Bearing lubricating device

Abstract

A bearing lubricating device .[.which.]. is designed for attachment to the wheel bearing housing of a trailer or other vehicle to automatically lubricate the bearings in the bearing housing. The bearing lubricating device includes a cylindrical grease housing fitted with a spring-loaded piston and a piston plate extending from the piston, wherein the piston projects from the end of the grease housing. When grease is charged into the interior of the grease housing, the spring is compressed and forces the piston farther outwardly of the grease housing, to indicate that sufficient grease is provided in the grease housing for proper lubrication of the wheel bearings. In a first preferred embodiment of the invention a stop ring is provided in the housing to limit travel of the piston plate and piston in the housing and the projecting end of the piston is color-coded to indicate the grease content inside the grease housing. In a second preferred embodiment a retainer is attached to the piston for the same purpose.

Having described my invention with the particularity set forth above, what is claimed is: 
     
       1. A bearing lubricating device for lubricating wheel bearings, comprising a generally cylindrically-shaped housing adapted to contain a lubricant, said housing having a closed end and an open end provided in communication with the wheel bearings; piston means slidably disposed in said housing, with one end of said piston means slidably projecting from said closed end of said housing; bias means provided in said housing, said bias means engaging said piston means for biasing said piston means inwardly of said housing and forcing the lubricant into contact with the wheel bearings; and a lubricant fitting seated in said housing for selectively introducing fresh lubricant into said housing. 
     
     
       2. The bearing lubricating device of claim 1 further comprising an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting. 
     
     
       3. The bearing lubricating device of claim 1 further comprising a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant. 
     
     
       4. The bearing lubricating device of claim 1 further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting; and   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant.   
     
     
       5. The bearing lubricant device of claim 1 further comprising a lubricant supply passage provided in said piston means and wherein said lubricant fitting is relocated in said piston means in communication with said lubricant supply passage. 
     
     
       6. The bearing lubricating device of claim 1 further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting;   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant; and   (c) a lubricant supply passage provided in said piston means and wherein said lubricant fitting is relocated in said piston means in communication with said grease supply passage.   
     
     
       7. The bearing lubricating device of claim 1 wherein said piston means further comprises a round piston plate slidably disposed in said housing between said closed end and said open end of said housing, and an elongated piston extending from said piston plate and having a piston end slidably extending through said closed end of said housing, and further comprising: (a) piston seal means provided in said closed end of said housing for sealing said piston in slidable relationship in said closed end of said housing; and   (b) piston plate seal means provided in the periphery of said piston plate for sealing said piston plate in slidable relationship in said housing.   
     
     
       8. The bearing lubricating device of claim 7 further comprising an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting. 
     
     
       9. The bearing lubricating device of claim 8 further comprising a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant. 
     
     
       10. The bearing lubricating device of claim 9 further comprising a lubricant supply passage longitudinally provided in said piston and said piston plate, said lubricant supply passage communicating with the lubricant in said housing, and wherein said lubricant fitting is relocated in said piston in communication with said lubricant supply passage. 
     
     
       11. The bearing lubricating device of claim 7 wherein said bias means further comprises a coil spring disposed in said housing between said piston plate and said closed end of said housing. 
     
     
       12. The bearing lubricating device of claim 11 further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting; and   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant.   
     
     
       13. The bearing lubricating device of claim 7 further comprising first and second color indicia provided on said piston end of said piston, for approximately indicating the quantity of lubricant in said housing responsive to slidable movement of said piston and said piston plate in said housing. 
     
     
       14. The bearing lubricating device of claim 13 further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting; and   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant.   
     
     
       15. The bearing lubricating device of claim 14 further comprising a lubricant supply passage longitudinally provided in said piston and said piston plate, said lubricant supply passage communicating with the lubricant in said housing and wherein said lubricant fitting is relocated in said piston in communication with said lubricant supply passage. 
     
     
       16. The bearing lubricating device of claim 15 wherein said bias means further comprises a coil spring disposed in said housing between said piston plate and said closed end of said housing. 
     
