US2729179A - Sewing machine bearing and pitman construction - Google Patents

Sewing machine bearing and pitman construction Download PDF

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Publication number
US2729179A
US2729179A US310295A US31029552A US2729179A US 2729179 A US2729179 A US 2729179A US 310295 A US310295 A US 310295A US 31029552 A US31029552 A US 31029552A US 2729179 A US2729179 A US 2729179A
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Prior art keywords
pitman
shaft member
crank
strap
portions
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US310295A
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English (en)
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John G Attwood
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Union Special Machine Co
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Union Special Machine Co
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Priority to US310295A priority Critical patent/US2729179A/en
Priority to FR1080957D priority patent/FR1080957A/fr
Priority to DEU2381A priority patent/DE953482C/de
Priority to GB25675/53A priority patent/GB726638A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C9/00—Bearings for crankshafts or connecting-rods; Attachment of connecting-rods
    • F16C9/04—Connecting-rod bearings; Attachments thereof
    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B69/00—Driving-gear; Control devices
    • D05B69/30—Details
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C3/00—Shafts; Axles; Cranks; Eccentrics
    • F16C3/04—Crankshafts, eccentric-shafts; Cranks, eccentrics
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C7/00—Connecting-rods or like links pivoted at both ends; Construction of connecting-rod heads
    • F16C7/02—Constructions of connecting-rods with constant length
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2340/00—Apparatus for treating textiles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/21—Elements
    • Y10T74/2142—Pitmans and connecting rods
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/21—Elements
    • Y10T74/2173—Cranks and wrist pins

Definitions

  • the top operating speed is limited by failure of cooperating relatively moving parts due to misalignment.
  • failure of the ball crank in the needle lever mechanism is one of the chief factors in limiting the top operating speed.
  • the needle bar lever is oscillated about a pin in the center of the overhanging arm by means of a pitman interconnecting one end of the needle bar lever and the lower driving shaft.
  • Burning and binding due to misalignment in a crank or eccentric and pitman assembly employing needle bearings may be reduced by removing one of the needles from the hearing. In such a construction, those forces which produce binding will urge all of the remaining needles of the bearing away from the point at which binding would normally occur, leaving the space of the omitted needle at that point. While this arrangement affords some improvement, it is by no means completely satisfactory in that the construction is noisy and the operating speeds attainable without undue burning and binding are not sufiiciently great.
  • the principal object of the present invention has been to provide a novel and improved pitman and bearing construction for sewing machines which will permit the attainment of higher operating speeds.
  • Another object of the invention has been to provide an improved crank and pitman construction for fiat bed sewing machines operating at relatively high speeds.
  • a further object of the invention has been to provide an improved eccentric and pitman construction for high speed sewing machines.
  • a feature of the invention has been to provide a bearing construction in which substantial shake, i. e., flexibility 2,729,179 Patented Jan. 3, 1956 or freedom of movement allowing misalignment without burning and binding, is achieved.
