US2961984A

US2961984A - Looper lubricating system for sewing machines

Info

Publication number: US2961984A
Application number: US713485A
Authority: US
Inventors: Reeber Rudolf; Irmscher Paul Walter
Original assignee: GM Pfaff AG
Current assignee: GM Pfaff AG
Priority date: 1957-02-13
Filing date: 1958-02-05
Publication date: 1960-11-29
Anticipated expiration: 1977-11-29

Description

Nov. 29, 1960 R. REEBER ETAL 2,961,984

LOOPER LUBRICATING SYSTEM FOR SEWING MACHINES Filed Feb. 5, 1958 4 Sheets-Sheet 1 Nov. 29, 1960 R, REEBER ErAL' 2,961,984

LOOPER LUBRICATING SYSTEM FOR SEWING MACHINES l Filed Feb. 5. 1958 4 Sheets-Sheet 2 Nov. 29, 1960 R. R'l-:EBER E'r AL 2,961,984

LOOPER LUBRXCATING SYSTEM FOR SEWING MACHINES Filed Feb. 5, 1958 4 Sheets-Sheet 3 Nov. 29, 1960 R. REEBER Erm. 2,961,984

LOOPER LUBRICATING SYSTEM FOR SEWING MACHINES Filed Feb. 5, 1958 4 Sheets-Sheet 4 NFEN'OPS United States Patent O LOOPER LUBRICATING SYSTEM FOR SEWING MACHINES Ridolf Reeber and Paul Walter Irmscher, Kaiserslautern,

Pfalz, Germany, assignors to G. M. Pfaff A.G., Kaiserslautern, Pfalz, Germany Filed Feb. 5, 1958, Ser. No. 713,485

Claims priority, application Germany Feb. 13, 1957 6 Claims. (Cl. 112M256) The invention relates to the lubrication of sewing machines and more particularly to the lubrication of the looper race of the machines.

For this purpose a lubricant is led from a lubricant container, and its supply to the looper race in controlled by means of a valve disposed in the lubricant supply line.

Several requirements must be met in connection with the lubrication of loopers, and it is dicult to establish harmony in the arrangement of the components necessary to meet these requirements. It is necessary, on the one hand, especially where rapidly rotating sewing machines are concerned, to provide the looper race with an ample supply of lubricant in order to avoid excessive heating and the results of wear. On the other hand, it is necessary to avoid that the lubricant in the looper race comes into contact with the sewing thread. If the supply of lubricant is too strongly reduced for that purpose a black mass of lubricant remnants and of metallic wear is formed in the looper race. Although the thread absorbs only small quantities of this mass during sewing, it is suicient to blacken the seam formation. If the lubricant supply lis completely stopped, the so-called black sewing ceases, but the sewing machine operates with a `dry looper race which is permissible only for a short period of time and below a certain number of revolutions.

It is, therefore, one object of the invention to provide va clean seam by maintaining the quantity of lubricant supplied to the looper race within such limits as are determined at the lower end by the start of the so-called black sewing and at the upper end by the formation of visible lubricant spots.

Said limits depend primarily on the type of the material being sewed. For example, when very sensitive materials are being sewed, these limits concide, so that not even the most careful dosing of the lubricant supply insures obtaining a clean seam formation. It is therefore necessary to sew sensitive materials of this kind with a -dry looper race which, however, as previously pointed out, can only be effected with a slowly rotating machine.

It is, therefore, another object of the invention I'to-provide a looper lubricating system where the lubricating supply to the looper race is controlled in accordance with Ithe requirements established by the magnitude of the number of rotations.

