this rightward movement of the piston, the piston is maintained in the position illustrated in Figure 3 so that the one-way check valve structure formed therein is closed. The inward movement of piston 28 causes pressurization of the fluid contained within the inner chamber 27, which fluid is forced through the openings 54 and through flow passage 53 into the outer chamber 56. As the piston 28 moves axially toward therightward end of the housing, it sequentially closes off the openings 54, which in turn progressively restricts the further flow of fluid from the chamber 27 into the chamber 56. This thus causes the piston 28 to progressively decelerate so that as the piston approaches the inner end of the chamber 27 (rightward end in Figure 1), the external shock load imposed on the shock absorber 10 will be substantially dissipated.
During the inward movement of the ram assembly, as explained above, the chamber 38 as formed behin~ the piston 28 progressively enlarges. This chamber 38 fills with fluid due to its communi-cation with chamber 56 through the passages S8 and openings 59.
When the inward movement of the ram assembly has been stopped and when the external load has been removed from the head portion 41, the ram assembly is returned to its original la)~ 3 extended position due to the urging of the spring 42. During this return movement of the ram assembly, the fluid in chamber 38 causes the piston 28 to be moved rightwardly relative to the piston rod 29 so as to assume the position illustrated in Figure 4, in which position the intermediate chamber 36 is opened so as to permit communication between the passages 34 and 37. This one-way check valve structure as formed by the passages 34-37 thus facilitates the flow of fluid from chamber 38 into chamber 27 as the ram assembly is being returned to its fully extended position. When the ram is fully extended~ the openings 62 ensure that the chamber 21 is completely filled with fluid.
As is understood, the deceleration rate of the ram assembly 12 is determined by the quantity and velocity of the fluid escaping from the inner chamber 27 through the openings 54 and passage 53 into the outer chamber 56. To adjust the deceleration rate of the ram assembly 12, and thereby vary the energy dis-sipating characteristic of the shock absorber 10, the complete sleeve assembly 13 is rotated relativa to the housing 11, which rotation can be accomplished by manually turning the hand wheel 61, which hand wheel could also be mounted on the stub shaft 23 if desired. This rotation of the sleeve assembly 13 causes the outer control sleeve 46 to be axially displaced relative to the inner sleeve 21 due to the threaded connection 47. Since the sleeve assembly can be rotated through an arcuate distance equal to severai complete revolutions, this thus permits a very fineand precise adjustment in terms of the axial displacement of the outer sleeve 46 relative to the inner sleeve 21, which axial adjustme~t in turn varies the radial spacing between the conical surfaces 51 and 52 and hence varies the cross-sectional area of the annular flow passage 53.
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MODIFICATION
Figures 5-8 illustrate therein a preferred embodiment of the invention which incorporates therein many of the structural and operational features possessed by the shock absorber 10 of Figures 1-4. Accordingly, the parts of the shock absorber il-lustrated in Figures 5~8 have been designated by the same reference numerals used to designate corresponding parts of the shock absorber illustrated in Figures 1-4 except that the reference numerals have been increased by 100.
In the shock absorber 110, the inner control sleeve 121 extends between and is supported on the end members 117 and 118, and the outer control sleeve 146 is disposed concentric with and in surrounding relationship to the inner sleeve 121. Outer sleeve 146 has an inner conical surface 152 thereon which is disposed opposite the outer conical surface 151 formed on the inner sleeve 121, which conical surfaces are adapted to be slightly spaced apart so as to provide a flow control passage 153 therebetween.
In this embodiment, the inner control sleeve 121 is pro-vided with a pair of elongated slots 171 (Figures 6 and 7) formed in the outer conical surface 151, which slots 171 extend axially of the sleeve 121 throughout the length of the outer sleeve 146 and terminate in openings 171A (Figure 8) which communicate with the outer chamber 156. The slots 171 are disposed closely adjacent and on opposite sides of the axially extending row of openings 154, whereby the slots result in the formation of narrow circumferentially extending lands 172 between the row of openings 154 and the adjacent slots 171. These lands 172 are spaced from the opposed inner conical surfac~ 152 and thus define narrow con-trol passages 173 therebetween for controlling the fluid flow ~)58Z2~
from the openings 154 into the slots 171.
The slots 171 are formed in the sleeve 121, as by a milling cutter, such that the bottom wall of each slot extends substan-tially parallel to the axis A. This results in the cross-sectional area of each slot 171 progressively increasing as the slot extends from the inner or rightward end thereof to the outer or leftward end thereof as illustrated in Figure 8. The slot 171 is thus effectively of zero cross-sectional area at the rightward end of the control sleeve 146, whereas the slot 171 progressively increases in cross-sectional area so as to have a maximum cross-sectional area adjacent the leftward end of the control sleeve 146.
While Figures 6 and 7 illustrate the use of two slots 171, with one being positioned on each side of the row of openings 154, it will be appreciated that the shock absorber 110 could be provided with only a single slot 171 if desired.
The outer control sleeve 146 is axially adjustable relative to the inner control sleeve 121 so as to vary the radlal width or dimension or the passages 153 and 173. For this purpose, shock absorber 110 is provided with an adjustment means 114 which includes a knob or handle 176 fixedly secured to the outer end of a control shaft 177, which control shaft is in turn rotatably and sealingly supported on a housing hub 178 so that the control shaft 177 is rotatable about an axis which extends substantially perpendicular to the axis A. Control shaft 177 has a cam or eccentric 179 fixedly secured to the inner end thereof, which eccentric 179 is engaged with an opening or slot 181 formed in the outer control sleeve 146. The eccentric 179 is preferably of circular cross-section and has the axis thereof eccentrically displaced from the axis of the shaft 177, whereby eccentric 179 functions like a crankpin. The slot 181 has a ~5~
width, as measured in the axial direction of the control sleeve, which substantially corresponds to the diameter of the eccen-tric 179 so that the eccentric is snugly accommodated therein.
However, the length of the slot 181, as measured circumferenti-ally of the control sleeve, is preferably greater than the diameter of the eccentric to thereby compensate for the sideward displacement of the eccentric during rotation of the control shaft 177.
The control shaft 177 is rotatable through a maximum angle of 180, and preferably less, so as to cause a corresponding rotation of the eccentric 179, which in turn causes axial dis-placement of control sleeve 146 between two endmost positions~
When the adjustment mechanism is in the position illustrated in Figure 5, in which position the eccentric is in its leftward end position, the outer control sleeve 146 effectively abuts against a stop 182 as formed on the inner control sleeve 121, thereby resulting in a minimum clearance between the conical surfaces 151 and 152 so that the openings 154 are effectively closed. The presence of the stop 182, however, prevents the two conical surfaces 151 and 152 from being lockingly wedged to-gether. When the controlknob 176 and eccentric 179 are rotated away from the position illustrated in Figure 5, then the outer control sleeve 146 is moved axially rightwardly so that the spacing 153 between the conical surfaces 151 and 152 is in-creased, with the maximum spacing 153 existing when the end of sleeve 146 abuts against the stop surface 188. Rotation of knob 176 thus permits the spacing 153 between the conical sur-faces 151 and 152 to be selectively varied and adjusted so as to provide for the desired restricted flow of fluid from the inner chamber 127 into the outer chamber 156 when the ram assembly 112 ~,~5~fæ~
is moved inwardly into the housing 111.
The shock absorber can be suitably locked in its selected position by means of a set screw 183 which locks the knob 176 to the hub 178 and thereby fixedly maintains the positional relationship between the control sleeves 121 and 146.
The housing has a port 186 associated therewith for per-mitting filling of the shock absorber with fluid, such as hydraulic oil. After filling, the port 186 is normally closed by means of a conventional plug.
When an external load or shock force is imposed on the ram assembly 112, the piston 128 moves inwardly (rightwardly) into the compartment 127, thereby forcing fluid outwardly through the openings 154. The fluid then flows over the land 172 into the slots 171, since this is the path of least flow resistance. The fluid then flows along the slots 171 and discharges through the ends 171A thereof into the outer chamber 156. The restriction imposed on the fluid flow by the openings 154 and control pas-sages 173 thus absorbs the energy of the apparatus which is impacting against the ram assembly, and accordingly caused a deceleration of the ram assembly.