     
       17. The bearing lubricating device of claim 7 further comprising a stop ring groove provided in the inside wall of said housing in spaced relationship with respect to said closed end of said housing and a stop ring seated in said stop ring groove, for arresting the travel of said piston plate inwardly of said housing, responsive to the bias in said bias means. 
     
     
       18. The bearing lubricating device of claim 17 further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting; and   (b) a lubricant weep duct provided in said housing for lubricating when said housing is substantially filled with the lubricant.   
     
     
       19. The bearing lubricating device of claim 17 further comprising first and second color indicia provided on said piston end of said piston, for approximately indicating the quantity of lubricant in said housing, responsive to slidable movement of said piston and said piston plate in said housing. 
     
     
       20. The bearing lubricating device of claim 17 further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting;   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant; and   (c) first and second color indicia provided on said piston end of said piston, for approximately indicating the quantity of lubricant in said housing, responsive to slidable movement of said piston and said piston plate in said housing.   
     
     
       21. The bearing lubricating device of claim 17 further comprising a lubricant supply passage longitudinally provided in said piston and said piston plate, said lubricant supply passage communicating with the lubricant in said housing, and wherein said lubricant fitting is relocated in said piston in communication with said lubricant supply passage. 
     
     
       22. The bearing lubricating device of claim 17 wherein said bias means further comprises a coil spring disposed in said housing between said piston plate and said closed end of said housing and further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting;   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant;   (c) first and second color indicia provided on said piston end of said piston, for approximately indicating the quantity of lubricant in said housing; and   (d) a lubricant supply passage longitudinally provided in said piston and said piston plate, said lubricant supply passage communicating with the lubricant in said housing, and wherein said lubricant fitting is relocated in said piston in communication with said lubricant supply passage.   
     
     
       23. The bearing lubricating device of claim 7 further comprising retainer means disposed on said piston end, whereby said piston end is prevented from recessing in said opposite end of said housing responsive to the bias of said bias means when the quantity of lubricant is reduced in said housing. 
     
     
       24. The bearing lubricating device of claim 23 further comprising an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting. 
     
     
       25. The bearing lubricating device of claim 23 further comprising a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant. 
     
     
       26. The bearing lubricating device of claim 23 wherein said bias means further comprises a coil spring disposed in said housing between said piston plate and said opposite end of said housing. 
     
     
       27. The bearing lubricating device of claim 23 wherein said bias means further comprises a coil spring disposed in said housing between said piston plate and said opposite end of said housing and further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting; and   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant.   
     
     
       28. The bearing lubricating device of claim 27 wherein said retainer means further comprises a flange and a plurality of flange tabs provided in said flange for engaging said piston, said flange adapted to engage said opposite end of said housing and arrest the travel of said piston plate inwardly of said housing responsive to the bias in said coil spring. 
     
     
       29. The bearing lubricating device of claim 28 further comprising first color indicia provided on said flange and said piston end of said piston and second color indicia provided on said piston adjacent to said first color indicia, for approximately indicating the quantity of lubricant in said housing, responsive to slidable movement of said piston and said piston plate in said housing. 
     
     
       30. A bearing lubricating device for mounting in a wheel housing and lubricating wheel bearings provided in the wheel housing, said bearing lubricating device comprising a generally cylindrically-shaped housing adapted to contain a lubricant and having a closed end and an open end spaced from said closed end, said open end provided in communication with the wheel bearings; a stop ring groove provided in the inside wall of said housing in spaced relationship with respect to said closed end of said housing and a stop ring seated in said stop ring groove; a round piston plate slidably disposed in said housing between said stop ring and said closed end of said housing and piston plate seal means provided in the periphery of said piston plate for sealing said piston plate in slidable relationship in said housing; a piston access opening provided in said closed end of said housing and piston seal means provided in said piston access opening; a piston extending from said piston plate through said piston access opening and said seal means, wherein said piston is sealed in slidable relationship in said piston access opening by said piston seal means; a coil spring located in said housing between said piston plate and said closed end of said housing for biasing said piston plate toward said open end of said housing; and a lubricant fitting seated in said housing for selectively introducing fresh lubricant into said housing, whereby said piston plate exerts pressure on lubricant provided in said housing between said piston plate and said open and .[.and.]. causes the lubricant to coat the wheel bearings, responsive to the bias of said coil spring. 
     