  • the driving connections for one or more of the stitch forming and work feeding elements of a sewing machine with a shaft member, means to impart rotary motion to the shaft member, an oscillatable ele ment, a pitman, a drive connection with the shaft member, involving a crank or eccentric on the shaft member and a strap for connecting the end of the pitman to the crank or eccentric, and a coupling means, such as a ball and strap connection, for connecting the other end of the pitman to the oscillatable element whereby rotary moing assembly interconnecting the same;
  • Fig. 4 is an enlarged plan view of the main driving shaft and crank of the machine of Fig. 1;
  • Fig. 3 is an enlarged side elevational view of the main driving shaft and crank
  • Fig. 6 is an enlarged cross sectional view taken along the line 66 of Fig. 4;
  • Fig. 7 is an enlarged cross sectional view taken along the line 7-7 of Fig. 5;
  • Fig. 8 is a view similar to Fig. 4 and illustrating a modification of the crank element construction according to the invention
  • Fig. 9 is a view similar to Fig. 5 and illustrating the modification shown in Fig. 8;
  • Fig. 10 is an enlarged cross sectional view taken along the line 10-10 of Fig. 9;
  • Fig. 11 is an enlarged cross sectional vie the line 1111 of Fig. 8;
  • Fig. 12 is an elevational view of an adjustable eccentric and bearing construction, according to the invention, for connecting a shaft and pitman, the shaft being shown in section;
  • Fig. 13 is a view similar to Fig. 12 but with the shaft and eccentric assembly shifted relative tothe pitman and with the eccentric also shown in section;
  • Fig. 14 is a cross sectional view taken along the line 14-14 of Fig. 13;
  • Fig. 15 is a cross sectional view taken along the line 15- 15 of Fig. 12;
  • Fig. 16 is a cross 16-16 of Fig. 13;
  • Fig. 17 is a view partly in elevation and partly in cross section, of a modified form of adjustable eccentric w taken along sectional view taken along the line and bearing construction on a shaft, according to invention, for driving a pitman;
  • Fig. 18 is a cross sectional view taken along the line 18-18 of Fig. 17;
  • Fig. 19 is a cross sectional view taken along the line 19-19 of Fig. 17;
  • Fig. 20 is an enlarged detail view, partly in cross section, illustrating a modification, according to the invention, of the crank portion of a shaft and its associated bearing and strap elements for driving a pitman",
  • Fig. 21 is a cross sectional view taken along the line 21-21 of Fig. 20;
  • Fig. 22 is a cross sectional view taken along the line 22.22 of Fig. 20.
  • the sewing ma chine comprises a frame having a hollow base 20 and a hollow vertical standard 21 rising therefrom adjacent one end of the base and communicating therewith. Extending laterally from and supported by said standard is a hollow arm 22 which overhangs the base and terminates at its free end in a hollow head, 23. Mounted the in the upper and lower walls of the head 23 are a pair of bushings 24 and 25, respectively, and journaled in these bushings for generally vertical reciprocation is a needle bar 26. The needle bar 26 is provided at its lower end with suitable needle holding means 27 adapted to retain one. or more needles. Mounted on the needle bar is a collar 28' held in place by a pair of screws 29 and provided with a lug 30 to which one end of a link 31 is pivotally attached.
  • a pair of bushings 32 are mounted in the front and back walls of the arm 22 and a shaft 33 is journaled for rocking motion in the bushings 32.
  • a needle lever 34 mounted on the shaft 33 and adapted for rocking movement is a needle lever 34.
  • the left hand end of the lever 34 is pivotally connected to the link 31 bymeans of' a pin 35.
  • the right hand end of the lever 34 is provided with a ball stud 36 which is secured to the lever in any suitable way, as by means of the set screws shown.
  • the lever 34 is driven by a pitman or connecting rod 37 having attached to its upper end a split, socket-like strap 38 having a spherical seat which cooperates with the ball stud 36.
  • the pitman 37 as best shown in Fig. 2, preferably comprises two generally vertical, hollow tubular members'39 and 40 disposed on opposite sides of the ball stud 36. Members 39 and 40 are provided at their upper ends with internally threaded cap elements 39a and 40a, respectively.
  • a drive shaft Journaled in the base 20 is a drive shaft provided with a crank 51.
  • a crank 51 Mounted on the shaft 50 toward its right hand end outside the base 20 is a combined hand wheel and belt pulley51a for driving the shaft 50.
  • the pulley 51a may be driven by a belt from a conventional transmitter unit, not shown.
  • The, crank shaft 50 in addition to operating the needle bar driving connections in a manner to be described, also'operates various stitch forming and work feeding elements located within the base 20.
  • the members 39 and 40 of pitman 37 are provided with cap elements 3% and 40b at their lower ends, these beingwelded or otherwise secured to the members and being provided with threaded extensions 39c and 400 for cooperation with a split strap 52.
  • the threaded extensions pass freely through the section of the strap and are'screwed' into the lower section.
  • the extensions 39c and- 400 terminate in oilsplashers 3% and 40e, respectively.