In accordance with the invention this object is achieved by means of a shifting system which depends for operation on the centrifugal effect obtained after a predetermined number of rotations is attained. Said shifting device is suitably connected to a rapidly rotating shaft of the machine, and it controls a valve which is arranged in the lubricant `supply lead to regulate the lubricant supply, i.e., it opens and closes the valve. The lubricant supply to the looper race thus starts only when this number of rotations is exceeded, and it can be adjusted in such a manner that the range of numbers of rotation above that number insures sufficient lubrication, While .on the "ice other hand, it is within the limits dictated by the cleanliness of the seam. The duration of the lubricant supply is thus always shorter than the running time of the looper so that when many short seams are being sfewed, the looper race is not flooded.

The centrifugal shifting device is suitably providedwith a constant shifting thrust and operates the valverby way of an intermediate member, the effective lengthof which can be adjusted in very small steps. In this manner it is possible to accurately dose the lamount of lubricant which passes through the opened valve. f

A particularly suitable system for the precise adjusting of the intermediate member, which is applicable also in valves having the shortest possible operating path and,

' therefore, small structural lengths, and the advantage of a setting member which always remains in the same place is provided. Thus, in accordance with a further object the invention provides that between ,a -thrust member of the centrifugal shifting device which moves in an axial direction and Ian operating pin of the valve, `the axis" of which is offset relative to the axis of the thrust member, the free end of a lever is disposed, which is linked at the other end to a threaded spindle at a linkage point which is removed by a distance several times that of the oiset, which spindle is adjusted by means of `a nut and extends parallel to the shifting and the operating axes.

Further objects and details of the invention and the method of operation of the new lubricating system will become more apparent from the following specification, if reference is had to the accompanying drawings in which Fig. l is a front elevation of acsewing machine with parts broken away to expose the lubricating system;

Fig. 2 is a longitudinal section through the essential parts Of the lubricating system; l

Fig. 3 is a section taken along the line III-III ofl-Tig. 2; `Y

Fig. 4 illustrates three steps, a, b, and c, of the course of the movements when the lubricant supply is opened, and Y .Fig 5 illustrates the course of movements in a manner similar to Fig. 4 but with the intermediate member adjusted differently. i

The arm 1 of the sewing machine is provided with a container or tank 2 (Fig. l) which is covered with a removable lid 3 to permit filling with lubricant. A lubricant supply line 4 leads from tank 2 to a valve 5 and thence to a further lubricant supply line 6 :to the looperr7. The lubricant supply line 6 is connected to a lubricant dropping member 8 which extends into a lubricant receiving portion or shell 9 ofthe looper 7 whence the lubricant is conducted in a known manner to the-looper race.

The valve 5 is secured to a molded lportion of the base plate 11 of the machine. It has a bore 12 which cornmunicates with a bore 13 of smaller diameter. In this manner a seat 14 is formed for a valve ball 15. The valve ball 15 is pressed against its seat 14 rby a pressure spring 16 which is supported against the nipple 17 of the-lubricant supply line 4.

A bore 18 leads radially outwardly from the bore A13 and a threaded nipple 19 of the lubricant feed line 6V is connected thereto. An operating pin 20 for the valve 5 extends into the bore 13 and is surrounded by a gasket ring 21 which prevents the undesirable exit of thev lubricant from the bore 13 along the operating pin ,20.v lAn insert member 22 provided with a bore for the operating pin 20 secures the sealing gasket 21 in its position. The end of the operating pin 20 projects from the insert V22 and serves for raising the valve ball 15 from its seat 14 against the pressure of the spring 16 in a manner to permit a larger or smaller flow of lubricant through the valve 5.

The looper 7 is carried by the looper shaft 23 which runs in the

ball bearings

24 and 25, which in turn are provided in a housing 26 secured -ina molded portion 27 of the base plate 11 of the machine by means of a set j screw 28. The end of the looper shaft 23 which is remote from the looper 7 carries a toothed gear 29 which meshes with a gear 30 on shaft 31 which in turn is mounted for rotation in a ball bearing 32 disposed in the molded portion 10.

t Two

shells

33 and 34 having conical conformations are provided upon the looper shaft 23. The shell 33 is securely fastened upon the looper shaft 23 by means of a pin while shell 34 is mounted for axial movement upon the looper. shaft 23 by means of a pin 35 which extends through a longitudinal slot 36 in the shaft. The abutment of the pin 35 at the end of longitudinal slot 36 limits the axial movement.

