Hydraulic--pneumatic cushioning device with pressure indicator

• US 5,351,562 A
• Filed: 12/15/1993
• Issued: 10/04/1994
• Est. Priority Date: 01/24/1992
• Status: Expired due to Term

• Current Assignee: Amsted Rail Company Incorporated (Amsted Industries Incorporated)
• Original Assignee: Keystone Railway Equipment Company, Inc.
• Inventors: Scott, Mark P.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): ROSKOS, JOSEPH
• Application Number:
  US08/167,454
• Time in Patent Office: 293 Days
• Field of Search: 116/272, 116/205, 116/279, 116/DIG. 28, 73/37, 73/47, 73/39, 73/11
• US Class Current: 73/37
• CPC Class Codes: F16F 9/0209 Telescopic F16F9/04 takes precedence
• CPC Class Codes: F16F 9/3264 Arrangements for indicating, e.g. fluid level; Arrangements for checking dampers F16F9/3292 takes precedence; testing of vehicle damping G01M17/04
• CPC Class Codes: G01M 17/04 Suspension or damping

Abstract

A hydraulic-pneumatic cushioning device including a pressure indicator mounted on the device or remote from the device and connected to the pressure chamber within the cushioning device. The indicator includes a recess and a small pin extending into the recess. The position of the pin relative to the recess provides a tactile indication of the condition of the cushioning device.

Claims

1. A hydraulic-pneumatic cushioning device for cushioning railway cars, said device comprising a body, a piston guide within the body, a piston fitted in the guide, a piston rod connected to the piston and extending outwardly of the body, a fluid reservoir within the body, a fluid in the reservoir including hydraulic fluid and pressurized gas, and a pressure indicator connected to said body and located in communication with fluid in the reservoir, said pressure indicator including pressure sensing means for sensing the pressure of the fluid in the reservoir;

movable tactile indicator means for indicating, by touch of the tactile indicator means, the pressure of the fluid in the reservoir, said tactile indicator means being exposed on the outside of the body, connected to the pressure sensing means and adapted to be moved outwardly of the body to an extended position;

said pressure sensing means including piston means disposed within said pressure indicator for moving tactile indicator means from a retracted position inside said pressure indicator to an extended position outside said pressure indicator;

biasing means disposed entirely within said pressure indicator for urging said piston means and tactile indicator means to move the tactile indicator means from the extended position toward the retracted position;

seal means for precluding fluid from exiting said pressure indicator, said seal means being disposed about said piston means and positioned between said biasing means and said tactile indicator means; and

means for communicating hydraulic fluid from said reservoir to said pressure sensing means and said seal means in said pressure indicator.

2. A device as in claim 1 wherein the pressure indicator includes a head, a bore extending into an exterior surface on the head, and said tactile indicator means comprises a pin slidably fitted within the bore and having a free end located adjacent the exterior surface on the head, said free end being located outwardly of the exterior surface on the head when in the extended position and being located essentially flush with the exterior surface on the head when in the retracted position.

3. A device as in claim 2 including a recess formed in the surface of the head, said bore being located within the recess.

4. A device as in claim 2 wherein the pin is directly connected to the piston means.

5. A device as in claim 2 wherein said seal means is mounted in the head, the seal means surrounding the pin and the bore, and said device including a passage communicating the reservoir and the seal means.

6. A device as in claim 5 wherein the seal means is located below the level of hydraulic fluid within the reservoir.

7. A device as in claim 6 wherein the seal means includes a circumferential pressure seal surrounding the pin.

8. A device as in claim 7 wherein the seal means includes an annular base facing the recess and an annular flexible seal ring mounted on the base and facing away from the recess.

9. A device as in claim 6 including a threaded connection joining the pressure indicator to the cushioning device body, a circumferential step surrounding the exterior of the pressure indicator and facing the cushioning device body, and a circumferential seal member extending around the outside of the pressure indicator and engaging the step and the cushioning device body at the step to form a pressure seal between the pressure indicator and the cushioning device.

10. A device as in claim 9 wherein the step is located between the threaded connection and said head.

11. A device as in claim 4 wherein said piston means comprises a piston and said biasing means comprises a helical spring surrounding at least a portion of the piston.

12. A device as in claim 11 including a spring retention washer mounted in said head further away from said recess than said seal means, said pin extending through the spring retention means and including a head on the piston away from the pin, said spring being confined between the spring retention means and said head on the piston.

13. A device as in claim 2 wherein said head is directly mounted on the cushioning device body.

14. A device as in claim 2 wherein said head is located remotely from the cushioning device body and including a hydraulic line having ends joined to the head and the body and forming a fluid connection between the fluid reservoir within the body and the head.

15. A device as in claim 3 including a removable cap mounted on said head overlying the recess and pin.

16. The combination of a railway car having a load supporting surface and opposed sides and ends, and a hydraulic-pneumatic cushioning device as in claim 4 secured to one end of the railway car with the piston rod extending outwardly of the car for coupling with another railway car.

17. The combination of claim 16 wherein the pressure indicator is mounted directly on the body of the cushioning device.

18. The combination of claim 16 wherein the exposed tactile indicator means is located on the side or end of the railway car.