     
       31. The bearing lubricating device of claim 30 further comprising an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting. 
     
     
       32. The bearing lubricating device of claim 30 further comprising a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant. 
     
     
       33. The bearing lubricating device of claim 30 further comprising a lubricant supply passage provided in said piston and said piston plate, said lubricant supply passage communicating with the lubricant in said housing, and wherein said lubricant fitting is relocated in the extending end of said piston, said lubricant fitting provided in communication with said lubricant supply passage, for selectively introducing lubricant into said housing. 
     
     
       34. The bearing lubricating device of claim 30 further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting; and   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant.   
     
     
       35. The bearing lubricating device of claim 34 further comprising a lubricant supply passage provided in said piston and said piston plate, said lubricant supply passage communicating with the lubricant in said housing, and wherein said lubricant fitting is relocated in the extending end of said piston, said lubricant fitting provided in communication with said lubricant supply passage, for selectively introducing lubricant into said housing. 
     
     
       36. The bearing lubricating device of claim 30 further comprising first and second color indicia provided on the extending end of said piston, for approximately indicating the quantity of lubricant in said housing, responsive to slidable movement of said piston and said piston plate in said housing. 
     
     
       37. The bearing lubricating device of claim 30 further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting;   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant; and   (c) first and second color indicia provided on the extending end of said piston, for approximately indicating the quantity of lubricant in said housing, responsive to slidable movement of said piston and said piston plate in said housing.   
     
     
       38. The bearing lubricating device of claim 37 further comprising a lubricant supply passage provided in said piston and said piston plate, said lubricant supply passage communicating with the lubricant in said housing, and wherein said lubricant fitting is relocated in the extending end of said piston in communication with said lubricant supply passage. 
     
     
       39. A bearing lubricating device for mounting in a wheel housing and lubricating wheel bearings provided in the wheel housing, said bearing lubricating device comprising a generally cylindrically-shaped housing adapted to contain a lubricant and having a closed end and an open end spaced from said closed end, said open end provided in communication with the wheel bearings; a round piston plate slidably disposed in said housing between said open end and said closed end of said housing and piston plate seal means provided in the periphery of said piston plate for sealing said piston plate in slidable relationship in said housing; a piston access opening provided in said closed end of said housing and piston seal means provided in said piston access opening; a piston extending from said piston plate through said piston access opening and said seal means, wherein said piston is sealed in slidable relationship in said piston access opening by said piston seal means; retainer means disposed on the end of said piston extending through said piston access opening for retaining a portion of the extending end of said piston outside of said housing when the quantity of lubricant is reduced in said housing; a lubricant fitting seated in said housing for selectively introducing fresh lubricant into said housing; and a coil spring located in said housing between said piston plate and said closed end of said housing for biasing said piston plate toward said open end of said housing, whereby said piston plate exerts pressure on the lubricant provided in said housing and causes the lubricant to coat the wheel bearings, responsive to the bias of said coil spring. 
     
     
       40. The bearing lubricating device of claim 39 further comprising an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting. 
     
     
       41. The bearing lubricating device of claim 39 further comprising a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant. 
     
     
       42. The bearing lubricating device of claim 39 further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting; and   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant.   
     
     
       43. The bearing lubricating device of claim 39 further comprising a lubricant supply passage provided in said piston and said piston plate, said lubricant supply passage communicating with the lubricant in said housing, and wherein said lubricant fitting is relocated in said extending end of said piston, said lubricant fitting provided in communication with said lubricant supply passage, for selectively introducing lubricant into said housing. 
     
     
       44. The bearing lubricating device of claim 39 wherein said retainer means further comprises a flange and a plurality of flange tabs provided in said flange for engaging said piston, said flange adapted to engage said closed end of said housing and arrest the travel of said piston plate inwardly of said housing, responsive to the bias in said coil spring. 
     
     
       45. The bearing lubricating device of claim 44 further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting; and   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant.   
     