As the ram assembly moves further into the compartment 127, the piston 128 progressively closes off the openings 154 so that the flow of fluid from chamber 127 into chamber 156 is further progressively restricted, thereby causing a progressive deceleration of the ram assembly as it approaches the rightward end of the shock absorber. This progressive closing of the openings 154, coupled with the flow passage 173 formed between the openings 154 and the slots 171, thus causes a very uniform deceleration and stopping of the ram assembly. Further, since the grooves 171 are of progressively increasing cross-sectional ~5~Z~
area, they readily accommodate the variable flow therethrough depending upon the number of openings 154 which are uncovered.
For example, when the pi.ston 128 is adjacent the leftward end of the shock absorber, a large number of openings 154 are un-covered so that fluid will flow through the openings 154 into the slots 171 along substantially the complete length thereof, whereupon a large quantity of fluid will flow into the slots for passage into the outer chamber 156. This larger quantity of fluid is permitted since the cross-sectional area of the slots 171 progressively increases towards the discharge end of theslots in correspondence with the progressive spac-ing of the openings axially along the inner control sleeve.
On the other hand, when the piston 128 is more closely adja-cent the rightward end of the shock absorber, only a few open-ings 154 are uncovered so that a substantially smaller quan-tity of fluid flows into the slots 171 for discharge into the outer chamber 176.
It will be appreciated that the adjustment mechanism 114 could be replaced with other suitable mechanisms capable of causing the desired axial movement between the sleeves 121 and 146.
Figure 9 illustrates an energy absorber 210, specifically a hydraulic shoc~ absorber, which includes a housing 211 having a ram assembly 212 slidably positioned in and extend-ingtherefrom. A flow control sleeve assembly 213 is posi-tioned within the housing for controlling relative movement between the ram assembly 212 and the housing 211 due to imposition of an external load on the shock absorber. The flow control sleeve assembly 213 is adjustable, as explained hereinafter, to permit the quantity of energy absorbed to be selectively varied.
The housing 211 includes a hollow cylindrical sleeve 216 fixedly connected between a pair of end members 217 and 218~
The flow control sleeve assembly 213 includes an inner cylindrical control sleeve 219 positioned within the housing and extending substantially the full axial length thereof.
The sleeve 219 is fixed with respect to the housing and has the rightward end thereof pressed onto a member 221 which abuts against the end member 217~ The leftward end of sleeve 219 is snugly seated on an annular projection 222 which extends inwardly from a bearing sleeve 222 which is fixedly and sealingly mounted on the other end member 218.
A conical wall 223 is formed on the inner edge of the left-ward end of sleeve 219, and a conventional elastomeric O-ring 224 is clampingly engaged between the wall 223 and the corner defined on the end member 218 to create a sealed re-lationship therebetween. Thisstructure overcomes any pro-blem caused during the assembly of the shock absorber dueto the accumulation of axial tolerances on the individual parts, whereby the individual parts can be manufactured with less stringent tolerances and a-t the same time permit a more efficient assembly of the shock absorber.
As an alternative, the leftward end of sleeve 219 can have an annular recess 223' formed therein, as shown in Figure 14, so as to accommodate the O-ring 224'.
The ram assembly 212 has a substantially cylindrical piston 226 on the inner end thereof, which piston is dis-posed within a chamber 227 defined within the inner control sleeve 219 and is slidably guided for axial movement there-along. The piston 226 is fixedly secured on the inner end of a piston rod 228. The piston rod has a reduced dia-meter portion for accommodating the piston thereon, which piston abuts against a shoulder 229 formed on the rod 228.
The piston 226 and piston rod 228 have aligned holes 231A
and 231B (Figure 13) extending diametrically thereacross, which holes receive therein an elongated axially split spring pin 232. The pin 232 expands circumferentially to be snugly accommodated within the holes 231A-231B so as to fixedly interconnect the piston and the piston rod.
The piston 226 has an annular groove 233 extending therearound, which groove communicates with the holes 231.
A conventional annular split piston ring 234 may, if neces~
sary, be disposed in the groove 233 to create a slidable sealed engagement with the inner wall of the sleeve 21g.
Piston ring 234 also retains the spring pin 232 within the holes 231.
A one-way check valve assembly 236 is associated with the inner end of the ram assembly, particularly the piston 226. This check valve assembly 236, as shown in Figures 9 and 13, includes a first passage formed as a large diametex bore 237 extending coaxially inwardly from the inner free end of the piston rod 228. This bore 237 in turn communicates with and is coaxially aligned with a further passage formed as a small diameter bore 238. A further passage 239 extends radially of the piston rod adjacent the rear face of the piston and communicates with the bore 238 adjacent the axially inner end thereof. The radially outer end of transverse passage 239 communicates with a chamber 2~1 ~5~
which is formed within the sleeve 219 and is located between the opposed axial faces of the piston 226 and the end hub 222A when the piston 226 is moved slightly inwardly away from the end hub as shown in Figure 9.
To control flow through the passage arrangement defined by the passages 237, 238 and 239, there is provided a movable valve member in the form of a ball 243 which is adapted to seat against an annular conical valve seat 242 formed at the junction between the bores 237 and 238. The ball 2g3 is disposed in the large bore 237 and is of a larger diameter than the bore 238. The ball 243 is confined in the bore 237 by the locking pin 232 which extends diametrically across the bore 237 but is spaced axially a small distance from the ball 243 to permit movement of the ball away from the seat 242 so as to permit flow through the passage arrangement.
The inner control sleeve 219 has small holes247 formed through the wall thereof and communicating at the radially outer ends with an outer annular chamber 246 formed between the sleeve assembly 213 and the outer housing sleeve 216.
The holes 247 are disposed adjacent the leftward end of the sleeve 219, which end has the piston 226 associated there-with when the shock absorber is in its extended position.
The holes 247 are positioned directly adjacent the inner axial face of the hub 222A so that the holes thus communicate with the chamber 241 at all times. One of the holes 247 has the radially inner end thereof joined in flow communica-tion with an axially extending groove 248 formed in the inner wall of the sleeve 219, which groove 248 terminates at a location which is disposed slightly forwardly of the front face of the piston 226 when the ram assembly is in its ~s~
fully extended position.
The flow control sleeve assembly 213 also includes an outer cylindrical control sleeve 251 disposed concentric with and in surrounding relationship to the inner conrol sleeve 219.
The outer sleeve 251 has the rightward end thereof axially spaced from the end member 217, whereby outer sleeve 251 can thus be moved axially through a limited extent relative to the inner sleeve 219.
The control sleeves 219 and 251 have opposed conical surfaces formed thereon for permitting adjustment in the energy absorption characteristic of the shock absorber~
For this purpose, the outer control sleeve 251 has an inner conical surface 253 which is disposed opposite and is adapted to be engaged with an outer conical surface 2~4 as formed on the inner control sleeve 219. The conical surfaces 253 and 254 are of an identical taper, which taper preferably extends at a small angle relative to the longitudinally ex-tending axis A of the shock absorber. In the illustrated embodiment, the taper of the conical surfaces is normally in the range of between 1 and 5, and preferably 2, al-through the present invention also contemplates the use of a larger angle of taper. The conical surfaces 253 and 254 are maintained substantially in engagement with one another when the sleeve assembly 213 is in its fully closed posi-tion, in which position the outer sleeve 251 is in its left-ward most position.
To provide for controlled flow of fluid from the inner chamber 227 through the sleeve assembly 213 to the outer chamber 246, which controlled flow permits the absorption of energy when a shock load is imposed on the absorber, z~
the inner and outer control sleeves are relatively moved into a position in which the opposed conical surfaces 253 and 254 are spaced a small distance apart so as to result in the formation of a small annular space 256 therebetween.
The inner control sleeve 219 is provided with a pair of elongated slots 257 (Figures 10-12) formed in the outer conical surface 254 thereof~ which slots 257 extend axially of the sleeve 219 throuyhout substantially the complete length of the outer sleeve 251. The slots 257 terminate, at the leftward ends thereof, in openings 258 (Figure 12) which communicate with the outer chamber 2~6. The slots 257 are disposed closely adjacent and on opposite sides of an axially extending row of openings 261 which are formed in the inner sleeve 219 and communicate with the inner chamber 227. The slots 257 and their relationship to the row of openings 261 results in the formation of narrow circum-ferentially extending lands 262 between the row of openings 261 and the adjacent slots 257. The lands 262 are adapted to be spaced from the opposed inner conical surface 253 and thus define narrow flow control passages 263 therebetween for controlling the fluid flow from the openings 261 into the slots 257.