I An axial bore 37 is provided in the looper shaft 23 at the end remote from the looper 7 into which a shifting or thrust rod 38 is mounted which has a piston shaped end 39 abutting against the pin 35. At its other end thrust rod 38 is mounted in a bore of the counter bearing 40 for a spring 41 and extends beyond the end of the looper shaft 23. 'I'he spring 41 is disposed between counter bearing 40 and the piston shaped end 39 of the thrust rod 38 and presses the

shells

33 and 34 against each other by way of pin 35. The counter bearing 40 is in threaded engagement with the end portion of bore 37. In this manner it is possible to adjust the pressure of the spring 41 and thus the force with which the

shells

33 and 34 are pressed against each other.

Shells

33 and 34 enclose halls 42 which as a result of the centrifugal force developed by the rotation of the looper shaft 23 have a tendency to force

shells

33 and 34 apart. The force of spring 41 however opposes this separation as long as this force is greater than that exerted by balls 42. If the centrifugal force overcomes that of the spring the radial distance of balls 42 from the axis of rotation increases and consequently also the centrifugal force whereupon the

shells

33 and 34 move apart suddenly until the pin 35 abuts the end of the longitudinal slot 36. When the number of rotations decreases the opposite process takes place, i.e. the

shells

33 and 34 suddenly move together.

It is possible for the shell 34 to move only relative to the looper shaft 23 in which connection the movement is transferred to the pin 35 and to the thrust rod member 38. Thus the thrust rod executes a thrust of constant length corresponding to the length of the longitudinal slot 36 when the number of rotations corresponding to the pressure of spring 41 is exceeded or decreased.

j Thrust member 38 and operating pin 20 are oset laterally with respect to one another as indicated in Figs.

3 to 5. Between the two the free end 43 of lever 44 is disposed which is linked by means of a bolt 45 to a threaded spindle 46 and which is guided in a bifurcated member 47 secured to molded portion 10. The threaded spindle 46 is journalled for longitudinal sliding in a sleeve 48 which in turn is secured to molded portion 27 of the base plate 11 of the machine by means of a set screw 49. .A pressure spring 51 engages an abutment 50 of the spindle 46 and rests with its other end against the sleeve 48. The pressure spring 51 upon the threaded spindle 46 is tightened against the sleeve by means of a knurled nut 52. Rotating the nut 52 permits shifting of the spindle 46 and thus of bolt 45 which serves as the linkage point for lever 44 in a manner that pressure spring 51 permits not only adjustment without tolerance but also provides a frictional force which secures the adjusting nut 52 against unintentional setting.

The free end 43 of lever 44 is provided at its area of contact with the operating pin 20 with an abutment plane 53 (Fig. 4) which is convexly curved. At the contact area with the thrust member 38 a pressure member 55 is 4 provided which is movable about a pivot bolt 54 and presents a plane abutment surface 56.

In the position of rest the thrust rod 38 is in the phase a indicated in Figs. 4 and5.

As the shifting thrust is executed rod 38 first moves into engagement with the pressure member 55 so that this member adjusts itself with its abutment plane 56 perpendicular to the `axis of the thrust rod (phase b). Continuing movement of the thrust rod 38 causes pressure member 55 to move the free end 43 of lever 44 and carry along the operating pin 20 and in this connection the extent of the valve opening thrust depends upon the position of the linkage point of lever 44. The position of that point determines the angular location of lever 44 and thus the effective length between

engagement planes

53 and 56 of the intermediate member which is constituted of the

parts

43 and 55. rIhe effective length of the

intermediate member

43, 55 is greater in Fig. 4 as in Fig. 5. Ihe path of the operating pin 20 is also greater by the same amount because the thrust member 38 in both instances effects the same amount of thrust. The effective length of the intermediatae

member

43, 55 can also be readlly and accurately changed with the thrust member 38 in operative position by turning the adjusting nut 52.