19. The combination of claim 18 wherein the pressure sensing means is located adjacent the exposed tactile indicator means and including a pressure line joining the reservoir within the cushioning device body and the pressure sensing means.

20. A device as in claim 1 wherein said piston means includes a piston and a piston passage for receipt of fluid communicated from said reservoir.

21. A device as in claim 20 wherein said cushioning device includes a fluid passage for communicating fluid from said reservoir to said piston passage.

22. A pressure indicator for a hydraulic-pneumatic cushioning device having hydraulic fluid under pressure therein, said indicator comprising an elongated generally cylindrical body defining an open ended interior passage extending along the length of the body, a slide member fitted within the interior passage and movable back and forth along the passage to extend an end of the slide member outwardly of one end of the passage and retract the end back into the passage, a seal fitted within the passage adjacent the one end thereof, the seal surrounding the slide member for preventing hydraulic fluid from flowing out the one end of the passage, a spring disposed entirely within said passage and biasing the slide member away from the one end of the passage, and fastening means disposed on the exterior of the body, the slide member including a piston disposed within the passage and located at the other end of the passage, and a pin at said one end of the passage, said pin being smaller in diameter than said piston and extending through the seal;

passage means for permitting hydraulic fluid under pressure from a cushioning device to travel to said one end of said passage and communicate with and lubricate said seal and pin; and

retaining means located in said passage between said second opening and said slide member for limiting the travel of said slide member toward said second passage opening.

23. A pressure indicator as in claim 22 including a recess in the exterior surface of the body at said one end of the passage whereby movement of the slide member in the passage moves the end of the pin between a position within the recess and a position flush with the surface of the bottom at the recess.

24. A pressure indicator as in claim 22 wherein said spring is positioned within the passage and surrounds the slide member.

25. A pressure indicator as in claim 22 including a fluid path communicating the other end of the passage with the seal.

26. A pressure indicator as in claim 22 including a snap ring fitted within the other end of the passage wherein the spring biases the slide member against the snap ring.

27. A pressure indicator as in claim 22 including circumferential threads formed on the exterior of the body and a bleed passage formed through the wall of the cylindrical body between the threads and the seal.

28. A pressure indicator in accordance with claim 22 wherein said fastening means includes threads formed on the exterior of said pressure indicator body.

29. A pressure indicator in accordance with claim 22 wherein said piston includes a piston passage for the receipt of fluid located in a cushioning device reservoir.

56. A pressure indicator in accordance with claims 22, 34 or 52 including threads formed on the exterior of said pressure indicator body, a circumferential step extending around the exterior of said body, and circumferential seal means extending around said body between the threads and the step for forming a seal between the pressure indicator and a cushioning device.

30. The method of determining the fluid pressure in a hydraulic-pneumatic cushioning device which comprises a body, a piston guide within the body, a piston fitted in the guide, a piston rod connected to the piston and extending outwardly of the body, a fluid reservoir within the body, a fluid in the reservoir including hydraulic fluid and pressurized gas, and a pressure indicator connected to said body and located below at least a portion of the reservoir, said pressure indicator including a body, pressure sensing means disposed within said body for sensing the pressure of the fluid in the reservoir, exposed movable tactile indicator means adapted to extend outside said body, said tactile indicator means connected to the pressure sensing means for indicating, by touch of the tactile indicator means, the pressure generated by fluid in the reservoir;

and,

said pressure indicator including a piston rod means connected to said pressure sensing means and disposed within said indicator for actuating said movable tactile indicator to move said indicator to a position outside of said indicator;

seal means for precluding fluid from exiting said pressure indicator device, said seal means being disposed about said piston rod and positioned between said pressure sensing means and said tactile indicator means; and

,

means for communicating fluid from said reservoir within said body to said seal means in said pressure indicator;

said method comprising the steps of;

a) moving the position of said exposed tactile indicator means located outside the device in response to the fluid pressure within the reservoir;

b) tactilly feeling the tactile indicator means to sense the position of the indicator means to determine the pressure in the reservoir;

c) communicating fluid from said cushioning device reservoir to said pressure indicator (i) to act upon said pressure sensing means to cause said tactile indicator to move to said position outside said indicator; and

(ii) to contact said seal means in said pressure indicator; and

d) sealing said fluid from exiting said pressure indicator at the location of said tactile means while lubricating said piston rod at the location of said tactile indicator means.

31. The method of claim 30 including the steps of moving the indicator means outwardly of a surface to indicate high pressure within the reservoir, and moving the indicator means inwardly toward the surface to indicate low pressure within the reservoir.

32. The method of claim 31 wherein said surface is located in the bottom of a recess and including the step of moving the indicator to the edge of the recess to indicate high pressure within the reservoir.

33. The method of claim 32 including the step of pushing the indicator means from the position outwardly of the surface of the indicator body toward said surface, releasing the indicator means, and pressure-returning the indicator means to the high pressure position when the pressure of the fluid in a reservoir means is greater than a minimum operating pressure.

