Compact shock absorber

• US 4,690,255 A
• Filed: 03/10/1986
• Issued: 09/01/1987
• Est. Priority Date: 03/10/1986
• Status: Expired due to Term

• Current Assignee: ACE Controls Inc. (Stabilus S.A.)
• Original Assignee: Econtrols Incorporated
• Inventors: Heideman, Robert J.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/838,267
• Time in Patent Office: 540 Days
• Field of Search: 188/285, 188/287, 188/299, 188/315, 188/322.19
• US Class Current: 188/287
• CPC Class Codes: F16F 9/44 Means on or in the damper for manual or non-automatic adjustment; such means combined with temperature correction F16F9/53, F16F13/26 take precedence; temperature correction only F16F9/52

Abstract

A shock absorber including an inner tube closed at its rearward end and open at its forward end and having a plurality of ports formed at longitudinally spaced locations along its side wall, a piston rod and piston head assembly slidably received in the inner tube with the rearward end of the piston head spaced from the closed rearward end of the inner tube and the piston rod projecting forwardly out of the open forward end of the inner tube for impact by a moving object, an outer tube comprising the outer casing of the shock absorber and surrounding the inner tube, a plurality of longitudinally spaced interior grooves in the outer tube respectively registering with the ports in the inner tube and skewed with respect to the longitudinal axis of the shock absorber, and an annular accumulator chamber defined forwardly of the inner tube between the inner periphery of the outer tube and the outer periphery of the piston rod. A pair of longitudinally extending flats are provided at diametrically spaced locations on the exterior surface of the inner tube and these flats coact with the adjacent inner periphery of the outer tube to define a pair of longitudinal passages for routing the cushioning fluid from the interior grooves of the outer tube axially forwardly to the accumulator chamber so as to complete the closed fluid loop within the shock absorber.

Claims

1. In a shock absorber of the type including an inner tube closed at closed at its rearward end and open at its forward end;

a piston rod and piston head assembly slidably received in the inner tube with the rearward end of the piston head spaced from the closed rearward end of the inner tube and the piston rod projecting forwardly out of the open forward end of the inner tube for impact by a moving object;

an outer tube surrounding the inner tube;

a cushioning fluid substantially filling the shock absorber;

metering means in the inner tube coating with metering means in the outer tube to define a plurality of metering orifices; and

adjusting means providing relative movement between the inner and outer tubes and operative in response to such relative movement to selectively vary the respective relative positions of the metering means in the inner tube relative to the coacting respective metering means in the outer tube to thereby vary the size of the metering orifices and thereby selectively vary the impact resistance generated by the movement of the cushioning fluid through the metering orifices in response to impacting movement of the piston assembly toward the closed rearward end of the inner tube;

the improvement wherein;

(A) an annular accumulator chamber is provided in said shock absorber radially outwardly of said piston assembly at a longitudinal location forwardly of said metering orifices; and

(B) means are provided for routing cushioning fluid from said metering orifices axially forwardly between said inner and outer tubes to said annular accumulator chamber.

2. A shock absorber according to claim 1 wherein:

(C) said outer tube comprises the outer casing of said shock absorber and extends to a location forwardly of said inner tube; and

(D) said accumulator chamber is defined forwardly of said inner tube between the forward extension of said outer tube and said piston assembly.

3. A shock absorber according to claim 1 wherein:

(C) said coacting means in said tubes comprises

(1) a plurality of ports in said inner tube at longitudinally spaced locations along its side wall, and

(2) a plurality of longitudinally spaced interior grooves in said outer tube respectively registering with said ports in said side wall of said inner tube and skewed with respect to the longitudinal axis of the shock absorber; and

(D) said adjusting means comprises means providing relative rotation between said tubes to selectively vary the magnitude of the registration between said ports and said grooves.

4. A shock absorber according to claim 1 wherein:

(C) said routing means comprises at least one longitudinal passage defined between said tubes and extending forwardly from a location adjacent the rearmost metering orifice to said accumulator chamber.

5. A shock absorber according to claim 4 wherein:

(D) said coacting means in said tubes comprises

(1) a plurality of ports in said inner tube at longitudinally spaced locations along its side wall, and

(2) a plurality of longitudinally spaced interior grooves in said outer tube respectively registering with said ports in said side wall of said inner tube and skewed with respect to the longitudinal axis of the shock absorber; and

(E) said adjusting means comprises means providing relative rotation between said tubes to selectively vary the magnitude of the registration between said ports and said grooves.

6. A shock absorber according to claim 5 wherein:

(F) said longiudinal passage intersects each of said grooves as it extends forwardly to said accumulator chamber.

7. A shock absorber according to claim 6 wherein:

(G) said ports lie generally along a straight line parallel to said axis; and

(H) said passage is angularly displaced relative to said ports.