  • Strap 52 provides an annular bearing surface for the pitman 37 and is operatively connected to a crank element 53 by a plurality of closely spaced roller or needle bearing elements 54. As best shown in Fig. 3, the crank element 53 extends between cheeks or flanges 55 and 56, respectively, of crank arms 57 and 58, respectively.
  • the bearings 54 are restrained from axial movement along the surface of the crank element 53 by means of cages formed by narrow, inwardly extending, annular extensions 54' of the strap 52.
  • the extensions 54 are located adjacent the ends of the bearing elements 54.
  • Strap 52 may be provided with axially extending lugs 52' which permit the strap 52 totilt without binding.
  • the lugs- 52' are arranged to cooperate with the adjacent side surfaces of the flanges 55 and 56. of the crank 51 to prevent binding of the strap due to excessive axial movement thereof.
  • the clearance between the side faces of the lugs and the respective faces of the cooperating flanges might be, for example, about .003 inch to .010 inch.
  • one form of the invention involves the provision of reliefs or cut-out portions in the crank element 53' to prevent or minimize the binding and/or'burning which occurs due to the misalignment.
  • the reliefs are provided to permit relative angular displacement or relative twisting movement of the pitman, crank element and needle bearing whereby the upper end of the pitman may follow the arcuate' path imparted thereto without causing a corresponding burning or binding of the strap 52, needles 54 and crank element 53.
  • the reliefs effectively provide flexibility in the driving connections by permitting the pitman to tilt the needle or roller bearings relative to the crank element. It should be observed that similar burning and binding occurs at high operating speeds when the lower end of the pitman is coupled to the crank shaft through a ball crank arrangement as shown in the aforementioned Peterson et al. patent.
  • Thev location of. the reliefs on. the crank element is dependent upon'tlie loading of this element.
  • the reliefs are located. to be effective in providingfiexibility-when. bearing loading is at aminimum. With this preferred location of the reliefs, little. or none of the bearingaarea; used. at high load positions is removed.
  • the force of needle penetration is usually neglitends to cause excessive wear and mam gible so that the bearings are almost entirely inertia loaded. Accordingly, in the sewing machine of Fig. 1, the high load conditions correspond to the top and bottom of the needle stroke or, in other words, the uppermost and lowermost positions of the right hand end of the needle lever 34.
  • the loading will be at a minimum midway between these positions. Therefore, by so correlating the parts that the pitman 37 is substantially vertical at the top and bottom of its stroke, there will be no alignment under maximum load conditions and misalignment is at a maximum at the middle of the stroke where the loading is light.
  • the reliefs are preferably located on the crank element 53 so as to be effective in the middle portion of each stroke of the pitman 37. It will be appreciated that very little movement of the pitman, and hence very little misalignment, takes place during a substantial arc of movement of the crank element at the top and bottom portions of its path. Therefore, the crank element may have portionsof substantial arcuate extent which provide full bearing contact in the regions where maximum load conditions are encountered.
  • crank element 53 may be provided to compensate for misalignment of the pitman 37.
  • Fig. 3 which illustrates the crank 51 with pitman 37 substantially in its uppermost position
  • two reliefs 60 and 61 are provided on the front side of the crank element 53.
  • Reliefs 60 and 61 are located on opposite sides of a plane passing through the center of crank element 53 and perpendicular to the axis of shaft 50.
  • Two similar reliefs 62 and 63 (Fig. 4) are provided on the back side of crank element 53.
  • the diagonally disposed reliefs 60 and 63 cooperate to overcome burning and binding during a major portion of either the up or the downstroke of pitman.37, depending on the direction of rotation of shaft 50.
  • Reliefs 61 and 62 cooperate similarly on the other pitman stroke.
  • each relief is dependent on the amount and character of the misalignment to be compensated.
  • the reliefs are semicircular in shape with their diameters adjacent the respective flanges 55 and 56 and with their maximum depths adjacent the extremities of the crank pin.
