US3254740A

US3254740A - Lubricating device for sewing machines

Info

Publication number: US3254740A
Application number: US318738A
Authority: US
Inventors: Bono Luigi
Original assignee: Necchi SpA
Current assignee: Necchi SpA
Priority date: 1962-10-25
Filing date: 1963-10-24
Publication date: 1966-06-07
Anticipated expiration: 1983-06-07
Also published as: GB991955A; BE638708A; DE1485251A1

Description

June 7, 1966 L. BONO LUBRICATING DEVICE FOR SEWING MACHINES Filed Oct. 24, 1963 5 Sheets-Sheet 1 INVEM OR lz/zyz 50770 ATTORNEYS June 7, 1966 L. BONO 3,254,740

LUBRICATING DEVICE FOR SEWING MACHINES Filed Oct. 24, 1963 v 5 Sheets-Sheet 2 INVENT OR Zz/z'yz' 50220 ATTORNEYS June 7, 1966 BONO 3,

LUBRICATING DEVICE FOR SEWING MACHINES Filed Oct. 24, 1963 5 Sheets-$heet 5 izggz' 30220 ATTORNEYS return to the reservoir.

United States Patent 7 Claims. (Cl. 184-6) This invention relates to a lubricating device with oil recovery for sewing machines running at high speed. The device comprises a reservoir for the oil, means capable of distributing the oil from the reservoir to the mechanical parts of the machine to be lubricated, an oil sump for gathering the oil, and a suction pump capable of moving the oil from the sump to the reservoir. The invention is characterized mainly by the fact that the suction pump comprises a bushing placed in the reservoir over the oil level and wherein said bushing embraces a shaft of the sewing machine at which point commence .two opposite spiral notches. The bushing is provided with two holes extending substantially radially. Into each of said holes is inserted one end of a duct. The other end of one of these ducts communicates with the oil sump, whereas the other end of the second duct communicates directly with the reservoir so that the pump is easily primed.

The lubricating device of the instant invention is described with reference to the accompanying drawings in which:

FIG. 1 "is a longitudinal section of a sewing machine arm including the lubricating device;

FIG. 2 is a sectional view taken on the line II-II of FIG. 1;

FIG. 3 shows a detail seen in FIG. 1;

FIG. 4 is an enlarged view of a detail of FIG. 1;

FIG. 5 is a sectional view taken on the line VV of FIG. 4;

FIG. 6 is a polar diagram of the oil pressures in the interstice between the bushing and sewing machine shaft.

The arm 1 of the sewing machine carries a main shaft 2 which is driven in rotation in the direction of the arrow X by a driving means not shown. Shaft 2 carries a fixed disc 3 which contacts the oil 4 contained in the lower part of the reservoir 5. The reservoir 5 fixed in .the interior of the arm -1 is closed by a cover 6 on the upper portion, said cover having a hole 7 for the purpose of introducing oil into the reservoir 5.

In the reservoir 5 two bushing-s 8 are mounted on the shaft 2 in correspondence with spiral notches 9 and 10 on the shaft 2. The front notch 9 has a lefthand spiral and the rear notch 10 has a righthand spiral so that both notches may send the oil toward the reservoir 5 and thus prevent the oil from dropping out. The bushings 8 (see FIG. 4) are identical but mounted in a special way. At their outer ends the bushing 8 carry oil control rings 11 and within the bushings are conical chambers 12. The taper of the chambers 12 carries the oil toward the holes 13 in the bushings 8 in alignment with holes 14 in the reservoir 5 so that oil may The bushings 8 are provided with holes 15 which connects the chambers 12 with the exterior in order to insure that a possible vacuum does not prevent the flow of oil through the holes 13.

Wicks 16, 17 (see FIG. 1) protected by sheaths 18, 19 make sliding contact with the disc 3 in the reservoir. The wicks pass through the walls of reservoir 5 with wick 16 passing to a bored cap 20 fixed to .the stiffening rib 21 of the arm 1 and with wick 17 passing to a shaped plate 22.

Front busing 23 for shaft 2 is fixed to the stiffening rib 21, and two shoulder rings 24, 25 press against the bushing 23. The rear ring 24 is fixed to the shaft whereas the front ring 25 is adjacent to a counterweight 26 which in turn is pinned to the shaft 2. The bushing 23 is divided into two areas 27, 28 having different internal diameters, the front area 27 with the larger diameter bears the roller bearings 29 on shaft 2, and the rear area 28 with the smaller diameter embraces the shaft 2 which is provided with a righthand spiral groove 30. A wick 31 carried in axial grooves 32, 33 in bushing 23 receives oil from wick 16 thereby lubricating the bearings 29 and the surfaces of contact between the bushing 23 and the shoulder rings 24, 25. The groove 30 on shaft'2 carries oil toward the front area 27 of bushing 23. Excess oil falls to the lower wall 34 of the arm 1 and collects in oil sump 35 provided in the lower wall of arm 1.

