US3340836A

US3340836A - Knee shift mechanisms for sewing machines

Info

Publication number: US3340836A
Application number: US496387A
Authority: US
Inventors: Goebel Gregory
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1965-10-15
Filing date: 1965-10-15
Publication date: 1967-09-12
Anticipated expiration: 1984-09-12

Description

' I BY WITNESS. v v v M. WmcMeo w Sept.' 12, 1967 G. GOEBEL 3,340,836

KNEE SHIFT MECHANISMS FOR SEWING MACHINES Filed Oct. l5, 1965 3 Sheets-Sheet 1 INVENTOR.

Gregory Goebel TTORN EHY WITNESS W Wow ficALCC/wi V I Sept. 12, 1967 G. GOEBEL 3,340,836 I I KNEE SHIFT MECHANISMS FOR SEWING MACHINES Filed Oct. 15, 1965 3 Sheets-Sheet, g

Fig. 2

INVENTOR. Gregory G-oebel A TORNEY G. GOEB'EL KNEE SHIFT MECHANISMS FOR SEWING MACHINES Filed Oct. 15, 1965 Sept. 12, 1967 3 Sheets-Sheet 5 I INVENTOR; Gregory Goebe'l WITNESS United States Patent New Jersey Filed Oct. 15, 1965, Ser. No. 496,387

Claims. (Cl. 112--237) This invention relates to knee shift mechanisms for sewing machines and more particularly to a universal shift mechanism for a sewing machine presser lifter.

In a typical industrial setting, a sewing machine is mounted on a table and is driven by an electric motor which is slung underneath the top of the table. The operator sits in front of the table and controls the motor by a treadle at her feet. At the end of each of many types of sewing operations, the presser foot must be raisedun order to remove fabric which has been sewn and to in sert new fabric which is to be sewn. In addition, it is oftentimes necessary to raise the presser foot during a sewing operation in order to change the position of fabric which is being sewn. Since the operators hands are fully occupied in manipulating the fabric, a knee shift device is provided to lift the presser foot. When a knee shift device is applied to a given sewing machine, the need frequently arises to reorient the position of the knee shift device. Since operators range from very tall to very small, provision must be made for changing the height of the knee pad on the knee shift device. The knee pad is mounted on the end of a depending knee shift lever, and it can be easily visualized that when the knee pad is set for a tall girl much force is required to lift the presser foot because of the short lever arm and consequently decreased mechanical advantage. Conversely, when the knee pad is set for a small girl less force is required because of the long lever arm, but the knee pad must be swung through a long arc. Either a requirement of great force to move the knee pad or a requirement to swing the knee pad through a great arc add greatly to the fatigue of the operator during a day of repetitious operations.

In addition to overcoming the foregoing problems, it would be desirable to be able to change the location of the knee pad transversely relative to the line of feed of fabric on the sewing machine without encountering'the foregoing problems.

In addition to the need for reorientation of a knee shift device applied to one sewing machine, a knee shift device in order to be applicable to any one of a variety of different sewing machines must be capable of reorientation. And, since some sewing machine presser lifters are of the push-type in which a rock shaft in the bracket arm is rocked to lift a presser foot and some sewing machine presser lifters are of the pull-type in which a long lever in the bracket arm is pulled to lift a presser foot, it would be desirable to provide a knee shift mechanism which can be selectively arranged for use with both push-type and pull-type presser lifters in order to take advantage of cost reduction per unit obtainable by production in large volumes, and to reduce the inventory of spare parts required of a user of both push-type and pull-type presser lifters.

It is, therefore, an object of the invention to provide a knee shift mechanism for a sewing machine in which the location of the knee pad can be changed vertically and horizontally without substantially changing the length of the arc through which the knee pad must be swung to operate an intermittently operated mechanism and without substantially changing the force which must be applied to the knee pad.

Another object of the invention is to provide a knee shift mechanism for a sewing machine in accordance with the foregoing object which is readily adaptable for use with both push-type and pull-type presser lifters.