  • the diameters of the semicircular reliefs in Fig. 3 are somewhat less than the diameter of crank element 53, thus providing a full bearing surface for the maximum load conditions occurring when the pitman 37 is at the top of its stroke and at the bottom thereof.
  • Reliefs 62 and 63 have the same shape and extent as reliefs 60 and 61.
  • crank element 53 with its reliefs is shown in a position corresponding to the uppermost pitman travel in plan view in Fig. 4 and in side elevational view in Fig. 5.
  • the varying radial depths of the reliefs can be clearly seen in Figs. 6 and 7.
  • each relief increases in depth, at any transverse plane, from the circumference of the semicircular outline toward the line which divides the semicircle into quadrants. This provides for maximum tilting of the bearing elements when the misalignment is greatest and the load the smallest.
  • the maximum amount of misalignment which can be compensated is dependent on the maximum depth and extent of the reliefs. The latter are, in turn, limited by the requirement that there be sufficient bearing area in the maximum load position.
  • the relative location of the parts determines where the reliefs should be located.
  • Pitman 37 and the related parts may be arranged to place the pitman in vertical position at any portion of its stroke, preferably coinciding with maximum load conditions for the parts being operated, and the reliefs would then need to be located correspondingly.
  • the modified arrangement comprises a crankshaft 70 and a crank 71.
  • the crank 71 comprises a pair of crank arms 72 and 73 having flanges 74 and 75, respectively, between which extends a crank element 76.
  • the crank element 76 is provided with two reliefs 77 and 78 which extend circumferentially about 300 degrees at each end of the crank element.
  • the circumferential extent of the reliefs at the ends or" the crank element preferably lies within the range of about 270 to 360.
  • the maximum relief is provided at the ends of the crank element, the circumferential extent thereof decreasing on a curve to-provide a 360 bearing area of suitable width at the center of the crank element.
  • the reliefs 77 and 78 extend from points near the central transverse plane through the crank element to the respective ends of the crank element and increase in radial depth from such central plane outward, as shown best in Figs. 10 and 11. It will be observed that a small circumferential portion 79 of the crank element adjacent the center thereof remains at full diameter to take the load at points other than that corresponding to maximum load. Furthermore, a small axially extending portion 80 of the crank element is maintained at full diameter for the entire length of the crank element toprovide full line contact with the needle or other bearing means at the times of maximum load conditions.
  • a pitman 90 which may form part of the feed dog driving connections as disclosed in the aforementioned Reimer application, is provided at one end thereof with an annular strap which surrounds an eccentric 91.
  • the eccentric 91 surrounds and snugly fits an inner eccentric 92 carried by a shaft 93.
  • the eccentric 92 is adapted to be turned relative to the shaft 93, while the eccentric 91 turns with the shaft, as explained in the said Reimer application, to vary the eccentricity of the eccentric 91 relative to the axis of shaft.
  • Eccentric 91 is recessed or counterbored as indicated at 94 (Fig.
  • a friction element 100 is interposed between the flanged end of the eccentric 92 and the inner face of the disc 98.
  • a radially extending shoulder 101 adjacent the inner end of the eccentric 91 is arranged to cooperate with a; portion of an inwardly extending flange 102- at the inner end of the collar 97.
  • the relationship between the flange 102, the shoulder 101 and the main body of the collar 97 is such that relative movement in a radial direction may take place between the eccentric 91 and the collar 97 as the eccentric is adjusted. At all times there will be some portion of the flange 102 in engagement with shoulder 101 to resist outward axial movement of the eccentric 91 in relation to the collar 97 under the force of spring 95.
  • a driving connection is provided between the disc 98 and the eccentric 91 so that the latter will rotate at all times with the shaft 93.
  • This connection comprises a pin 103 inserted in an opening in a disc 98 and having an enlarged head operate with a notch formed in the enlarged end or flanged portion of the eccentric 91.
  • the inner surface of the strap 90 is separated from the outer surface of the eccentric 91 by a plurality of closely spaced roller or needle bearing elements 105.