     
       46. The bearing lubricating device of claim 44 further comprising a lubricant supply passage provided in said piston and said piston plate, said lubricant supply passage communicating with the lubricant in said housing, and wherein said lubricant fitting is relocated in said extending end of said piston, said lubricant fitting provided in communication with said lubricant supply passage, for selectively introducing lubricant into said housing. 
     
     
       47. The bearing lubricating device of claim 39 further comprising first color indicia provided on said flange and said extending end of said piston and second color indicia provided on said extending end of said piston adjacent to said first color indicia, for approximately indicating the quantity of lubricant in said housing, responsive to slidable movement of said piston and said piston plate in said housing. 
     
     
       48. The bearing lubricating device of claim 44 further comprising: (a) an air escape duct provided in said housing for allowing air to escape from said housing when the lubricant is introduced into said housing through said lubricant fitting; and   (b) a lubricant weep duct provided in said housing for indicating when said housing is substantially filled with the lubricant.   
     
     
       49. The bearing lubricating device of claim 48 further comprising a lubricant supply passage provided in said piston and said piston plate, said lubricant supply passage communicating with the lubricant in said housing, and wherein said lubricant fitting is relocated in said extending end of said piston, said lubricant fitting provided in communication with said lubricant supply passage, for selectively introducing lubricant into said housing. .Iadd.50. A bearing lubricating device for lubricating a bearing, said bearing lubricating device comprising: a housing having a first end and a second end, said housing having a housing chamber therein, said housing chamber having a first end and a second end;   a piston slidably disposed in said housing chamber, said housing chamber being divided by said piston into a first chamber and a second chamber, said first chamber being adapted to contain a lubricant, said housing providing for communication between said first chamber and the bearing, said piston having one end portion slidably projecting through said second end of said housing chamber and said second end of said housing to an outer end of said one end portion;   a bias element provided in said housing, said bias element engaging said piston for biasing said piston towards said first end of said housing chamber and thereby forcing lubricant from said first chamber towards the bearing; and   a lubricant fitting for selectively introducing fresh lubricant into said first chamber;   wherein said one end portion is colored to provide an external visual indication of whether the quantity of lubricant in said first chamber is   
     