The main feature of the invention is the provision for a knee shift mechanism for a sewing machine in which the pivot means for the knee shift lever is adjustably mounted in a vertical slot in a plate which in turn is adjustably mounted in a horizontal slot in a surface depending from the underside of the sewing machine table. The knee shift lever is connected to an extensible rock arm on a rock shaft by a connecting link which has means for adjusting the distance between a pivot means on the knee shift lever for the link and a pivot means on the extensible rock arm for the link. A second rock arm on the rock shaft is connected to the presser lifter. The foregoing construction enables an operator to change the height of the knee pad and the lateral distance of the knee pad from the line of feed of fabric without changing the arc through which the knee pad must be swung to operate the presser lifter and without changing the force which must be applied to the knee pad to operate the presser lifter. The knee shift mechanism can also be adapted for use with either a push-type presser lifter or a pull-type presser lifter by changing the position of the rock arm which is connected to the presser lifter approximately degrees on the rock shaft. I

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a front elevational view of a sewing machine incorporating a push-type version of the invention;

FIG. 2 is a front elevational view of a sewing machine incorporating a pull-type version of the invention;

FIG. 3 is a cross-sectional view taken substantially along the line 3-3 in FIGS. 1 and 2;

FIG. 4 is a bottom perspective view of the invention of FIG. 1; and

FIG. 5 is a bottom perspective view of the invention of FIG. 2.

With reference to FIGS. 1, 3 and 4 of the drawings, a first modification of the invention is illustrated as incorporated in a conventional sewing machine having a frame which includes a work-supporting bed 10, a hollow standard 11 at one end of the bed, a hollow bracket arm 12 at the top of the standard and overhanging the bed, and a sewing head 13 at the free end of the bracket arm.

The sewing machine is mounted on a table having a top 14 of which only a portion is shown. The table top is formed from a front beam 15, a rear beam 16, and end beams 17 of which only one is shown. The beams surround a rectangular recess 18 in which the bed of the sewing machine is mounted.

Mounted in the bracket arm is an intermittently operated mechanism represented by a presser lifter indicated generally at 19. The presser lifter is a push-type presser lifter of a type disclosed in a United States patent of W. A. Andres, No. 2,529,442, granted Nov. 7, 1950. The presser lifter includes a rock shaft 20 which is journaled in bearings 21 in the bracket arm. The rock shaft has two

rock arms

22 and 23. At the standard end of the rock shaft, a rod 24 pivotally depends from one of the rock arms to the bottom of the standard. At the head end of the rock shaft, a link 25 pivotally depends from the other rock arm. The link connects the presser lifter to a conventional presser device indicated generally at 26.

The presser device includes a presser bar 27 which carries a presser foot 28. The presser bar, and with it the presser foot, are biased downwardly toward the top of the work supporting bed by a spring 29 in the sewing head. The link 25 from the presser lifter is pivotally connected to a collar 30 on the presser bar by a pivot screw 31.

Underneath the table top, there is mounted a knee shift mechanism indicated generally at 32. The knee shift mechanism actuates the rod 24 in the standard which pivotally depends from the presser lifter.

The knee shift mechanism includes a long L-shaped bracket 33 which can be formed from an angle iron and depends from the bottom of the front beam 15 of the table. The long L-shaped bracket is connected to the bottom of the table top by a pair of screws 34, and has an elongated horizontal slot 35.

Connected to the long L-shaped bracket is a small rectangular plate 36 which has an elongated vertical slot 37. The small rectangular plate is connected to the elongated horizontal slot in the long L-shaped bracket by a pair of bolts 38 having washers 39 and nuts 40.

A knee shift lever 41 is pivotally connected to the small rectangular plate by a shoulder bolt 42 having a nut 43 which is housed in a counterbore 44 in the elongated vertical slot 37. A clamp 45 is connected to the free end of the knee shift lever by a setscrew 46, and a knee pad 47 is pivotally connected to the clamp by a horizontal pin 48 which is held in place by a cotter pin 49.

A lug 50 is connected to the long L-shaped bracket 33 by a pair of screws 51 which extend through an elongated vertical slot 52 in the lug and are threaded into a pair of tapped holes 53 (see FIGS. 2 and in the long L- shaped bracket. Opposite from the foregoing lug, a short L-shaped bracket 54 depends from the bottom of the rear beam 16 of the table. The short L-shaped bracket, like the long L-shaped bracket, can be formed from an angle iron, and is connected to the bottom of the table top by a pair of screws 55. A second lug 56 is connected to the short L-shaped bracket by a pair of screws 57 which extend through an elongated vertical slot 58 in the lug and are threaded into a pair of tapped holes (not shown) in the short L-shaped bracket.

The opposed lugs 50 and 56 support a transverse rock shaft 60 which is journaled in bores 61 (of which only one is numbered) in the lugs. The rock shaft is fixed against axial movement by a collar 62 and a cap 63 which are clamped on the rock shaft by

setscrews

64 and 65, respectively. The cap has a transverse bore 66 which carries a rock arm 67. The rock arm is adjustably held in the bore by a setscrew 68.