The outer control sleeve 251 is axially adjustable re-lative to the inner control sleeve 219 so as to vary the radial width or dimension of the passages 256 and 263. For this purpose, there is provided an adjustment structure 266 which includes a knob or handle 267 fixedly secured to the outer end of a control shaft 268, which control shaft is in turn rotatably and sealingly suppor-ted on a housing hub 269 so that the control shaft is rotatable about an axis ~(~SB~Z91 which extends substantially perpendicular to the axis A.
Control shaft 268 is axially restrained with respect to the housing hub 269 by means of a locking pin 271. Control shaft 268 has a cam or eccentric 272 fixedly secured to the inner end thereof, which eccentric is disposed within an opening or slot 273 formed in the outer control sleeve 251. The eccentric 272 is preferably of circular cross-section and has the axis thereof eccentrically displaced from the axis of the shaft 268, whereby eccentric 272 func-tions like a crankpin. The slot 273 has a width, as mea-sured in the axial direction of the control sleeve 251, which substantially corresponds to the diameter of the eccentric 272 so that same is snugly accommodated in the slot.
However, slot 273 has a length, as measured circumferentially of the control sleeve, which is preferably greater than the diameter of the eccentric to thereby compensate for the side-ward displacement of the eccentric during rotation of the control shaft 268.
The control shaft 268 is rotatable through an angle of approximately 180, and preferably slightly less, so as to cause a corresponding rotation of the eccentric 272, which in turn causes axial displacement of outer control sleeve 251 between two endmost positions. When the adjust-ment structure is in the position illustrated in Figure 9, in which position the eccentric 272 is in its leftward end position, the outer control sleeve 251 effectively abuts against a stop 274 (Figure 12) as formed on the inner control sleeve 219, thereby resulting in a minimum clearance between the conical surfaces 253 and 254 so that the open-ings 261 are effectively closed. The presence of the stop ~5~2'~1 274, however, prevents the two conical surfaces 253 and 254 from being lockingly wedged together.
When the control knob 267 and eccentric 272 are rotated away from the position illustrated in Figure 9, then the outer control sleeve 251 is moved axially rightwardly so that the spacing 256 between the conical surfaces 253 and 254 is increased, with the maximum spacing existing when the sleeve 251 is in its rightward most position.
Rotation of knob 267 thus permits the spacing between the conical surfaces to be selectively varied and adjusted to provide for the desired restricted flow of fluid from the inner chamber 227 into the outer chamber 246 when the ram assembly 212 is moved inwardly into the housing 211.
The shock absorber can be suitably locked in its select-ed position by means of a set screw 276 which locks the knob 267 to the housing hub 269 and thereby fixedly maintains the positional relationship between the control sleeves 219 and 251. Set screw 276 is positioned substantially parallel to the axis of the control shaft 268 and thus projects per-pendicularly from the side of the housing so as to be readily accessible for adjustment, as by means of an Allen wrench or other tool.
The ram assembly 212 has an enlarged head 278 on the outer free end of the piston rod 228, which head 278 is adapted to have the shock loads imposed thereon, and a conventional compression spring 279 surrounds the piston rod 228 and is confined between the head 278 and the bushing 222 to thereby continuously urge the ram assembly into its outward extended position.
Housing 211 has a port 281 associated therewith to permit the shock absorber to be filled with fluid, such as hydraulic oil. This port is normally closed by means of a conventional plug. Chamber 246 also preferably has a compressible spongelike member 282 positioned therein so as to compensate for volume changes caused by the inward movement of the piston rod, which member 282 substantially encircles the sleeve 251 throughout the axial extent thereof. The member 282 is preferably of a rubber or plastic closed-cell structure.
The operation of the embodiment shown in ~igures 9-13 is believed readily apparent from the above structural and operational descriptions.
Other objects and purposes of this lnvention will be ap-parent to persons acquainted with apparatuses of this type upon reading the following specification and inspecting the accompany-ing drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a central sectional view of an adjustable energy absorber according to the present invention.
Figure 2 is a fragmentary sectional view taken along the line II-II in Figure 1.
Figure 3 is a fragmentary sectional view of thepiston assembly and showing the position thereof when the ram is being pushed into the shock absorber.
Figure 4 is a view similar to Figure 3 but showing the piston assembly when the ram is being moved outwardly of the shock absorber, in which position the piston functio~s as an opened one-way check valve.
Figure 5 is a central sectional view of a further embodiment according to the present invention.
Figure 6 is an enlarged, fragmentary sectional view taken along the line VI-VI in Figure 5.
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Figure 7 is a view similar to Figure 6 but illustrating the inner and outer control sleeves in an open or spaced con-dition.
Figure 8 is a fragmentary sectional view taken substan-tially along the line VIII-VIII in Figure 7.
Figure 9 is a central sectional view showing a preferred embodiment of an adjustable energy absorber.
Figure 10 is a fragmentary sectional view along line X-X in Figure 9.
Figure 11 is a view similar to Figure 10 but showing the control sleeves in a spaced or open condition.
Figure 12 is a fragmentary sectional view taken along line XII-XII in Figure 11.
Figure 13 is an enlarged, fragmentary, central sectional view of the piston end of the ram.
Figure 14 is an enlarged, fragmentary sectional view of a modified structure.
SUMMARY OF THE INVENTION
The objects and purposes of the present invention are met by providing an energy absorber having a housing which contains an adjustable sleeve means therein, which sleeve means divides the housing into a pair of fluid chambers. A
ram extends from the housing and has a piston slidably received within one of the fluid chambers. The adjustable sleeve means includes inner and outer concentric control sleeves which can be selectively axially displaced one relative to the other. One of the sleeves has an axially extending row of control openings extending therethrough. The con-centric control sleeves have opposed conical surfaces which ~5~3~2~
can be disposed in substantial engagement with one another to thereby close off the control openings and prevent flow of fluid between the fluid chambers. By relatively axially moving the concentric control sleeves away from this position, so that the opposed conical surfaces are slightly spaced from one another, there is formed a flow control passage between the concentric control sleeves which, in conjunction with the control openings, permits the controlled flow of fluid between the chambers. Im-position of an external force on the ram caused the piston to move axially through the one chamber to force fluid therefrom through the control openings and the control passage into the other chamber, while permitting the fluid to absorb some of the ram energy due to the restricted fluid flow through the control openings and the control passage. The piston progressively closes off the control openings as it moves axially into said one chamber to thereby also control the energy absorption characteristic of the shock absorber. The quantity of energy absorbed by the shock absorber can be selectively adjusted by causing relative axial displacement between the control sleeves 0 to thereby vary the size of the control passage.
DETAILED DESCRIPTION
R~ferring to Figures 1-4, there is illustrated an energy absorber 10, specifically a hydraulic shock absorber, which in cludes a housing 11 having a ram assembly 12 slidably positioned in and extending therefrom. A flow control sleeve assembly 13 is positioned within the housing for controlling relative move-ment between the housing 11 and the ram assembly 12 due to the imposition of an external load on the shock absorber. The flow control sleeve rneans 13 is adjustable, as explained hereinafter, to permit the quantity of energy absorbed by the shock absorber to be selectively varied.
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The housing 11 includes a hollow cylindrical sleeve 16 fixedly connected between a pair of end members 17 and 18.
The flow control sleeve means 13 includes an inner cylin-drical control sleeve 21 positioned within the housing and ex-tending substantially the full axial length thereof. The sleeve 21 is rotatably received at one end within a bore 22 formed within and extending through the end member 17. The other end of sleeve 21 has a stub shaft 23 fixedly connected thereto, which stub shaft 23 closes off the end of a chamber 27 defined within the control sleeve 21 and projects through an opening 24 formed in the end member 18, whereby stub shaft 23 is rotatably supported on the end member. A retainer ring 26 coacts between stub shaft 23 and end member 18, whereby the stub shaft 23 maintains the sleeve 21 axially fixed with respect to the housing 11.