     
        sufficient to lubricate the bearing. .Iaddend. .Iadd.51.  A bearing lubricating device in accordance with claim 50 wherein said one end portion of said piston contains a lubricant supply passage in communication with said first chamber, and wherein said lubricant fitting is positioned on said outer end of said one end portion exteriorly of said housing and in communication with said lubricant supply passage. .Iaddend. .Iadd.52. A bearing lubricating device in accordance with claim 50 wherein said one end portion has at least first and second color areas of differing colors, said second color area being located between said first color area and the outer end of said one end portion of the piston. .Iaddend. .Iadd.53. A bearing lubricating device in accordance with claim 50 further comprising an air escape duct provided in said housing for allowing air to escape from said second chamber when lubricant is introduced into said first chamber through said lubricant fitting. .Iaddend. .Iadd.54. A bearing lubricating device in accordance with claim 50 wherein said piston comprises a piston plate slidably disposed in said housing chamber to divide said housing chamber into said first chamber and said second chamber, wherein said one end portion is an elongated portion having a smaller diameter than said piston plate and connected to and extending from said piston plate to said outer end. .Iaddend. .Iadd.55. A bearing lubricating device in accordance with claim 54 wherein said piston further comprises a piston seal provided in the periphery of said piston plate for sealing said piston plate in slidable relationship in said housing chamber. .Iaddend. .Iadd.56. A bearing lubricating device in accordance with claim 50 wherein said second end of said housing has a piston access opening provided therein through which said one end portion extends so as to at least substantially close said second end of said housing. .Iaddend. .Iadd.57. A bearing lubricating device in accordance with claim 56 wherein said second end of said housing further comprises a piston seal provided in the periphery of said piston access opening for sealing said one end portion in slidable relationship in said second end of said housing. .Iaddend. .Iadd.58. A bearing lubricating device in accordance with claim 50 wherein said first end of said housing is open to provide communication of said first chamber with said bearing. .Iaddend. .Iadd.59. A bearing lubricating device in accordance with claim 50 wherein said one end portion of said piston comprises a retainer positioned externally of said housing to prevent said one end portion from completely recessing in said second end of said housing responsive to the bias of said bias element when the quantity of lubricant in said first chamber has reached a sufficiently low level to require recharging of lubricant into said first chamber. .Iaddend. .Iadd.60. A bearing lubricating device in accordance with claim 50 wherein a first color area is positioned on said one end portion such that at least a portion of said first color area extends outside said housing when said first chamber contains sufficient lubricant and said first color area is retracted inside the housing when additional lubricant should be charged into said first chamber. .Iaddend. .Iadd.61. A bearing lubricating device in accordance with claim 60 wherein said one end portion of said piston contains a longitudinally extending lubricant supply passage in communication with said first chamber, and wherein said lubricant fitting is positioned on said outer end of said one end portion exteriorly of said housing and in communication with said lubricant supply passage. .Iaddend. .Iadd.62. A bearing lubricating device in accordance with claim 61 wherein said one end portion of said piston comprises a retainer positioned externally of said housing to limit the travel of said one end portion inwardly of said housing responsive to the bias of said bias element and to indicate when the quantity of lubricant in said first chamber has reached a sufficiently low level to require recharging of lubricant into said first chamber. .Iaddend. .Iadd.63. A bearing lubricating device in accordance with claim 61 wherein said piston comprises a piston plate slidably disposed in said housing chamber to divide said housing chamber into said first chamber and said second chamber, wherein said one end portion is an elongated portion having a smaller diameter than said piston plate and connected to and extending from said piston plate to said outer end. .Iaddend. .Iadd.64. A bearing lubricating device in accordance with claim 63 wherein said piston further comprises a piston seal provided in the periphery of said piston plate for sealing said piston plate in slidable relationship in said housing chamber. .Iaddend. .Iadd.65. A bearing lubricating device in accordance with claim 64 wherein said second end of said housing has a piston access opening provided therein through which said one end portion extends so as to at least substantially close said second end of said housing. .Iaddend. .Iadd.66. A bearing lubricating device in accordance with claim 65 wherein said second end of said housing further comprises a piston seal provided in the periphery of said piston access opening for sealing said one end portion in slidable relationship in said second end of said housing. .Iaddend. .Iadd.67. A bearing lubricating device in accordance with claim 66 further comprising an air escape duct provided in said housing for allowing air to escape from said second chamber when lubricant is introduced into said first chamber through said lubricant fitting. .Iaddend. .Iadd.68. A bearing lubricating device in accordance with claim 67 wherein said first end of said housing is open to provide communication 
     