Both the foregoing rock arm 67 and the knee shift lever 41 have

slots

69 and 70, respectively, for a connecting link 71. The connecting link is pivotally mounted in the slot in the knee shift lever by a screw 72. The connecting link is connected to a pin 73 in the slot in the rock shaft by one of three

oblique notches

74, 75 and 76 in the connecting link which form a first set of notches.

Mounted on the rock shaft 60 between the lugs is a clamp 77. The clampis locked to the rock shaft by a setscrew 78 and has a bore 79 which carries a rock arm 80. The rock arm is adjustably held in the bore by a setscrew 81.

Mounted on the free end of the foregoing rock arm 80 is a cap 82. The cap is locked to the rock arm by a setscrew 83 and has a transverse bore 84 which carries a transverse arm 85 for the rock arm. The transverse arm is adjustably held in the bore by a setscrew 86 and has a cap 87 on its free end. The top surface of the cap supports the rod 24 which depends from the presser lifter.

In the operation of the modification shown in FIGS. 1, 3 and 4, pivotal movement of the knee shift lever 41 in the direction of the arrow rotates the transverse rock shaft 60 counterclockwise as viewed from the front of the sewing machine. The counterclockwise rotation of the transverse rock shaft raises the transverse arm 85 and, with it, the rod 24 which rests on the cap 87 on the transverse arm. The upward movement of the rod rotates the rock shaft 20 in the bracket arm to lift the presser foot by the link 25 at the head end of the rock shaft.

If it is desired to change the height of the knee pad 47 without changing the length of the are through which the knee pad must be swung to lift the presser foot or the force which must be applied to the knee pad, the shoulder bolt 42 which pivotally connects the knee shift lever to the small rectangular plate 36 can be loosened. With the shoulder bolt loosened, the fulcrum of the knee shift lever as embodied in the shoulder bolt can be shifted up or down in the elongated vertical slot 37 as desire-d. A compensating adjustment can be made in the extension of the rock arm 67 from the transverse rock shaft 60 by loosening the setscrew 68.

If it is desired to change the lateral distance of the knee pad 47 from a plane 88 including the line of feed of fabric (not shown) and perpendicular to the work supporting bed also without changing the length of the are through which the knee pad must be swung to lift the presser foot or the force which much be applied to the knee pad, the bolts 38 which connect the small rectangular plate 36 to the long L-shaped bracket 33 can be loosened. With the bolts 38 loosened, the small rectangular plate can be shifted laterally without changing the fulcrum of the knee shift lever 41. To compensate for the lateral movement of the small rectangular plate the connecting link 71 can be connected to the pin 73 in the slot 70 in the rock arm 67 on the transverse rock shaft 60 by a different one of the

oblique notches

74, 75 and 76 in the connecting link.

With reference to FIGS. 2, 3 and 5 of the drawings, a second modification of the invention is also illustrated as incorporated in a conventional sewing machine having a frame which includes a work supporting bed 89, a hollow standard 90 at one end of the bed, a hollow bracket arm 91 at the top of the standard and overhanging the bed, and a sewing head 92 at the free end of the bracket arm.

As in the first modification of the invention, the sewing machine is mounted on a table having a top 93 of which only a portion is shown. The table top is formed from a front beam 94, a rear beam 95, and end beams 96 of which only one is shown. The beams surround a rectangular recess 97 in which the bed of the sewing machine is mounted.

Mounted in the bracket arm is an intermittently operated mechanism represented by a presser lifter indicated generally at 98. The presser lifter is a pull-type presser litter in contrast to the push-type presser lifter 19 with which the first modification of the invention is used. A pull-type presser lifter is disclosed in a United States patent of R. Kaier, No. 2,250,992, granted July 29, 1941. The presser lifter 98 includes a long lever 99 which is pivotally mounted in the bracket arm by a pivot screw 100. The lever is biased counterclockwise as viewed from the front of the machine around the pivot screw by a torsion spring I101. At the standard end of the lever, a rod 102 pivotally depends from a ball-and-socket joint 103 to the bottom of the standard. At the head end of the lever, a link 104 pivotally depends from a pivot pin 105 on the lever. The link connects the presser lifter to a conventional presser device indicated generally at 106.

The presser device includes a presser bar 107 which carries a presser foot 108. The presser bar, and with it the presser foot, are biased downwardly toward the top of the work supporting bed by a coil spring 109. The link 104 from the presser lifter encircles the presser bar underneath a collar 110 on the presser bar.

Underneath the table top, there is mounted a knee shift mechanism indicated generally at 111. The knee shift mechanism actuates the rod 102 in the standard which pivotally depends from the presser lifter. The knee shift mechanism 111 has the same parts, the same arrangement of parts, the same operation, and the same advantages as the knee shift mechanism 32 of the first modification of the invention except as hereinafter described. Like parts have been given like reference numerals.