34. A pressure indicator for use with a cushioning device having fluid under pressure therein, said indicator being adapted to provide a tactile indication of the fluid pressure in the cushioning device, said indicator comprising:

an elongated cylindrical body having an internal passage extending along the length of said body and a first opening located at one end of said passage and a second opening located at another end of said passage;

a movable slide member having a first end and a second end, said slide member being disposed within and movable along the length of said passage;

said first end of said slide member being adapted to extend through and beyond said first opening;

said second end of said slide member being disposed entirely within said passage and normally positioned contiguous to said second opening to be contacted by fluid from said cushioning device, said fluid pressure being adapted to urge a portion of said slide member through said first opening;

biasing means disposed entirely within said indicator and contacting said slide member for urging said slide member toward said second opening;

fluid seal means in said passage and surrounding said slide member for sealing fluid from exiting said first opening, said seal means being disposed contiguous to said first opening between said biasing means and said first opening;

means for retaining said slide member and said biasing means from exiting said second opening, said retaining means being located in said passage between said second opening and said slide member; and

,

passage means for permitting fluid under pressure to travel from said second opening and communicate with said seal means.

35. A pressure indicator in accordance with claim 34 and further including fastening means disposed externally on said body for fastening said indicator to a cushioning device.

36. A pressure indicator in accordance with claim 35 wherein said fastening means comprises threads on an exterior surface of said body.

37. A pressure indicator in accordance with claim 34 wherein said body has a recess in said exterior surface adjacent said first opening whereby said slide member is adapted to project into said recess.

38. A pressure indicator in accordance with claim 34 wherein said passage means extends between said body and said slide member for allowing fluid from a cushioning device to enter said passage at said second opening and travel along the passage to said seal means.

39. A pressure indicator in accordance with claim 38 wherein said slide member includes a piston portion located at said second end.

40. A pressure indicator in accordance with claim 39 wherein said first end of said slide member includes a pin extending out from said piston portion and having a free end which is adapted to extend out of said first opening.

41. A pressure indicator in accordance with claim 38 wherein said passage means includes a fluid passage which extends through at least a portion of said slide member.

42. A pressure indicator in accordance with claim 37 wherein said retaining means comprises a snap ring disposed in said body contiguous to said second opening.

43. A pressure indicator in accordance with claim 42 wherein said snap ring is engageable with said slide member.

44. A pressure indicator device in accordance with claim 34 wherein said body includes a first abutment means disposed along the length of said passage for limiting the travel of said biasing means along the length of said passage.

45. A pressure indicator in accordance with claim 44 wherein said first abutment means is annular shaped.

46. A pressure indicator in accordance with claim 45 and further including a spring retention means seated against said first abutment means and contacting said biasing means.

47. A pressure indicator in accordance with claim 46 and further including a retainer means disposed within said passage, surrounding said slide member and engageable with said first abutment means and said biasing means for maintaining said biasing means in position in said passage.

48. A pressure indicator in accordance with claim 44 wherein said seal means is positioned between said first abutment means and said first opening.

49. A pressure indicator in accordance with claim 44 wherein said biasing means comprises a helical spring.

50. A pressure indicator in accordance with claim 47 and further including a second abutment means disposed along the length of said passage and spaced from said first abutment means for serving as an abutment for said seal means.

51. A pressure indicator in accordance with claim 34 wherein said seal means is fluid pressure activated.

55. A pressure indicator in accordance with claim 34 or 52 in combination with a cushioning device which comprises a body, a chamber within said body, a piston within said chamber, a piston rod connected to said piston, said rod extending outside of said body, a fluid reservoir within said body and fluid under pressure disposed within said reservoir, and means connecting said fluid reservoir with said pressure indicator for permitting fluid from said reservoir in said cushioning device to enter said pressure indicator and contact said slide member for urging said one end of said slide member through said first passage opening.

52. A pressure indicator for a hydraulic-pneumatic cushioning device used in railway cars and having fluid under pressure located in a reservoir in said cushioning device, said pressure indicator comprising an elongated generally cylindrical body defining an open ended interior passage extending along the length of the indicator body;

a first opening at one end of the passage and a second opening at the other end of the passage, a slide member having two ends fitted entirely within the interior passage, the slide member being movable back and forth along the passage and adapted to have one end of the slide member extend outwardly of the first passage opening and retract back into the passage;

seal means fitted within the passage contiguous to the first passage opening, the seal means surrounding the slide member for preventing fluid from flowing out the passage, a spring disposed entirely within the indicator body for biasing the slide member away from the first passage opening;

retention means located at the opposite end of the slide member for retaining the slide member within the indicator, said retention means being located between said second opening and said slide member;

fastening means located on the exterior of the indicator body for fastening said indicator to a cushioning device;

said slide member including a piston and a pin including tactile indicator means located at the free end of the pin, said pin extending through the seal means;

said seal means being positioned between said spring and said first opening in said passage; and

passage means for permitting fluid under pressure to travel from said second opening and communicate with said seal means located contiguous to said first opening.

53. A pressure indicator in accordance with claim 52 wherein a portion of the exterior of said elongate body is hexagonally shaped for receipt of a fastening tool.

54. A pressure indicator in accordance with claim 53 wherein said fastening means comprises threads located on the exterior surface of said body.