The ram assembly 12 includes a cup-shap~d piston 28 which is snugly and slidably received within the chamber 27, which piston 28 is connected to an elongated piston rod 29 by a threaded bolt 31. The piston rod 29 is slidably and sealingly support~d by a bushing 39 which is fixedly positioned within the end of sleeve 21.
The bolt 31 and the cup-shaped piston 28 have suitable clearance passages therein for defining a one-way check valve structure to assist in channelling fluid into the chamber 27 when the ram assembly is being extended, that is, being moved leftwardly in Figure 1.
Referring to Figures 3 and 4, the bolt 31 has an inter-mediate cylindrical shank portion 32 which extends through a hole 33 formed in the end wall of the piston 28, which hole is of larger diameter than the shank portion so as to define an annular clearance passage 34 therebetween. The shank portion 32 has a length which is greater than the thickness of the bottom wall of the piston 28 so that the piston 28 can move axially relative to the piston rod 29 between the two positions illustrated in Figures 3 and 4. When the piston 28 is in its outermost position as illustrated in Figure 4, there is thus defined a small clearance space or chamber 36 between the piston and the adjacent end of the piston rod 29, which space 36 com-municates with a pair of grooves 37 which are formed in the piston and extend axially through the free end thereof. The grooves 37 at their rearward (leftward) ends communicate with a chamber 38 which is formed between the piston 28 and the bushing 39 when the ram assembly is displaced inwardly (right-wardly in Figure 1) from its fully extended position. ~he piston 28 also has grooves 35 on the front face thereof which provide communication between the passage 34 and the chamber 27.
As illustrated in Figure 3, when the ram assembly is being contracted (moved rightwardly in Figure 1), the piston 28 is moved into abutting engagement with the free end of the piston rod 29. The intermediate chamber 36 between the piston and the piston rod i5 thus closed off so that passage 34 is isolated from the grooves 37.
The ram assembly 12 has the piston rod 29 thereof projecting outwardly from the housing, which piston rod is provided with an enlarged head 41 fixedly mounted thereon. A compression spring 42 surrounds the piston rod 29 and coacts between the head 41 and a retainer ring 43 for resiliently urging the ram assembly 12 into its outermost or fully extended positlon as illustrated in Figure 1. In this full~ extended position, the piston 28 abuts against the bushing 39, and the piston 28 abuts against the head of the ~5~
bolt 31. While the spring 42 has been illustrated as disposed externally of the housingr it will be appreciated that the spring could be positioned within thehousing if desired.
The flow control sleeve assembly 13 also includes an outer cylindrical control sleeve 46 disposed concentric with and in surrounding relationship to the inner control sleeve 21. The outer sleeve 46 has one end thersof joined to the housing 11, specifically the end member 18, by means of a threaded con-nection 47 which normally maintains the outer control sleeve 46 stationary relative to the housing during normal operation of the shock absorber. However, threaded connection 47 permits the outer sleeve 46 to be rotated relative to the housing when adjustment of the controlsleeve assembly 13 is desired.
The outer control sleeve 46 is, in the illustrated embodi-ment, nonrotatably connected to the inner control sleeve 21 by a pair of pins 48 which as fixed to sleeve 46 and project in-wardly thereform. The pins 48 extend into axially elongated slots 49 formed on diametrically opposite sides of the inner sleeve 21.
This pin-and-slot connection between sleeves 21 and 46 prevents relative rotation therebetween but permits the outer sleeve 46 to be axially displaced relative to the inner sleeve 21 when the complete sleeve assembly 13 is rotated relative to the housing 11.
The control sleeves have opposed conical surfaces formed thereon for controlling the energy absorption characteristic of the shock absorber, and for this purpose the outer control sleeve 46 has an inner conical surface 52 thereon which is disposed op-posite and is adapted to be engaged with an outer conical sur-face 51 as formed on the inner control sleeve 21. The inner and outer conical surfaces 51 and 52, respectively, are of an identi-cal taper, which taper preferably extends at a small angle.
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relative to the longitudinally extending axis A of the shockabsorber. In the illustrated embodiment, the taper of the conical surfaces is normally within the range of between 1 and 5, although the present lnvention also contemplates the use of a larger angle oE taper. The conical surfaces 51 and 52 are maintained in engagement with one another when the sleeve as-sembly 13 is in its fully closed position, in which position the outer sleeve 46 is in its leftwardmost position whereupon the rightward end of sleeve 46 is thus spaced from the end wall of end member 18. However, Figure 1 illustrates the sleeve 46 in its rightwardmost position whereupon the sleeve assembly 13 is in its fully opened condition so that a maximum annular flow pass~ge 53 is formed between the conical surfaces 51 and 52.
This annular flow control passage 53, as formed between the coni-cal surfaces of the control sleeves, communicates with the chamber 27 through an axially extending row of openings 54 as formed in the sidewall of the inner control sleeve 21. The large diameter end of the flow passage 53, that is the leftward end in Figure 1, communicates with a chamber 56 which is formed within the housing 11 in surrounding relationship tothe sleeve assembly 13.
The chamber 56 is in continuous communication with the chamber 38, and for this purpose the end member 17 is provided with a pair of passages or grooves 58 formed therein, which grooves have their rearward ends in communication with openings 59 formed in sleeve 21, which openings communicate with chamber 38.
OPERATIO~
In an operational position, the energy absorber 10 is normally maintained with its ram assembly 12 in an extended position as illustrated in Figure 1 due to the urging of spring ~51~
42. The absorber 10 is filled with fluid, such as hydraulic oil, so that the fluid completely fills at least the chamber 27.
When so prepared, the energy absorber 10 is in condition for engagement by an apparatus from which energy is to be absorbed, which apparatus will move the piston rod inwardly into the housing for decelerating the apparatus or absorbing shock blows therefrom.
When an external load or shock blow is imposed on the ram assembly 12, this causes the piston rod 29 to move inwardly into the housing, which in turn causes inward (rightward) movement of the piston 28. During this rightward movement of the piston, the piston is maintained in the position illustrated in Figure 3 so that the one-way check valve structure formed therein is closed. The inward movement of piston 28 causes pressurization of the fluid contained within the inner chamber 27, which fluid is forced through the openings 54 and through flow passage 53 into the outer chamber 56. As the piston 28 moves axially toward therightward end of the housing, it sequentially closes off the openings 54, which in turn progressively restricts the further flow of fluid from the chamber 27 into the chamber 56. This thus causes the piston 28 to progressively decelerate so that as the piston approaches the inner end of the chamber 27 (rightward end in Figure 1), the external shock load imposed on the shock absorber 10 will be substantially dissipated.
During the inward movement of the ram assembly, as explained above, the chamber 38 as formed behin~ the piston 28 progressively enlarges. This chamber 38 fills with fluid due to its communi-cation with chamber 56 through the passages S8 and openings 59.
When the inward movement of the ram assembly has been stopped and when the external load has been removed from the head portion 41, the ram assembly is returned to its original la)~ 3 extended position due to the urging of the spring 42. During this return movement of the ram assembly, the fluid in chamber 38 causes the piston 28 to be moved rightwardly relative to the piston rod 29 so as to assume the position illustrated in Figure 4, in which position the intermediate chamber 36 is opened so as to permit communication between the passages 34 and 37. This one-way check valve structure as formed by the passages 34-37 thus facilitates the flow of fluid from chamber 38 into chamber 27 as the ram assembly is being returned to its fully extended position. When the ram is fully extended~ the openings 62 ensure that the chamber 21 is completely filled with fluid.
As is understood, the deceleration rate of the ram assembly 12 is determined by the quantity and velocity of the fluid escaping from the inner chamber 27 through the openings 54 and passage 53 into the outer chamber 56. To adjust the deceleration rate of the ram assembly 12, and thereby vary the energy dis-sipating characteristic of the shock absorber 10, the complete sleeve assembly 13 is rotated relativa to the housing 11, which rotation can be accomplished by manually turning the hand wheel 61, which hand wheel could also be mounted on the stub shaft 23 if desired. This rotation of the sleeve assembly 13 causes the outer control sleeve 46 to be axially displaced relative to the inner sleeve 21 due to the threaded connection 47. Since the sleeve assembly can be rotated through an arcuate distance equal to severai complete revolutions, this thus permits a very fineand precise adjustment in terms of the axial displacement of the outer sleeve 46 relative to the inner sleeve 21, which axial adjustme~t in turn varies the radial spacing between the conical surfaces 51 and 52 and hence varies the cross-sectional area of the annular flow passage 53.