Relative to the parts and the arrangement of parts, the lug 50 is connected to the long L-shaped bracket 33 at a position which is closer to the standard end of the sewing machine. The screws 51 which connect the lug to the long L-shaped bracket are threaded into a pair of tapped holes 112 (see FIGS. 1 and 4) which are to the right, as viewed from the front of the machine, of the tapped holes 53 for the first modification of the invention. The short L-shaped bracket 54, and with it the second lug 56, are shifted accordingly so as to be in line with the lug 50 to support the transverse rock shaft 60. Correspondingly, the connecting link 71 between the knee shift lever 41 and the rock arm 67 is connected to the rock arm by one of three

oblique notches

113, 114 and 115 in the connecting link which form a second set of notches rather than by one of the three

oblique notches

74, 75 and 76 which form the first set as in the first modification of the invention. The rock arm 80 which is connected to the clamp 77 on the transverse rock shaft 60 extends from the opposite side of the bore 79 in the clamp from the first modification of the invention. A chain 116 is connected between a hole 117 in the rock arm 80 and a hook 118 on the rod 102 which depends from the presser lifter.

In the operation of the modification shown in FIGS. 2, 3 and 5, pivotal movement of the knee lift lever 41 in the direction of the arrow rotates the transverse rock shaft 60 counterclockwise as viewed from the front of the sewing machine. The counterclockwise rotation of the transverse rock shaft pulls the chain 116 and, with it, the rod 102 downwardly. The downward movement of the rod pivots the long lever 99 in the bracket arm in a clockwise direction as viewed from the front of the machine to lift the presser foot by the link 104 at the head end of the lever. The second modification of the invention achieves all of the advantages of the first modification and employs almost all of the same parts.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.

Having thus set forth the nature of the invention, what is claimed herein is:

1. A knee shift mechanism for a sewing machine having an intermittently operated mechanism, a knee shift lever, a knee pad connected to the knee shift lever, and pivot means for the knee shift lever, said knee shift mechanism comprising means for mounting the pivot means, means for changing the location of the pivot means vertically, means for changing the location of the pivot means horizontally, and means for connecting the knee shift lever to the intermittently operated mechanism so that the are through which the knee pad must be swung to operate the intermittently operated mechanism and the force which must be applied to the knee pad remain substantially thesame for all adjusted locations of the pivot means.

2. A knee shift mechanism for a sewing machine having an intermittently operated mechanism, a knee shift lever, a knee pad connected to the knee shift lever and pivot means for the knee shift lever, said knee shift mechanism comprising a surface having a slot and a plate having a slot which crosses the slot in the surface when the plate is superimposed over the surface, said pivot means adjustably mounted in the slot in the plate, said plate in turn adjustably mounted in the slot in the surface, and means for connecting the knee shift lever to the intermittently operated mechanism so that the arc through which the knee pad must be swung to operate the intermittently operated mechanism and the force which must be applied to the knee pad remain substantially the same for all adjusted locations of the pivot means.

3. A knee shift mechanism for a sewing machine having an intermittently operated mechanism, a knee shift lever, a knee pad connected to the knee shift lever and pivot means for the knee shift lever, said knee shift mechanism comprising fastening means for the pivot means, a surface having a horizontal slot and a plate having a vertical slot with a counterbore, said pivot means adjustably mounted in the slot in the plate with the fastening means housed in the counterbore, said plate in turn adjustably mounted in the slot in the surface, and means for connecting the knee shift lever to the intermittently operated mechanism so that the arc through which the knee pad must be swung to operate the intermittently operated mechanism and the force which must be applied to the knee pad remain substantially the same for all adjusted locations of the pivot means.

4. A knee shift mechanism for a sewing machine having an intermittently operated mechanism, a knee shift lever, a knee pad connected to the knee shift lever and pivot means for the knee shift lever, said knee shift mechanism comprising means for mounting the pivot means, means for adjusting the location of the pivot means vertically, means for changing the location of the pivot means horizontally, a rock shaft, means for mounting the rock shaft parallel to the pivot means, a first rock arm on the rock shaft, means for connecting the first rock arm to the intermittently operated mechanism, a second rock arm on the rock shaft, a link, second pivot means for connecting the link to the knee shift lever, a third pivot means for connecting the link to the second rock arm, means for changing the distance between thethird pivot means and the rock shaft, and means for changing the distance between the third and second pivot means.