Having now described our invention with reference to the embodiment illustrated herein, we do not wish to be limited thereto, but what we desire to protect by Letters Patent is set forth in the appended claims.

We claim:

1. In a sewing machine of the type having a looper drive shaft and a looper supported endwise of said drive shaft and having a lubricant receiving portion, a lubricating system for the looper race comprising a lubricant container, a feed line extending from said container to said receiving portion, and automatically operative feed control means provided in operative relationship to said feed line and having a feed control portion including a valve or the like associated with said feed line and a centrifugally actuated shifting portion mounted on said looper shaft and having a portion movable axially of said shaft and operatively connected to said valve, said shifting portion comprising a centrifugal device associated with said shaft and responsive to the centrifugal force imparted thereto by said shaft.

2. In a sewing machine of the type having a looper drive shaft and a looper supported endwise of said drive shaft and having a lubricant receiving portion, a lubricating system for the looper race comprising a lubricant container, a feed line extending from said container to said receiving portion, and automatically operative feed control means provided in operative relationship to said feed line and having a feed control portion including a valve or the like associated with said feed line and a cen trifugally actuated shifting portion mounted on said looper shaft and having a portion movable axially of said v shaft and operatively connected to said valve, said shifting portion comprising a centrifugal device associated with said shaft and responsive to the centrifugal force imparted thereto by said shaft, and a force transfer means having a portion of adjustable effective length disposed intermediate said shifting portion and said valve and said shifting portion including a thrust member havling one end in operative engagement with said transfer means and being movable over a path of predetermined length.

3. In a sewing machine of the type having a looper drive shaft and a looper supported endwise of said drive shaft and having a lubricant receiving portion, a lubricating system for the looper race comprising a lubricant container, `a feed line extending from said container to said receiving portion, and automatically operative feed control means provided in operative relationship to said feed line and having a feed control portion including a valve or the like associated with said feed line and a centrifugally actuated shifting portion mounted on said looper shaft and having a portion movable axially of said shaft and operatively connected to said valve, said shifting portion comprising a centrifugal device associated with said shaft and responsive to the centrifugal force imparted thereto by' said shaft, `and a force transfer means having a portion of adjustable effective length disposed intermediate said shifting portion and said valve, said shifting portion including a thrust member having one end in operative engagement with said transfer means and being movable over a path of predetermined length, said thrust member being movable axially of said shaft and said control portion including a valve having an operating pin extending parallel to and offset relative to the axis of said thrust member, and said force transfer means including an adjustable threaded spindle mounted on the base of the machine, and extending parallel to the axes of said thrust member and said operating pin at a distance several times the magnitude of the offset distance and a lever defining said portion of adjustable effective length at its free end intermediate said thrust member and said operating pin and having its other end linked to said adjustable threaded spindle.

4. In a sewing machine of the type having a looper drive shaft and a looper supported endwise of said drive shaft and having a lubricant receiving portion, a lubricating system for the looper race comprising a lubricant container, a feed line extending from said container to said receiving portion, and feed control means provided in operative relationship to said feed line and having a feed control portion associated with said feed line and a centrifugally actuated shifting portion operatively connected to said feed control portion, said shifting portion comprising a centrifugal device associated with said shaft and responsive to the centrifugal force imparted thereto by said shaft, and a force transfer means having a portion of adjustable effective length disposed intermediate said shifting portion and said feed control portion, said shifting portion including a thrust member having one end in operative engagement with said transfer means and being movable over a path of predetermined length, said thrust member being movable axially of said shaft and said control portion including a valve having an operating pin extending parallel to and offset relative to the axis of said thrust member, and said force transfer means including an adjustable threaded spindle mounted on the base of the machine, and extending parallel to the axes of said thrust member and said operating pin at a distance several times the magnitude of the offset distance and a lever defining said portion of adjustable effective length at its free end intermediate said thrust member land said operating pin and having its other end linked .to said adjustable threaded spindle, said lever presenting a convex contact surface proximate said operating pin and a pivotally mounted pressure member having an engagement surface disposed endwise of said thrust member, and said thrust member being rotatable with said shaft.