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MODIFICATION
Figures 5-8 illustrate therein a preferred embodiment of the invention which incorporates therein many of the structural and operational features possessed by the shock absorber 10 of Figures 1-4. Accordingly, the parts of the shock absorber il-lustrated in Figures 5~8 have been designated by the same reference numerals used to designate corresponding parts of the shock absorber illustrated in Figures 1-4 except that the reference numerals have been increased by 100.
In the shock absorber 110, the inner control sleeve 121 extends between and is supported on the end members 117 and 118, and the outer control sleeve 146 is disposed concentric with and in surrounding relationship to the inner sleeve 121. Outer sleeve 146 has an inner conical surface 152 thereon which is disposed opposite the outer conical surface 151 formed on the inner sleeve 121, which conical surfaces are adapted to be slightly spaced apart so as to provide a flow control passage 153 therebetween.
In this embodiment, the inner control sleeve 121 is pro-vided with a pair of elongated slots 171 (Figures 6 and 7) formed in the outer conical surface 151, which slots 171 extend axially of the sleeve 121 throughout the length of the outer sleeve 146 and terminate in openings 171A (Figure 8) which communicate with the outer chamber 156. The slots 171 are disposed closely adjacent and on opposite sides of the axially extending row of openings 154, whereby the slots result in the formation of narrow circumferentially extending lands 172 between the row of openings 154 and the adjacent slots 171. These lands 172 are spaced from the opposed inner conical surfac~ 152 and thus define narrow con-trol passages 173 therebetween for controlling the fluid flow ~)58Z2~
from the openings 154 into the slots 171.
The slots 171 are formed in the sleeve 121, as by a milling cutter, such that the bottom wall of each slot extends substan-tially parallel to the axis A. This results in the cross-sectional area of each slot 171 progressively increasing as the slot extends from the inner or rightward end thereof to the outer or leftward end thereof as illustrated in Figure 8. The slot 171 is thus effectively of zero cross-sectional area at the rightward end of the control sleeve 146, whereas the slot 171 progressively increases in cross-sectional area so as to have a maximum cross-sectional area adjacent the leftward end of the control sleeve 146.
While Figures 6 and 7 illustrate the use of two slots 171, with one being positioned on each side of the row of openings 154, it will be appreciated that the shock absorber 110 could be provided with only a single slot 171 if desired.
The outer control sleeve 146 is axially adjustable relative to the inner control sleeve 121 so as to vary the radlal width or dimension or the passages 153 and 173. For this purpose, shock absorber 110 is provided with an adjustment means 114 which includes a knob or handle 176 fixedly secured to the outer end of a control shaft 177, which control shaft is in turn rotatably and sealingly supported on a housing hub 178 so that the control shaft 177 is rotatable about an axis which extends substantially perpendicular to the axis A. Control shaft 177 has a cam or eccentric 179 fixedly secured to the inner end thereof, which eccentric 179 is engaged with an opening or slot 181 formed in the outer control sleeve 146. The eccentric 179 is preferably of circular cross-section and has the axis thereof eccentrically displaced from the axis of the shaft 177, whereby eccentric 179 functions like a crankpin. The slot 181 has a ~5~
width, as measured in the axial direction of the control sleeve, which substantially corresponds to the diameter of the eccen-tric 179 so that the eccentric is snugly accommodated therein.
However, the length of the slot 181, as measured circumferenti-ally of the control sleeve, is preferably greater than the diameter of the eccentric to thereby compensate for the sideward displacement of the eccentric during rotation of the control shaft 177.
The control shaft 177 is rotatable through a maximum angle of 180, and preferably less, so as to cause a corresponding rotation of the eccentric 179, which in turn causes axial dis-placement of control sleeve 146 between two endmost positions~
When the adjustment mechanism is in the position illustrated in Figure 5, in which position the eccentric is in its leftward end position, the outer control sleeve 146 effectively abuts against a stop 182 as formed on the inner control sleeve 121, thereby resulting in a minimum clearance between the conical surfaces 151 and 152 so that the openings 154 are effectively closed. The presence of the stop 182, however, prevents the two conical surfaces 151 and 152 from being lockingly wedged to-gether. When the controlknob 176 and eccentric 179 are rotated away from the position illustrated in Figure 5, then the outer control sleeve 146 is moved axially rightwardly so that the spacing 153 between the conical surfaces 151 and 152 is in-creased, with the maximum spacing 153 existing when the end of sleeve 146 abuts against the stop surface 188. Rotation of knob 176 thus permits the spacing 153 between the conical sur-faces 151 and 152 to be selectively varied and adjusted so as to provide for the desired restricted flow of fluid from the inner chamber 127 into the outer chamber 156 when the ram assembly 112 ~,~5~fæ~
is moved inwardly into the housing 111.
The shock absorber can be suitably locked in its selected position by means of a set screw 183 which locks the knob 176 to the hub 178 and thereby fixedly maintains the positional relationship between the control sleeves 121 and 146.
The housing has a port 186 associated therewith for per-mitting filling of the shock absorber with fluid, such as hydraulic oil. After filling, the port 186 is normally closed by means of a conventional plug.
When an external load or shock force is imposed on the ram assembly 112, the piston 128 moves inwardly (rightwardly) into the compartment 127, thereby forcing fluid outwardly through the openings 154. The fluid then flows over the land 172 into the slots 171, since this is the path of least flow resistance. The fluid then flows along the slots 171 and discharges through the ends 171A thereof into the outer chamber 156. The restriction imposed on the fluid flow by the openings 154 and control pas-sages 173 thus absorbs the energy of the apparatus which is impacting against the ram assembly, and accordingly caused a deceleration of the ram assembly.
As the ram assembly moves further into the compartment 127, the piston 128 progressively closes off the openings 154 so that the flow of fluid from chamber 127 into chamber 156 is further progressively restricted, thereby causing a progressive deceleration of the ram assembly as it approaches the rightward end of the shock absorber. This progressive closing of the openings 154, coupled with the flow passage 173 formed between the openings 154 and the slots 171, thus causes a very uniform deceleration and stopping of the ram assembly. Further, since the grooves 171 are of progressively increasing cross-sectional ~5~Z~
area, they readily accommodate the variable flow therethrough depending upon the number of openings 154 which are uncovered.
For example, when the pi.ston 128 is adjacent the leftward end of the shock absorber, a large number of openings 154 are un-covered so that fluid will flow through the openings 154 into the slots 171 along substantially the complete length thereof, whereupon a large quantity of fluid will flow into the slots for passage into the outer chamber 156. This larger quantity of fluid is permitted since the cross-sectional area of the slots 171 progressively increases towards the discharge end of theslots in correspondence with the progressive spac-ing of the openings axially along the inner control sleeve.
On the other hand, when the piston 128 is more closely adja-cent the rightward end of the shock absorber, only a few open-ings 154 are uncovered so that a substantially smaller quan-tity of fluid flows into the slots 171 for discharge into the outer chamber 176.
It will be appreciated that the adjustment mechanism 114 could be replaced with other suitable mechanisms capable of causing the desired axial movement between the sleeves 121 and 146.
Figure 9 illustrates an energy absorber 210, specifically a hydraulic shoc~ absorber, which includes a housing 211 having a ram assembly 212 slidably positioned in and extend-ingtherefrom. A flow control sleeve assembly 213 is posi-tioned within the housing for controlling relative movement between the ram assembly 212 and the housing 211 due to imposition of an external load on the shock absorber. The flow control sleeve assembly 213 is adjustable, as explained hereinafter, to permit the quantity of energy absorbed to be selectively varied.
The housing 211 includes a hollow cylindrical sleeve 216 fixedly connected between a pair of end members 217 and 218~
The flow control sleeve assembly 213 includes an inner cylindrical control sleeve 219 positioned within the housing and extending substantially the full axial length thereof.
The sleeve 219 is fixed with respect to the housing and has the rightward end thereof pressed onto a member 221 which abuts against the end member 217~ The leftward end of sleeve 219 is snugly seated on an annular projection 222 which extends inwardly from a bearing sleeve 222 which is fixedly and sealingly mounted on the other end member 218.