8. In a shock absorber of the type including an inner tube closed at closed at its rearward end and open at its forward end;

a piston rod and piston head assembly slidably received in the inner tube with the rearward end of the piston head spaced from the closed rearward end of the inner tube and the piston rod projecting forwardly out of the open forward end of the inner tube for impact by a moving object;

an outer tube surrounding the inner tube;

a cushioning fluid substantially filling the shock absorber;

means in the inner an outer tubes cooperating to define a plurality of metering orifices; and

adjusting means for providing relative movement between the tubes to selectively vary the size of the metering orifices and thereby selectively vary the impact resistance generated by the movement of the cushioning fluid through the metering rifices in response to impacting movement of the piston assembly toward the closed rearward end of the inner tube;

the improvement wherein;

(A) an annular acculumator chamber is provided in said shock absorber radially outwardly of said piston assembly at a longitudinal location forwardly of said metering orifices;

(B) means are provided for routing cushioning fluid from said orifices axially forwardly between said tubes to said annular accumulator chamber;

(C) said coacting means in said tubes comprising

(1) a plurality of ports in said inner tube at longitudinally spaced locations along its side wall and defined generally along a straight line parallel to said axis, and

(2) a plurality of longitudinally spaced interior grooves in said outer tube respectively registering with said ports in said side wall of said inner tube and skewed with respect to the longitudinal axis of the shock absorber;

(D) said adjusting means comprising means providing relative rotation between said tubes to selectively vary the magnitude of the registration between the said ports and said grooves;

(E) said routing means comprising at least one longitudinal passage defined between said tubes, extending forwardly from a location adjacent the rearmost metering orifice to said accumulator chamber, intersecting each of said grooves as it extends forwardly to said accumulator chamber, being angularly displaced relative to said ports, and being defined in part by a longiudinally extending flat formed on the outer surface of said inner tube.

9. A shock absorber according to claim 8 wherein:

(F) said inner tube is flatted at diametrically opposed locations on its outer surface to provide two of said longitudinal passages.

10. A shock absorber according to claim 9 wherein:

(G) said straight line lies substantially angularly midway between said diametrically opposed flats.

11. In a shock absorber of the type including an inner tube closed at its rearward end and open at its forward end;

a piston rod and piston head assembly slidably received in the inner tube with the rearward end of the piston head spaced from the closed rearward end of the inner tube and the piston rod projecting forwardly out of the open forward end of the inner tube for impact by a moving object;

an outer tube surrounding the inner tube;

a cushioning fluid substantially filling the shock absorber;

means in the inner an outer tubes cooperating to define a plurality of metering orifices;

an adjusting means for providing relative movement between the tubes to selectively vary the size of the metering orifices and thereby selectively vary the impact resistance generated by the movement of the cushioning fluid through the metering orifices in response to impacting movement of the piston assembly toward the closed rearward end of the inner tube;

the improvement wherein;

(A) an annular acculumator chamber is provided in said shock absorber radially outwardly of said piston assembly at a longitudinal location forwardly of said metering orifices;

(B) means are provided for routing cushioning fluid from said orifices axially forwardly between said tubes to said annular accumulator chamber;

(C) said outer tube comprising the outer casing of said shock absorber and extends to a location forwardly of said inner tube; and

(D) said adjusting means comprises an adjuster member extending into the open forward end of said outer tube and engaging at its rearward end with the forward end of said inner tube and presenting an adjustment knob at its forward end positioned forwardly of the forward end of said outer tube.

12. A shock absorber according to claim 11 wherein:

(E) said adjustment member is annular;

(F) said adjutment knob is defined by the forward annular portion of said adjustment member; and

(G) said adjustment member further defines an annular bearing portion between its rearward end and said adjustment knob journalling said piston rod at its inner periphery and defining at its outer periphery the inner periphery of said annular accumulator chamber.

13. A shock absorber comprising:

(A) a piston assembly including a piston rod and a piston head;

(B) an inner tube

(1) having a closed rearward end and an open forward end,

(2) slidably receiving said piston assembly with the rearward end of said piston held spaced from said closed rearward end of said inner tube and said piston rod projecting forwardly out of said open forward end of said inner tube,

(3) having a plurality of longitudinally aligned ports formed at longitudinally spaced locations along its side wall, and

(4) having at least one longitudinally extending flat formed in its outer surface at a location angularly spaced from said ports;

(C) an outer tube

(1) comprising the outer casing of said shock absorber,

(2) surrounding said inner tube and mounting said inner tube for rotation therewithin,

(3) having a plurality of longitudinally spaced interior grooves respectively registering with said ports and said inner tube and skewed with respect to the longitudinal axis of said shock absorber, and

(4) extending to a location forwardly of the forward end of said inner tube; and

(D) an annular adjuster and bearing member

(1) received in the open forward end of said outer tube,

(2) having means at its rearward end engaging the forward end of said inner tube to rotate said inner tube in response to rotation of said adjuster and bearing member,

(3) defining an annular adjuster knob at its forward end positioned forwardly of the forward end of said outer tube, and

(4) defining an annular bearing portion between its rearward end and said adjuster knob journalling said piston rod at its inner periphery and coacting at its outer periphery with the confronting spaced inner periphery of said outer tube to define an annular accumulator chamber communicatng at its rearward end with the forward end of the longitudinal passage defined between said flat on said inner tube and the confronting inner surface of said outer tube.