     
        of said first chamber with said bearing. .Iaddend. .Iadd.69.  A bearing lubricating device for lubricating a wheel bearing located in a wheel bearing housing, said bearing lubricating device comprising: a device housing having a first end and a second end, said first end of said device housing being adapted to be removably secured to the wheel bearing housing, said device housing having a housing chamber therein, said housing chamber having a first end and a second end;   a piston slidably disposed in said housing chamber, said housing chamber being divided by said piston into a first chamber and a second chamber, said first chamber being adapted to contain a lubricant, said device housing providing for communication between said first chamber and the bearing through said first end of said device housing, said piston having one end portion slidably projecting through said second end of said housing chamber and extending outwardly through said second end of said device housing to an outer end of said one end portion;   a bias element provided in said device housing, said bias element engaging said piston for biasing said piston towards said first end of said housing chamber and thereby forcing lubricant from said first chamber towards the bearing; and   a lubricant fitting for selectively introducing fresh lubricant into said first chamber;   wherein said one end portion is color-coded to provide an external visual indication of the quantity of lubricant in said first chamber. .Iaddend. .Iadd.70. A bearing lubricating device in accordance with claim 69 wherein said one end portion of said piston contains a lubricant supply passage in communication with said first chamber, and wherein said lubricant fitting is positioned on said outer end of said one end portion exteriorly of said device housing and in communication with said lubricant supply passage. .Iaddend. .Iadd.71. A bearing lubricating device in accordance with claim 69 wherein said one end portion has at least first and second color areas of differing colors, said second color area being located between said first color area and the outer end of said one end portion of the piston. .Iaddend. .Iadd.72. A bearing lubricating device in accordance with claim 69 further comprising an air escape duct provided in said device housing for allowing air to escape from said second chamber when the lubricant is introduced into said first chamber through said lubricant fitting. .Iaddend. .Iadd.73. A bearing lubricating device in accordance with claim 69 wherein said piston comprises a piston plate slidably disposed in said housing chamber to divide said housing chamber into said first chamber and said second chamber, wherein said one end portion is an elongated portion having a smaller diameter than said piston plate and connected to and extending from said piston plate to said outer end. .Iaddend. .Iadd.74. A bearing lubricating device in accordance with claim 73 wherein said piston further comprises a piston seal provided in the periphery of said piston plate for sealing said piston plate in slidable relationship in said housing chamber. .Iadd.75. A bearing lubricating device in accordance with claim 69 wherein said second end of said device housing has a piston access opening provided therein through which said one end portion extends so as to at least substantially close said second end of said device housing. .Iaddend. .Iadd.76. A bearing lubricating device in accordance with claim 75 wherein said second end of said device housing further comprises a piston seal provided in the periphery of said piston access opening for sealing said one end portion in slidable relationship in said second end of said device housing. .Iaddend. .Iadd.77. A bearing lubricating device in accordance with claim 69 wherein said first end of said device housing is open to provide communication of said first chamber with said bearing. .Iaddend. .Iadd.78. A bearing lubricating device in accordance with claim 69 wherein said one end portion of said piston comprises a retainer positioned externally of said device housing to prevent said one end portion from completely recessing in said second end of said device housing responsive to the bias of said bias element when the quantity of lubricant in said first chamber has reached a sufficiently low level to require recharging of lubricant into said first chamber. .Iaddend. .Iadd.79. A bearing lubricating device in accordance with claim 71 wherein said first color area is positioned on said one end portion such that at least a portion of said first color area extends outside said device housing when said first chamber contains sufficient lubricant and said first color area is retracted inside the device housing when additional lubricant should be charged into said first chamber. .Iaddend. .Iadd.80. A bearing lubricating device in accordance with claim 79 wherein said one end portion of said piston contains a longitudinally extending lubricant supply passage in communication with said first chamber, and wherein said lubricant fitting is positioned on said outer end of said one end portion exteriorly of said device housing and in communication with said lubricant supply passage. .Iaddend. .Iadd.81. A bearing lubricating device in accordance with claim 79 wherein said one end portion of said piston comprises a retainer positioned externally of said device housing to limit the travel of said one end portion inwardly of said device housing responsive to the bias of said bias element and to indicate when the quantity of lubricant in said first chamber has reached a sufficiently low level to require recharging of lubricant into said first chamber. .Iaddend. .Iadd.82. A bearing lubricating device in accordance with claim 79 wherein said piston comprises a piston plate slidably disposed in said housing chamber to divide said housing chamber into said first chamber and said second chamber, wherein said one end portion is an elongated portion having a smaller diameter than said piston plate and connected to and extending from said piston plate to said outer end. .Iaddend. .Iadd.83. A bearing lubricating device in accordance with claim 82 wherein said piston further comprises a piston seal provided in the periphery of said piston plate for sealing said piston plate in slidable relationship in said housing chamber. .Iaddend. .Iadd.84. A bearing lubricating device in accordance with claim 79 wherein said second end of said device housing has a piston access opening provided therein through which said one end portion extends so as to at least substantially close said second end of said device housing. .Iaddend. .Iadd.85. A bearing lubricating device in accordance with claim 84 wherein said second end of said device housing further comprises a piston seal provided in the periphery of said piston access opening for sealing said one end portion in slidable relationship in said second end of said device housing. .Iaddend. .Iadd.86. A bearing lubricating device in accordance with claim 79 further comprising an air escape duct provided in said device housing for allowing air to escape from said second chamber when lubricant is introduced into said first chamber through said lubricant fitting. .Iaddend. .Iadd.87. A bearing lubricating device in accordance with claim 79 wherein said first end of said device housing is open to provide communication of said first chamber with said bearing. .Iaddend.