A conical wall 223 is formed on the inner edge of the left-ward end of sleeve 219, and a conventional elastomeric O-ring 224 is clampingly engaged between the wall 223 and the corner defined on the end member 218 to create a sealed re-lationship therebetween. Thisstructure overcomes any pro-blem caused during the assembly of the shock absorber dueto the accumulation of axial tolerances on the individual parts, whereby the individual parts can be manufactured with less stringent tolerances and a-t the same time permit a more efficient assembly of the shock absorber.
As an alternative, the leftward end of sleeve 219 can have an annular recess 223' formed therein, as shown in Figure 14, so as to accommodate the O-ring 224'.
The ram assembly 212 has a substantially cylindrical piston 226 on the inner end thereof, which piston is dis-posed within a chamber 227 defined within the inner control sleeve 219 and is slidably guided for axial movement there-along. The piston 226 is fixedly secured on the inner end of a piston rod 228. The piston rod has a reduced dia-meter portion for accommodating the piston thereon, which piston abuts against a shoulder 229 formed on the rod 228.
The piston 226 and piston rod 228 have aligned holes 231A
and 231B (Figure 13) extending diametrically thereacross, which holes receive therein an elongated axially split spring pin 232. The pin 232 expands circumferentially to be snugly accommodated within the holes 231A-231B so as to fixedly interconnect the piston and the piston rod.
The piston 226 has an annular groove 233 extending therearound, which groove communicates with the holes 231.
A conventional annular split piston ring 234 may, if neces~
sary, be disposed in the groove 233 to create a slidable sealed engagement with the inner wall of the sleeve 21g.
Piston ring 234 also retains the spring pin 232 within the holes 231.
A one-way check valve assembly 236 is associated with the inner end of the ram assembly, particularly the piston 226. This check valve assembly 236, as shown in Figures 9 and 13, includes a first passage formed as a large diametex bore 237 extending coaxially inwardly from the inner free end of the piston rod 228. This bore 237 in turn communicates with and is coaxially aligned with a further passage formed as a small diameter bore 238. A further passage 239 extends radially of the piston rod adjacent the rear face of the piston and communicates with the bore 238 adjacent the axially inner end thereof. The radially outer end of transverse passage 239 communicates with a chamber 2~1 ~5~
which is formed within the sleeve 219 and is located between the opposed axial faces of the piston 226 and the end hub 222A when the piston 226 is moved slightly inwardly away from the end hub as shown in Figure 9.
To control flow through the passage arrangement defined by the passages 237, 238 and 239, there is provided a movable valve member in the form of a ball 243 which is adapted to seat against an annular conical valve seat 242 formed at the junction between the bores 237 and 238. The ball 2g3 is disposed in the large bore 237 and is of a larger diameter than the bore 238. The ball 243 is confined in the bore 237 by the locking pin 232 which extends diametrically across the bore 237 but is spaced axially a small distance from the ball 243 to permit movement of the ball away from the seat 242 so as to permit flow through the passage arrangement.
The inner control sleeve 219 has small holes247 formed through the wall thereof and communicating at the radially outer ends with an outer annular chamber 246 formed between the sleeve assembly 213 and the outer housing sleeve 216.
The holes 247 are disposed adjacent the leftward end of the sleeve 219, which end has the piston 226 associated there-with when the shock absorber is in its extended position.
The holes 247 are positioned directly adjacent the inner axial face of the hub 222A so that the holes thus communicate with the chamber 241 at all times. One of the holes 247 has the radially inner end thereof joined in flow communica-tion with an axially extending groove 248 formed in the inner wall of the sleeve 219, which groove 248 terminates at a location which is disposed slightly forwardly of the front face of the piston 226 when the ram assembly is in its ~s~
fully extended position.
The flow control sleeve assembly 213 also includes an outer cylindrical control sleeve 251 disposed concentric with and in surrounding relationship to the inner conrol sleeve 219.
The outer sleeve 251 has the rightward end thereof axially spaced from the end member 217, whereby outer sleeve 251 can thus be moved axially through a limited extent relative to the inner sleeve 219.
The control sleeves 219 and 251 have opposed conical surfaces formed thereon for permitting adjustment in the energy absorption characteristic of the shock absorber~
For this purpose, the outer control sleeve 251 has an inner conical surface 253 which is disposed opposite and is adapted to be engaged with an outer conical surface 2~4 as formed on the inner control sleeve 219. The conical surfaces 253 and 254 are of an identical taper, which taper preferably extends at a small angle relative to the longitudinally ex-tending axis A of the shock absorber. In the illustrated embodiment, the taper of the conical surfaces is normally in the range of between 1 and 5, and preferably 2, al-through the present invention also contemplates the use of a larger angle of taper. The conical surfaces 253 and 254 are maintained substantially in engagement with one another when the sleeve assembly 213 is in its fully closed posi-tion, in which position the outer sleeve 251 is in its left-ward most position.
To provide for controlled flow of fluid from the inner chamber 227 through the sleeve assembly 213 to the outer chamber 246, which controlled flow permits the absorption of energy when a shock load is imposed on the absorber, z~
the inner and outer control sleeves are relatively moved into a position in which the opposed conical surfaces 253 and 254 are spaced a small distance apart so as to result in the formation of a small annular space 256 therebetween.
The inner control sleeve 219 is provided with a pair of elongated slots 257 (Figures 10-12) formed in the outer conical surface 254 thereof~ which slots 257 extend axially of the sleeve 219 throuyhout substantially the complete length of the outer sleeve 251. The slots 257 terminate, at the leftward ends thereof, in openings 258 (Figure 12) which communicate with the outer chamber 2~6. The slots 257 are disposed closely adjacent and on opposite sides of an axially extending row of openings 261 which are formed in the inner sleeve 219 and communicate with the inner chamber 227. The slots 257 and their relationship to the row of openings 261 results in the formation of narrow circum-ferentially extending lands 262 between the row of openings 261 and the adjacent slots 257. The lands 262 are adapted to be spaced from the opposed inner conical surface 253 and thus define narrow flow control passages 263 therebetween for controlling the fluid flow from the openings 261 into the slots 257.
The outer control sleeve 251 is axially adjustable re-lative to the inner control sleeve 219 so as to vary the radial width or dimension of the passages 256 and 263. For this purpose, there is provided an adjustment structure 266 which includes a knob or handle 267 fixedly secured to the outer end of a control shaft 268, which control shaft is in turn rotatably and sealingly suppor-ted on a housing hub 269 so that the control shaft is rotatable about an axis ~(~SB~Z91 which extends substantially perpendicular to the axis A.
Control shaft 268 is axially restrained with respect to the housing hub 269 by means of a locking pin 271. Control shaft 268 has a cam or eccentric 272 fixedly secured to the inner end thereof, which eccentric is disposed within an opening or slot 273 formed in the outer control sleeve 251. The eccentric 272 is preferably of circular cross-section and has the axis thereof eccentrically displaced from the axis of the shaft 268, whereby eccentric 272 func-tions like a crankpin. The slot 273 has a width, as mea-sured in the axial direction of the control sleeve 251, which substantially corresponds to the diameter of the eccentric 272 so that same is snugly accommodated in the slot.
However, slot 273 has a length, as measured circumferentially of the control sleeve, which is preferably greater than the diameter of the eccentric to thereby compensate for the side-ward displacement of the eccentric during rotation of the control shaft 268.
The control shaft 268 is rotatable through an angle of approximately 180, and preferably slightly less, so as to cause a corresponding rotation of the eccentric 272, which in turn causes axial displacement of outer control sleeve 251 between two endmost positions. When the adjust-ment structure is in the position illustrated in Figure 9, in which position the eccentric 272 is in its leftward end position, the outer control sleeve 251 effectively abuts against a stop 274 (Figure 12) as formed on the inner control sleeve 219, thereby resulting in a minimum clearance between the conical surfaces 253 and 254 so that the open-ings 261 are effectively closed. The presence of the stop ~5~2'~1 274, however, prevents the two conical surfaces 253 and 254 from being lockingly wedged together.
When the control knob 267 and eccentric 272 are rotated away from the position illustrated in Figure 9, then the outer control sleeve 251 is moved axially rightwardly so that the spacing 256 between the conical surfaces 253 and 254 is increased, with the maximum spacing existing when the sleeve 251 is in its rightward most position.