  • the surface of eccentric 91 which cooperates with bearing elements 105 is provided with four reliefs or cut out portions 106, 107, 108 and 109 which have the same general shape and extent as the reliefs shown in Figs. l7.
  • the reliefs are preferably effective at points of minimum load, while full line contact is preferably provided at points of maximum load.
  • the relative positioning of the eccentric 91 and pitman 90 in Fig. 12 corresponds to a minimum load condition, while that in Fig. 13 corresponds to a maximum load condition. If the load conditions were different, the location of the reliefs around the periphery of the eccentric 91 should be changed accordingly.
  • the eccentric 91 may, if desired, be provided with only two reliefs, as described for a crank element in connection with Figs. 8-11. Such a construction is illustrated in Figs. l7, l8 and 19.
  • the eccentric 91 is provided with two reliefs 110 and 111 which have a circumferential extent of about 300 degrees at the ends of the eccentric 91.
  • a portion 112 of eccentric 91 extending axially along the surface thereof for the full width of the eccentric, over an arc of about 60, is maintained at full diameter to provide full line contact with the needle or roller bearings in this area in which maximum load is involved, while a narrow portion 113 of the eccentric 91, extending circumferentially completely around the same is maintained at full diameter to take the loading at other points.
  • the specific linear and. angular dimensions of the various surfaces may be varied considerably, as previously set forth, to suit particular requirements.
  • the depth, taper and extent of the relief provided are dependent on the amount of misalignment to be compensated.
  • the reliefs may be provided on either the crank element (or eccentric) or on the confining strap. In certain applications, it may be desirable to provide reliefs on both the crank element (or eccentric) and on the confining strap.
  • An example of reliefs provided on the strap is illustrated in Figs. 2022.
  • FIG. 20-22 the construction shown is applicable to a flat bed sewing machine of the type shown inFig. 1 and the shaft 50' of Fig. 20 corresponds to the shaft 50 of Fig. l.
  • the shaft 50 is provided with a crank comprising arms 121 and 122 having flanges or cheeks 123 and 124, respectively, between which extends a crank element 125.
  • the crank element 125 differs from the crank element 53' in that it is not provided with reliefs. It is of simple cylindrical form.
  • a pitm'an 37 corresponding to the'pitrnan' 3710f Fig. 1', is provided with a split strap member 126 which provides" an annular 104 provided. with flat sides which coof the type shown in Fig. 1.
  • the bearing surface for the pitman 37' and is operatively connected to the crank element 125 by a plurality of closely' space'd roller or needle bearing elements 127.
  • Strap 126 has its two sections held together by the screw threaded extcnsions of pitman rods 37' in the manner explained in relation to Fig. 2.
  • the bearing elements 127 may be restrained from axial movement along the surface of the crank element 125 by means of a suitable cage.
  • the strap 126 is provided with two reliefs or clearance cuts 129 and 130. These reliefs, which are located on opposite ends of the strap 126, extend throughout respective halves of the circumference of the strap.
  • the relief 129 is shown by the shading on strap 126 in Fig. 22, while the relief 130 is shown by the shading on strap 126 in Fig. 21.