The shaped plate 22 (see FIGS. 1-3), which is reached by wick 17, is fixed to the front part of arm 1 by means of screws 36. The shaped plate 22 is provided with holes 37 within which wick 17 is fitted in order that it may form the

loops

38, 39, 40, and 41 in correspondence with the curved surfaces of the slot 42 provided for the lubrication of the

pins

43, 44, and 45 of the conventional thread take-up lever 46 and of the large end 47 of the connecting rod 48 which controls the conventional reciprocating movements of the needle bar' 49 carried by bushings 50 of the support 51.

As seen in FIG. 2 a wick 52 enters the oil sump 35 and fits into a hole 53 in plate 54 fixed to the stiffening rib 55 of the arm 1. The Wick 52 forms a loop 56 which contacts the curved surface of the slot 57 on the small end 58 of the connecting rod 48 and lubricates the coupling surfaces of said small end of the connecting rod with the block 59 fixed to the needle bar 49, and the sliding surfaces of block 59 within the guide 60 fixed to the stiffening rib 55.

A felt 61 held by springs 62 is provided to insure lubrication of the bushings 50 slidingly carrying the needle bar 49. The felt 61 absorbs oil from the oil mist created by the motion of machine parts within the front part of the arm 1.

In order that the oil may be thrown out of the slot 63 provided for the passage of the thread take-up lever 46 the conventional guard plate 64 fixed on the front part of the slot 63 (FIG. 2) carries a run channel for gathering the oil and passing it into the sump 35 provided with a felt 66. Should conventional means (not shown) allow the support.51' for the needle bar 49 to oscillate around a fulcrum 67 within a slot 68 in the arm 1 (FIG. 1), the end 69 of felt 66 comes out of the oil sump 35 and adheres to support 51 so as to prevent the oil mist from passing through the slot 68. A plate v70, fixed to the'stiffening rib 55 of the arm 1, enters the sump 35 and presses on the felt 66 and on the wick 52. The plate 70 carries the bored end 71 in which is fitted the tube 72 which connects to the inlet duct 73 of the suction pump 74 contained in the reservoir 5.

The body of the suction pump 74 (see FIG. 4) is consituted by a bushing 75 embracing the shaft 2 in a spaced position in relation to the disc 3 and the walls of the reservoir 5 and which carries externally an extension 76 in the fork 77 of which is engaged the smaller diameter portion 78 of a pin 79 fixed to the reservoir 5. The smaller diameter portion 78 on the pin 79 allows the small axial displacements of the bushing 75 which are necessary for its self-centering with reference to a section 80 of the shaft 2 from which point there originates a groove 81 having a righthand spiral and directed towards the front part of the bushing, and a groove 82 having a left hand spiral and directed towards the rear part of the bushing. The inlet tube 73 is connected to the radial hole 83 in 3 the center of the bushing 75 adjacent to the section 80 of shaft 2. An additional radial hole 84 is provided in the middle of the length of bushing 75 substantially opposite to hole 83, receiving a duct 85 submerging directly into the body of oil 4 contained in the reservoir 5.

This duct 85 is adapted to prime pump 74. When rotation of shaft 2 is started a vacuum is generated within the section 80 which is not sufficient to suck the oil from the sump 35 since groove sections 81 and 82 are filled with air. The before-mentioned vacuum is however sufficient to suck, through the short pipe 85, oil from the reservoir 5 which then enters the pump and expels the air contained in groove sections 81 and 82. A perfect seal is thereby obtained in pump 74 so that the vacuum of section 80 is increased to an amount sufiicient to now also suck oil from sump 35. The circulation of the oil through the bushing increases the space in the central area of bushing 75 adjacent the duct 73 which allows the oil which has collected in the sump 35 to be filtered through the felt 66 and to be returned to the reservoir 5 through the tube '72 and pump 74. In order to reduce the suction effect of pump 74 there is provided a spring 86 within reservoir 5 with spring force acting substantially upwards on the central part of bushing 75 (see FIG. 5 During rotation of shaft 2 the force of the spring 86 is balanced by the pressure of the oil film circulating in the interstice existing between the shaft 2 and the bushing 75. These pressures are distributed, in accordance with known theories of lubrication, as shown in the polar diagram illustrated in FIG. 6.