Rotation of knob 267 thus permits the spacing between the conical surfaces to be selectively varied and adjusted to provide for the desired restricted flow of fluid from the inner chamber 227 into the outer chamber 246 when the ram assembly 212 is moved inwardly into the housing 211.
The shock absorber can be suitably locked in its select-ed position by means of a set screw 276 which locks the knob 267 to the housing hub 269 and thereby fixedly maintains the positional relationship between the control sleeves 219 and 251. Set screw 276 is positioned substantially parallel to the axis of the control shaft 268 and thus projects per-pendicularly from the side of the housing so as to be readily accessible for adjustment, as by means of an Allen wrench or other tool.
The ram assembly 212 has an enlarged head 278 on the outer free end of the piston rod 228, which head 278 is adapted to have the shock loads imposed thereon, and a conventional compression spring 279 surrounds the piston rod 228 and is confined between the head 278 and the bushing 222 to thereby continuously urge the ram assembly into its outward extended position.
Housing 211 has a port 281 associated therewith to permit the shock absorber to be filled with fluid, such as hydraulic oil. This port is normally closed by means of a conventional plug. Chamber 246 also preferably has a compressible spongelike member 282 positioned therein so as to compensate for volume changes caused by the inward movement of the piston rod, which member 282 substantially encircles the sleeve 251 throughout the axial extent thereof. The member 282 is preferably of a rubber or plastic closed-cell structure.
The operation of the embodiment shown in ~igures 9-13 is believed readily apparent from the above structural and operational descriptions.
Claims
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
In a fluid-type energy absorber having a housing, ram means slidably disposed on the housing for receiving a shock load thereon, the ram means including a piston slidably disposed within the housing and connected to a piston rod which extends outwardly from the housing, the piston being normally maintained adjacent one end of the housing, a first sleeve member disposed within the housing and coacting with the piston for forming first and second fluid chambers which are effectively separated from one another, the piston being slidably and sealingly engaged with the first sleeve member, the first fluid chamber being defined at least in part by the first sleeve member and extending between the piston and the other end of said housing, and flow passage means for providing limited fluid flow from said first chamber into said second chamber responsive to axial displace-ment of said piston into said first chamber, said flow passage means including opening means extending radially through the wall of said first sleeve member and extending axially over a substantial portion of the length of said first chamber, the improvement comprising control means coacting with said sleeve member and said flow passage means for controlling the flow from said first chamber to said second chamber, said control means including a second sleeve member disposed concentric with said first sleeve member and positioned so that said first sleeve member is disposed between said piston and said second sleeve member, said first and second sleeve members having opposed conical Claims, Page 1 surfaces thereon which are disposed closely adjacent and directly opposite so as to define a narrow flow passage-way therebetween, said narrow fluid passageway being in communication with said opening means and comprising a part of said flow passage means, and said flow passage means including elongated groove means formed in the coni-cal surface of one of said sleeve members and extending substantially axially of said one sleeve member for communication at one end thereof with said second fluid chamber, said groove means being adjacent but circumfer-entially displaced by a preselected distance from said opening means and communicating therewith by said narrow flow passageway, whereby said narrow flow passage-way restricts the flow of fluid from said opening means to said groove means whereby the flow from said first cham-ber to said second chamber is thereby controlled.
An energy absorber according to Claim 1, wherein said second sleeve member in the arcuate extent thereof between said opening means and said groove means is free of openings extending radially through the wall thereof, and wherein said groove means has a radial depth less than the radial thickness of the wall forming said one sleeve member.
An energy absorber according to Claim 2, wherein said groove means includes a pair of substantially parallel grooves extending axially of said one sleeve member, said grooves being circumferentially displaced said preselected distance on opposite sides of said opening means.
Claims, Page 2 An energy absorber according to Claim 2, wherein said groove means is formed in said first sleeve member and communicates with the conical surface formed on said first sleeve member.
An energy absorber according to Claim 4, wherein said piston is slidably disposed within said first sleeve member, wherein said first chamber is defined within said first sleeve member and extends axially between said piston and the other end of said housing, and wherein said second sleeve member surrounds said first sleeve member.
An energy absorber according to Claim 1, wherein said second chamber includes at least a portion thereof disposed between said piston and said one end of the housing as said piston moves inwardly into said first chamber in response to application of an external load on said ram means, and one-way check valve means associated with said piston for providing flow from said portion into said first chamber as said piston is being moved toward said one end of said housing, said one-way check valve means preventing flow therethrough from said first chamber directly into said portion when said piston is being moved toward the other end of said housing In an energy absorber according to Claim 6, wherein said second chamber includes a second portion disposed between said first sleeve member and said housing, said second portion being annular and positioned in surrounding Claims, Page 3 relationship to said first sleeve member, said first sleeve member having connecting passage means formed therein for providing communication between said first-mentioned portion and said second portion, and further passage means providing direct communication between said first and second chambers only when said piston is in its fully retracted position and is disposed adjacent said one end of said housing, said fur-ther passage means including a flow passage formed in said first sleeve member and communicating with said first chamber directly adjacent the face of said piston when the latter is in its fully retracted position.
An energy absorber according to Claim 1, including ad-justment means for causing relative axial displacement be-tween said first and second sleeve members for selectively varying the size of the narrow flow passageway defined between said conical surfaces, said adjustment means including locking means associated therewith for selectively fixedly securing the first and second sleeve members in a selected axial position with respect to one another.
An energy absorber according to Claim 1, wherein said opening means includes a plurality of openings which ex-tend radially through said first sleeve member and are axially spaced a preselected distance apart along a row which extends axially of said first sleeve member, wherein said groove extends axially parallel to said row and is cir-cumferentially displaced therefrom, and wherein said groove is of progressively increasing cross-sectional area as it extends toward an end of the respective conical surface, the end of said groove which is of largest cross-sectional area being in communication with said second chamber.
Claims, Page 4 An energy absorber according to Claim 1, including adjust-ment means for causing relative axial displacement between said first and second sleeve members for selectively varying the size of the flow passageway therebetween, said adjustment means including a control shaft rotatably supported on said housing for rotation about an axis substantially perpendicular to the longitudinally extending axis of said sleeve members, said control shaft extending exteriorly of said housing and having manually engageable handle means thereon, and eccentric means mounted on said control shaft adjacent the inner end thereof and disposed in engagement with an opening formed in one of said sleeve members for causing axial displacement thereof in response to angular displacement of said control shaft.
An energy absorber according to Claim 10 wherein said second sleeve member is disposed exteriorly of and surrounds said first sleeve member, wherein said first sleeve member is axially fixed with respect to said housing, and wherein said eccentric is disposed in engagement with said second sleeve member for moving same axially along said first sleeve member.
An energy absorber according to Claim 1, wherein said first fluid chamber is defined within the interior of said first sleeve member and said second fluid chamber is defined between said first sleeve member and said housing, a third fluid chamber formed directly behind said piston when same is moving in a first direction away from said one end of said Claims Page 5 housing, said third chamber being in continuous communication with said second chamber, one-way check valve means associated with said piston for permitting fluid flow therethrough from said third chamber into said first chamber when said piston is moving axially of said one chamber in a second direction which is opposite said first direction, said one-way check valve means preventing flow of fluid from said first chamber directly into said third chamber when said piston is moving in said first direction, and passage means for providing direct and conti-nuous communication between said third chamber and said first chamber only when said piston is disposed in a position closely adjacent said one end of said housing, said passage means being independent of said one-way check valve means.
An energy absorber according to Claim 12, wherein said passage means comprises a passage formed in and extending axially of one of said sleeve members, said passage being of sufficient axial length so that the opposite axial ends thereof communicate with said first and third chambers when said piston is adjacent said one end of said housing, said piston when moved away from said one end isolating said passage from said first chamber.
An energy absorber according to Claim 1, where the piston is of annular configuration and surrounds and is fixedly con-nected to an end of the piston rod by a pinlike locking member which extends diametrically across and interconnects the piston and the end of the piston rod, said rod end and said piston having aligned openings extending diametrically therethrough and accommodating said locking member therein, and one-way Claims Page 6 valve means associated with and extending axially through said piston for permitting flow from one side to the other side of said piston in response to axial movement thereof in one direction, said rod end having an opening formed therein and extending axially of the rod through a distance greater than the axial length of said piston, said opening having a valve member positioned therein, and said locking member extending across said opening for confining said valve member therein.