5. The knee shift mechanism of claim 4 which includes means for changing the location of the rock shaft horizontally.

6. A knee shift mechanism for a sewing machine having an intermittently operated mechanism, a knee shift lever, a knee pad connected to the knee shift lever and pivot means for the knee shift lever, said knee shift mechanism comprising a surface having a slot and a plate having a slot which crosses the slot in the surface when the plate is superimposed over the surface, said pivot means adjustably mounted in the slot in the plate, said plate in turn adjustably mounted in the slot in the surface, a rock shaft, means for mounting the rock shaft parallel to the pivot means, a first rock arm on the rock shaft, means for connecting the first rock arm to the intermittently operated mechanism, a second rock arm on the rock shaft, a link, second pivot means for connecting the link to the knee shift lever, third pivot means for connecting the link to the second rock arm, means for changing the distance between the third pivot means and the rock shaft, and means for changing the distance between the third and second pivot means.

7. The knee shift mechanism of claim 6 which includes means for changing the location of the rock shaft horizontally.

8. A knee shift mechanism for a sewing machine having an intermittently operated mechanism, a knee shift lever, a knee pad connected to the knee shift lever and pivot means for the knee shift lever, said knee shift mechanism comprising fastening means for the pivot means, a surface having a horizontal slot and a plate having a vertical slot with a counterbore, said pivot means adjustably mounted in the slot in the plate with the fastening means housed in the counterbore, said plate in turn.

adjustably mounted in the slot in the surface, a rock shaft, means for mounting the rock shaft parallel to the pivot means, a first rock arm on the rock shaft, means for connecting the first rock arm to the intermittently operated mechanism, a second rock arm on the rock shaft, a link, second pivot means for connecting the link to the knee shift lever, third pivot means for connecting the link to the second rock arm, means for changing the distance between the third pivot means and the rock shaft, and means for changing the distance between the third and second pivot means.

9. A knee shift mechanism for a sewing machine having an intermittently operated mechanism, a knee shift lever, a knee pad connected to the knee shift lever and pivot means for the knee shift lever, said knee shift mechanism comprising means for mounting the pivot means, means for changing the location of the pivot means vertically, means for changing the location of the pivot means horizontally, a rock shaft, means for mounting the rock shaft parallel to the pivot means, a first rock arm on the rock shaft, means for connecting the first rock arm to the intermittently operated mechanism, a second rock arm on the rock shaft, means for changing the extension of the second rock arm from the rock shaft, a link, second pivot means for connecting the link to the knee shift lever, and third pivot means for connecting the link to the second rock arm, said link having means for changing the location of the third pivot means along the link.

10. A knee shift mechanism for a sewing machine having an intermittently operated mechanism, a knee shift lever, a knee pad connected to the knee shift lever and pivot means for the knee shift lever, said knee shift mechanism comprising a surface having a slot and a plate having a slot which crosses the slot in the surface when the plate is superimposed over the surface, said pivot means adjustably mounted in the slot in the plate, said plate in turn adjustably mounted in the slot in the surface, a rock shaft, means for mounting the rock shaft parallel to the pivot means, a first rock arm on the rock shaft, means for connecting the first rock arm to the intermittently operated mechanism, a second rock arm on the rock shaft, means for changing the extensionof the second rock arm from the rock shaft, a link, second pivot means for connecting the link to the knee shift lever, and third pivot means for connecting the link to the second rock arm, said link having means for changing the location of the third pivot means along the link.

References Cited UNITED STATES PATENTS 2,067,038 1/ 1937 Andres ll2237 2,250,992 7/1941 Kaier 112237 2,664,841 1/1954 Hale et al 1l2--237 PATRICK D. LAWSON, Primary Examiner.

Claims

1. A KNEE SHIFT MECHANISM FOR A SEWING MACHING HAVING AN INTERMITTENTLY OPERATED MECHANISM, A KNEE SHIFT LEVER, A KNEE PAD CONNECTED TO THE KNEE SHIFT LEVER, AND PIVOT MEANS FOR THE KNEE SHIFT LEVER, SAID KNEE SHIFT MECHANISM COMPRISING MEANS FOR MOUNTING THE PIVOT MEANS, MEANS FOR CHANGING THE LOCATION OF THE PIVOT MEANS VERTICALLY, MEANS FOR CHANGING THE LOCATION OF THE PIVOT MEANS HORIZONTALLY, AND MEANS FOR CONNECTING THE KNEE SHIFT LEVER TO THE INTERMITTENTLY OPERATED MECHANISM SO THAT THE ARC THROUGH WHICH THE KNEE PAD MUST BE SWUNG TO OPERATE THE