US2175881A - Lubricating apparatus - Google Patents

Description

Oct. 10, 1939. E. w. DAVIS LUBRICATING APPARATUS A Filed Nov. ll, 1935 Patented Oct. 10, 1939 UNITED STATES PATENT OFFIQE LUBRICATING APPARATUS poration of Virginia Application November 11, 1935, Serial No. 49,174

2 Claims.

My invention relates generally to lubricating apparatus, and more particularly to oil cups adapted to be more or less permanently secured to the bearing to be lubricated, and constructed and arranged automatically to feed oil to the bearing.

Oil cups have been devised in which the oil is fed from a reservoir into a well containing air and forced from this well whenever the temperl ature of the bearing or the surrounding atmosphere increases. My invention relates to improvements in this type of oil cup, more particularly in the provision of improved means for preventing rapid draining of the reservoir of the l5 oil cup whenever the cap is removed from the reservoir during the operation of relling the latter.

It is thus an object of my invention to provide an improved oil cup construction in which means are provided to prevent rapid draining of the reservoir of the cup during the operation of lling the reservoir.

A further object is to provide an improved thermally controlled oil cup which is simple construction and may be economically manufactured.

Other objects will appear from the following description, reference being had to the accompanying drawing, in which 301 Fig. l is an elevation of my improved oil cup shown attached to a bearing to be lubricated, the latter being shown in transverse section; and

Fig. 2 is an enlarged central vertical sectional View taken on the line 2-2 of Fig. 1

The oil cup of my invention comprises a reser- Voir formed of a glass tube I0 which is clamped between a top I2 and bottom I4, suitable gaskets I6 and I8 being provided to seal the joints and to distribute the clamping pressure on the edges of the glass. A tube 20 is threaded on an upwardly extending boss 22 formed on the bottom I4y the upper end of the tube 2li being externally threaded to the top I2 so that the tube forms a tie rod between the top I2 and the bottom I4.

The tube has a plurality of apertures 24 through which the interior of the tube 20 is in communication with the reservoir I. The upper end of the tube 20 is normally closed by a cap 26 threaded over the end of the tube and which presses against an annular gasket 28 located in a suitable recess formed in the upper surface of the top I2. An opening 30 is provided in the tube 20 and is located so as to extend across the sealing surfaces of the gasket 28.

A Well 32 is threaded over an annular flange 34 formed integrally with the bottom I4 and has an annular gasket 36 located in a groove in its upper surface rThe gasket 36 forms an air-tight seal between the well and an annular ridge 38 projecting downwardly from the bottom I4 of the 5 reservoir. The well 32 is provided with a threaded shank 40 which is adapted to be screwed into the oil hole of a bearing, the shank being provided with a cylindrical bore 42 which communicates with the atmosphere through a vent po-rt 44 and l0 which communicates with the interior of the well S2 through an outlet port 46 of small diameter.

An outlet pipe 48 is secured in a boss 5B forming part of the bottom I4 and has its upper end communicating with an annular channel 52 15 formed in the upper surface of the bottom I4, the channel being covered by a ne mesh screen 54 which is held in place by the center tube 2D. rThe lower end of the outlet pipe 43 is restricted by a plug 55 which has a helical groove 58 formed 20 upon its external surface. The plug 5S is preferably secured in the lower end of the pipe 48 by a press t, although, if desired, it may be secured in place by other means.

An air escape tube 68 is secured in the boss 25 22 of the bottom I4 and at its upper end is restricted by a plug 62 which is similar to the plug 56 and has a helical groove 64 formed thereon. The lower end of the air tube B0 is preferably cut 01T at an angle as indicated at 66. The internal 30 diameters of the outlet pipe 48 and of the air escape tube 6U are so small that oil and air cannot simultaneously ow in opposite directions through either of these passageways.