An energy absorber according to Claim 14, wherein said piston also has an annular groove formed around the outer circumferential periphery thereof, the bottom of said groove communicating with the diametrical opening in said piston, and a split piston ring disposed within said annular groove and surrounding said piston, said piston ring being disposed in sliding sealed engagement with said housing.
Claims Page 7 End of Claims
In a fluid-type energy absorber having a housing, ram means slidably disposed on the housing for receiving a shock load thereon, the ram means including a piston slidably disposed within the housing and connected to a piston rod which extends outwardly from the housing, the piston being normally maintained adjacent one end of the housing, a first sleeve member disposed within the housing and coacting with the piston for forming first and second fluid chambers which are effectively separated from one another, the piston being slidably and sealingly engaged with the first sleeve member, the first fluid chamber being defined at least in part by the first sleeve member and extending between the piston and the other end of said housing, and flow passage means for providing limited fluid flow from said first chamber into said second chamber responsive to axial displace-ment of said piston into said first chamber, said flow passage means including opening means extending radially through the wall of said first sleeve member and extending axially over a substantial portion of the length of said first chamber, the improvement comprising control means coacting with said sleeve member and said flow passage means for controlling the flow from said first chamber to said second chamber, said control means including a second sleeve member disposed concentric with said first sleeve member and positioned so that said first sleeve member is disposed between said piston and said second sleeve member, said first and second sleeve members having opposed conical Claims, Page 1 surfaces thereon which are disposed closely adjacent and directly opposite so as to define a narrow flow passage-way therebetween, said narrow fluid passageway being in communication with said opening means and comprising a part of said flow passage means, and said flow passage means including elongated groove means formed in the coni-cal surface of one of said sleeve members and extending substantially axially of said one sleeve member for communication at one end thereof with said second fluid chamber, said groove means being adjacent but circumfer-entially displaced by a preselected distance from said opening means and communicating therewith by said narrow flow passageway, whereby said narrow flow passage-way restricts the flow of fluid from said opening means to said groove means whereby the flow from said first cham-ber to said second chamber is thereby controlled.
An energy absorber according to Claim 1, wherein said second sleeve member in the arcuate extent thereof between said opening means and said groove means is free of openings extending radially through the wall thereof, and wherein said groove means has a radial depth less than the radial thickness of the wall forming said one sleeve member.
An energy absorber according to Claim 2, wherein said groove means includes a pair of substantially parallel grooves extending axially of said one sleeve member, said grooves being circumferentially displaced said preselected distance on opposite sides of said opening means.
Claims, Page 2 An energy absorber according to Claim 2, wherein said groove means is formed in said first sleeve member and communicates with the conical surface formed on said first sleeve member.
An energy absorber according to Claim 4, wherein said piston is slidably disposed within said first sleeve member, wherein said first chamber is defined within said first sleeve member and extends axially between said piston and the other end of said housing, and wherein said second sleeve member surrounds said first sleeve member.
An energy absorber according to Claim 1, wherein said second chamber includes at least a portion thereof disposed between said piston and said one end of the housing as said piston moves inwardly into said first chamber in response to application of an external load on said ram means, and one-way check valve means associated with said piston for providing flow from said portion into said first chamber as said piston is being moved toward said one end of said housing, said one-way check valve means preventing flow therethrough from said first chamber directly into said portion when said piston is being moved toward the other end of said housing In an energy absorber according to Claim 6, wherein said second chamber includes a second portion disposed between said first sleeve member and said housing, said second portion being annular and positioned in surrounding Claims, Page 3 relationship to said first sleeve member, said first sleeve member having connecting passage means formed therein for providing communication between said first-mentioned portion and said second portion, and further passage means providing direct communication between said first and second chambers only when said piston is in its fully retracted position and is disposed adjacent said one end of said housing, said fur-ther passage means including a flow passage formed in said first sleeve member and communicating with said first chamber directly adjacent the face of said piston when the latter is in its fully retracted position.
An energy absorber according to Claim 1, including ad-justment means for causing relative axial displacement be-tween said first and second sleeve members for selectively varying the size of the narrow flow passageway defined between said conical surfaces, said adjustment means including locking means associated therewith for selectively fixedly securing the first and second sleeve members in a selected axial position with respect to one another.
An energy absorber according to Claim 1, wherein said opening means includes a plurality of openings which ex-tend radially through said first sleeve member and are axially spaced a preselected distance apart along a row which extends axially of said first sleeve member, wherein said groove extends axially parallel to said row and is cir-cumferentially displaced therefrom, and wherein said groove is of progressively increasing cross-sectional area as it extends toward an end of the respective conical surface, the end of said groove which is of largest cross-sectional area being in communication with said second chamber.
Claims, Page 4 An energy absorber according to Claim 1, including adjust-ment means for causing relative axial displacement between said first and second sleeve members for selectively varying the size of the flow passageway therebetween, said adjustment means including a control shaft rotatably supported on said housing for rotation about an axis substantially perpendicular to the longitudinally extending axis of said sleeve members, said control shaft extending exteriorly of said housing and having manually engageable handle means thereon, and eccentric means mounted on said control shaft adjacent the inner end thereof and disposed in engagement with an opening formed in one of said sleeve members for causing axial displacement thereof in response to angular displacement of said control shaft.
An energy absorber according to Claim 10 wherein said second sleeve member is disposed exteriorly of and surrounds said first sleeve member, wherein said first sleeve member is axially fixed with respect to said housing, and wherein said eccentric is disposed in engagement with said second sleeve member for moving same axially along said first sleeve member.
An energy absorber according to Claim 1, wherein said first fluid chamber is defined within the interior of said first sleeve member and said second fluid chamber is defined between said first sleeve member and said housing, a third fluid chamber formed directly behind said piston when same is moving in a first direction away from said one end of said Claims Page 5 housing, said third chamber being in continuous communication with said second chamber, one-way check valve means associated with said piston for permitting fluid flow therethrough from said third chamber into said first chamber when said piston is moving axially of said one chamber in a second direction which is opposite said first direction, said one-way check valve means preventing flow of fluid from said first chamber directly into said third chamber when said piston is moving in said first direction, and passage means for providing direct and conti-nuous communication between said third chamber and said first chamber only when said piston is disposed in a position closely adjacent said one end of said housing, said passage means being independent of said one-way check valve means.
An energy absorber according to Claim 12, wherein said passage means comprises a passage formed in and extending axially of one of said sleeve members, said passage being of sufficient axial length so that the opposite axial ends thereof communicate with said first and third chambers when said piston is adjacent said one end of said housing, said piston when moved away from said one end isolating said passage from said first chamber.
An energy absorber according to Claim 1, where the piston is of annular configuration and surrounds and is fixedly con-nected to an end of the piston rod by a pinlike locking member which extends diametrically across and interconnects the piston and the end of the piston rod, said rod end and said piston having aligned openings extending diametrically therethrough and accommodating said locking member therein, and one-way Claims Page 6 valve means associated with and extending axially through said piston for permitting flow from one side to the other side of said piston in response to axial movement thereof in one direction, said rod end having an opening formed therein and extending axially of the rod through a distance greater than the axial length of said piston, said opening having a valve member positioned therein, and said locking member extending across said opening for confining said valve member therein.
An energy absorber according to Claim 14, wherein said piston also has an annular groove formed around the outer circumferential periphery thereof, the bottom of said groove communicating with the diametrical opening in said piston, and a split piston ring disposed within said annular groove and surrounding said piston, said piston ring being disposed in sliding sealed engagement with said housing.
Claims Page 7 End of Claims
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/608,885 US4026533A (en) | 1975-08-29 | 1975-08-29 | Shock absorber with conical control elements |
| US05/686,585 US4057236A (en) | 1975-08-29 | 1976-05-14 | Energy absorber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1058229A true CA1058229A (en) | 1979-07-10 |
Family
ID=27085901
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA259,308A Expired CA1058229A (en) | 1975-08-29 | 1976-08-18 | Energy absorber with conical control elements |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1058229A (en) |
-
1976
- 1976-08-18 CA CA259,308A patent/CA1058229A/en not_active Expired
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