The angular position of spring 86 with respect to

ducts

83 and 85 is chosen in such a manner that the force by which spring 86 acts on bushing 75 provides a maximum gap between shaft 2 and bushing 75 substantially in the vicinity of duct 83. As a consequence of this the width of the gap between shaft 2 and bushing 75 is determined in the vicinity of duct 85 practically only by the suction action exerted by groove sections 81 and 82, whereas the width of the gap between shaft 2 and bushing 75 in the vicinity of duct 83 is determined by the suction action exerted by groove sections 81 and 82 and additionally by the influence of the force exerted by spring 86.

I claim as my invention:

1. In a sewing machine the combination comprising an oil reservoir, means for distributing the oil from said reservoir to the parts of the machine to be lubricated, a sump for the oil, and a suction pump for conveying the oil from said sump to said reservoir, said suction pump comprising a bushing arranged in said reservoir above the oil level and having at least one first and one second substantially radial hole, a shaft provided with a peripheral helical groove having a first section and a second sec-v tion each wound in an opposite sense, said bushing embracing said groove so that said holes communicate with that groove, at least one first and one second suction duct connected to said first and said second hole, said first hole and said first duct communicating with said sump and claim 1 wherein said means for distributing the oil fromsaid reservoir to the parts of the machine to be lubricated comprises a disc fixed to said shaft, said disc contacting the oil in said reservoir, a pair of wicks contacting said disc for carrying lubricating oil to parts of the machine, and wherein said disc is spaced from said bushing.

3. In a sewing machine the combination of claim 1, wherein said groove extends over the entire portion of said shaft as embraced by said bushing, said first and said second groove section each extending over substantially half of said portion, said holes being located opposite to each other and substantially in the middle of the length of said portion.

4. In a sewing machine the combination according to claim 1, comprising furthermore a spring means interconnected between the outer surface of said bushing and the inner surface of said reservoir, said spring means pressing on said bushing in the vicinity of said second hole so that a negative pressure is generated in the area of said first hole and a substantially atmospheric pressure is generated in the area of said second hole when said shaft is rotated. v

5. In a sewing machine, the combination according to claim 1, wherein said shaft is provided with an additional annular peripheral groove located between said first and said second groove section, means being provided to prevent rotation of said bushing and to allow limited axial movement of said bushing to assure self-alignment of said holes with said annular groove.

6. In a sewing machine, the combination according to claim 1, wherein a further peripheral helical groove is arranged on said shaft at each side of the portion of said shaft provided with said first and second groove sections, said further grooves being wound opposite to the respective adjacent groove sections, a pair of sealing bushings being located in opposite side walls of said reservoir embracing corresponding portions of said shaft provided with said further grooves.

7. In a sewing machine the combination according to claim 1 further comprising a felt oil filter in said sump, a plate in said sump contacting said felt oil filter, and a tube contacting said plate and connected to the first said duct.

References Iited by the Examiner UNITED STATES PATENTS 1/1956 Attwood 112256 6/1958 Ciecor 112256

Claims

1. IN A SEWING MACHINE THE COMBINATION COMPRISING AN OIL RESERVOIR, MEANS FOR DISTRIBUTING THE OIL FROM SAID RESERVOIR TO THE PARTS OF THE MACHINE TO BE LUBRICATED, A SUMP FOR THE OIL, AND A SUCTION PUMP FOR CONVEYING THE OIL FROM SAID SUMP TO SAID RESERVOIR, SAID SUCTION PUMP COMPRISING A BUSHING ARRANGED IN SASID RESERVOIR ABOVE THE OIL LEVEL AND HAVING AT LEAST ONE FIRST AND ONE SECOND SUBSTANTIALLY RADIAL HOLE, A SHAFT PROVIDED WITH A PERIPHERAL HELICAL GROOVE HAVING A FIRST SECTION AND A SECOND SECTION EACH WOUND IN AN OPPOSITE SENSE, SAID BUSHING EMBRACING SAID GROOVE SO THAT SAID HOLES COMMUNICATE WITH THE GROOVE, AT LEAST ONE FIRST AND ONE SECOND SUCTION DUCT CONNECTED TO SAID FIRST AND SAID SECOND HOLE, SAID FIRST HOLE AND SAID FIRST DUCT COMMUNICATING WIT SAID SUMP AND SAID SECOND HOLE AND SAID SECOND DUCT COMMUNICATING WITH SAID RESERVOIR.