In use the oil cup is screwed into the oil hole 35 68 of a bearing "I0, as indicated in Fig, 1, and assuming the reservoir to be lled or partially iilled with lubricant, the operation of the oil cup Will be as follows:

Oil will feed from the reservoir through the 40 iiltering screen 54, pipe 48, through the helical groove 58 and into the air trap or Well 32 until the level of the oil within the well 32 rises slightly above the lower end of the air tube 60. The outlet port 46 of the well 32 is of such small diameter 45 that oil and air will not simultaneously flow therethrough in o-pposite directionsl Since the reservoir and the well are sealed against atmospheric pressure, only a very minute quantity of oil will ilow from the opening 46 unless the tem- 50 perature of the air in the Well 32 is increased.

Whenever the bearing to which the oil cup is attached becomes slightly warm due to insufficient lubrication, heat will be transmitted from the bearing to the well 32, causing the air within 55 the well to expand and force oil from the well through the port 46 into the bearing. When this oil reaches the bearing the latter will gradually cool and as a result the air within the well 32 will again contract and form a partial vacuum within the well. This partial vacuum will result in drawing air from the atmosphere through the vent port 44 and outlet port 46. Whenever the level of the oil within the Well 32 drops below the end of the air trap pipe 60, some of the air will escape from the well 32 through the pipe 66 and will flow slowly around the helical groove 64 of the plug 62 into the tube 20 and thence through the apertures 24 into the reservoir l0, thus replacing the oil which is simultaneously owing therefrom through the pipe 48.

The air escape tube Ell will normally be iilled with air. The only time that it will be filled with oil is immediately after lling, Air entering the well 32 through the outlet port 46 will bubble upwardly directly into the tube 65 and replace the oil contained therein within a short time after the lubricator has been filled. Since the hydrostatic head upon the oil in the helical passageway 56 is greater than that upon the 011 in the upper end of the passageway 64, the oil will necessarily flow downwardly through the pipe 48 and passageway 58 while the air will ow upwardly through the air escape tube 66 and helical passageway 54. It will be understood that the air contained in the upper end of the reservoir I6 will, during normal operation of the device, be at sub-atmospheric pressure. The dii-ference between the pressure of the air in the upper end of the reservoir lll and that of the atmosphere will be substantially that represented by a column of oil extending from the outlet port 46 to the level of the oil in the reservoir l.

In oil cups of the above-described type which have been devised in the past, difficulty was eX- perienced in that whenever the cap 26 was removed for the purpose of relling the reservoir l0, such oil which remained in the reservoir would flow rather rapidly from the reservoir into the well and through the outlet port 46 into the bearing, flooding the latter and sometimes oW- ing also through the vent port 44 with resulting wastage of oil, and causing dripping of excess oil from the bearing. In some types of machinery the excess oil would soil and damage the product of the machine on which the bearing is mounted.

With the provision of the restriction plugs 56 and 62, the flow of oil from the reservoir into the bearing is hindered whenever the lling cap 26 is removed and the oil in the reservoir subjected to atmospheric pressure. If the restriction plugs 56 and 62 were not provided, all of the oil remaining in the reservoir would rapidly discharge through the outlet port 46, but since the grooves 58 and 64 in these plugs are of relatively small crosssectional area, the passage of oil from the reservoir to the well is hindered so that during the time that the filling cap 26 is removed only a very small excess quantity of lubricant will flow to the bearing. 'Ihe grooves in the plugs 56 and 62 are of sulicient size that they will not easily become clogged and are sufficiently long so as to oder appreciable resistance to the iiow of oil. Under the low hydraulic head which is present, the resistance plugs permit only very slow ow of oil from the reservoir.

While I have illustrated and described a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details set forth but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In an oil cup, the combination of a reservoir, an air trapping well associated therewith, a pair of pipes communicating with said reservoir and depending inte said well, and restriction plugs in said pipes, said plugs forming relatively long restricted permanently open passageways in said pipes to prevent rapid flow of oil from said reservoir to said well.

2. In an oil cup, the combination of a reser- Voir, an air trapping well associated therewith, an oil conducting passageway, and an air vent passageway, both of said passageways extending in a substantially Vertical direction and connecting said reservoir with said well, said air vent passageway having a restriction near its upper end and said oil conducting passageway having a restriction near its lower end, both of said restrictions forming continuously open channels for the ilow of fluid through said passageways.

ERNEST W. DAVIS.

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