5. In a sewing machine of fthe type having a looper drive shaft and a looper supported endwise of said drive shaft and having a lubricant receiving portion, a lubricating system for the looper race comprising a lubricant container, a feed line extending from said container to said receiving portion, and feed control means provided in operative relationship to said feed line and having a feed control portion associated with said feed line and a centrifugally actuated shifting portion operatively connected to said feed control portion, said shifting portion comprising a centrifugal device associated with said shaft and responsive to the centrifugal force imparted thereto by said shaft, and a force transfer means having a portion of adjustable effective length disposed intermediate said shifting portion and said feed control portion, said shifting portion including a thrust member having one end in operattive engagement with said transfer means and being movable over a path of predetermined length, said thrust member being movable axially of said shaft and said control portion including a valve having an operating pin extending parallel to and offset relative to the axis of said thrust member, and said force transfer means including an adjustable threaded spindle mounted on the base of the machine, and extending parallel to the axes of said thrust member and said operating pin at a distance several times the magnitude of the offset distance and a lever defining said portion of adjustable effective length at its free end intermediate said thrust member and said operating pin and having its other end linked lto said adjustable threaded spindle, said threaded spindle presenting a first abutment and being mounted on the base of the machine and a spring biasing said threaded spindle having one end in engagement with said first abutment and the other end in engagement with a second abutment defined on said machine base.

6. In a sewing machine of the type having a looper drive shaft and a looper supported endwise of said drive shaft and having a lubricant receiving portion, a lubricating system for the looper race comprising a lubricant container, a feed line extending from said container to said receiving portion, and feed control means provided in operative relationship to said feed line and having a feed control portion associated with said feed line and a centrifugally actuated shifting portion mounted on said looper shaft and having a portion movable axially of said shaft and operatively connected to said feed control portion, said shifting portion comprising a centrifugal device associated with said shaft and responsive to the centrifugal force imparted thereto by said shaft, and a force transfer means having -a portion of adjustable effective length disposed intermediate said shifting portion and said feed control portion, said shifting portion including a thrust member having one end in operative engagement with said transfer means and being movable over a path of predetermined length, said thrust member being movable -axially of said shaft and said control portion including a valve having an operating pin extending parallel to and offset relative to 'the axis of said thrust member, and said force transfer means including an adjustable threaded spindle mounted on the base of the machine, and extending parallel to :the axes of said thrust member and said operating pin at a distance several times the magnitude of `the offset distance and a lever defining said portion of adjustable effective length at its free end intermediate said thrust member and said operating pin and having its other end linked to said adjustable threaded spindle, said centrifugal device including a portion fixedly secured to said looper drive shaft and a slidable portion movable axially of said shaft in response to centrifugal force and said thrust member being mounted in a hollow portion of said shaft with its other end in operative engagement with said slidable portion and a spring biasing said thrust member in the direction of said slidable portion, and an adjustabie means mounted on said shaft proximate said one end of said thrust member operative to set the spring for a predetermined bias correspond-ing to `a number of revolutions of said centrifugal device above which said thrust member becomes operative.

References Cited in the file of this patent UNITED STATES PATENTS 1,936,372 Waterman Nov. 2l, 1933 1,962,090 Gjerde June 5, 1934 1,968,023 IBijur July 31, 1934 2,283,869 Graesser May 19, 1942 2,453,827 Albero Nov. 16, 1948 2,535,703 Smith et al Dec. 26, 1950