  • a sewing machine comprising stitch forming and Work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable element whereby rotary motion of said shaft member is translated into oscillatory motion of said oscillatable element, said first coupling means comprising an eccentrically disposed driving surface on the shaft member and a bearing surface on said pitman arranged to coact with said driving surface, said portions of the coacting surfaces of said shaft member and said pitman being of truly cylindrical contour and other portions of at least one of said surfaces being relieved toward its ends to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman and otherportions of said coacting surfaces having bearing engagement along a line extending axially of said shaft member for substantially the full axial
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to. said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable element whereby rotary motion of said shaft member is translated into oscillatory motion of said oscillatable element, oscillation of said oscillatable element providing a varying load on said first coupling means, said first coupling means having a bearing surface which is relieved toward its ends in certain diametrically opposed portions of its circumference to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman, other portions of said bearing surface being of cylindrical form over a sufficiently wide area substantially to prevent rocking of said pitman on said shaft member to thereby maintain said pitman substantially perpendicular to the axis of said shaft member during other portions of
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element,-a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable element whereby rotary motion of said shaft member is translated into oscillatory motion of said oscillatable element, oscillation of said oscillatable element providing a load on said first coupling means, said load varying between a maximum value and a minimum value in the course of a cycle of oscillation of said element, said first cou pling means comprising an eccentrically disposed driving surface on the shaft member and a bearing surface on said pitman arranged to coact with said driving surface, certain portions of at least one of said surfaces being relieved to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman and other portions of said coacting
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable elemotion of said shaft member is translated into oscillatory motion of said oscillatable element, said first coupling means comprising a bearing surface which is relieved toward opposite ends thereof at diametrically opposite points in certain regions to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman, said bearing surface having certain diametrically opposed regions not more than one of which is relieved, thereby providing straight line engagement of the cooperating portions of said pitman and bearing surface and thus affording a substantially non-rockable connection between said pitman and said shaft member during other portions of the travel of said pitman.
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable element whereby rotary motion of said shaft member is translated into oscillatory motion of said oscillatable element, oscillation of said oscillatable element providing a varying load on said first coupling means in the course of a cycle of oscillation of said element, said first coupling means comprising an eccentrically disposed driving surface on the shaft member and a bearing surface on said pitman arranged to coact with said driving surface, at least one portion of at least one of said surfaces being relieved so as to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman corresponding to a relatively low load on said first coupling means, at least one other
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable element whereby rotary motion of said shaft member is translated into oscillatory motion of said oscillatable element, said first coupling means comprising a crank arranged to rotate with said shaft member and having a crank element, a strap connected to said pitman and arranged to surround said crank element and a plurality of roller-type bearing elements interposed between said crank element and said strap, said crank element and said strap having bearing surfaces arranged to engage said roller-type bearing elements, portions of at least one of said bearing surfaces being cut away thereby to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman, other portions of said one of said bearing surfaces
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable clement whereby rotary motion of said shaft member is trans lated into oscillatory motion of said oscillatable element, said first coupling means comprising a crank arranged to rotate with said shaft member and having a crank element, a strap connected to' said pitman and arranged to surround said crank element and a plurality of rollertype bearing elements interposed between said crank element and said strap, said crank element and said strap having bearing surfaces arranged to engage said rollertype bearing elements, portions of the bearing surface of said crank element being cut away thereby to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman, other portions of 's
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable element whereby rotary motion of said shaft member is translated into oscillatory motion of said oscillatable element, said first coupling means comprising a crank arranged to rotate with said shaft member and having a crank element, a strap connected to said pitman and arranged to surround said crank element and a plurality of roller-type bearing elements interposed between said crank element and said strap, said crank element and said strap having bearing surfaces arranged to engage said roller-type bearing elements, portions of the bearing surface of said strap being cut away thereby to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetwcen during certain portions of the travel of said pitman, other portions of said strap having
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable element whereby rotary motion of said shaft member is translated into oscillatory motion of said oscillatable element, said first coupling means comprising a crank arranged to rotate with said shaft member and having a crank element, a strap connected to said pitman and arranged to surround said crank element and a plurality ofclosely spaced needle bearing elements interposed between said crank element and said strap, said crank element and said strap having bearing surfaces arranged to engage said needle bearing elements, two portions of the bearing surface of said strap being cut away thereby to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman, other portions of said strap having a true
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one-end of saidpitinan to said shaft member and a second coupling means for connecting the other end of said pitman to said'oscillatable element whereby rotary motion of said'shaft member is translated into oscillatory motion of said oscillatable element, said first coupling means comprising a crank arranged to rotate with said shaft member andhaving a crank element, a strap connected to said pitmanand arranged to surround said crank element and a pluralityof' closely spaced needle bearing elements interposed between said crank element and said strap, said crank element an'd said strap having bearing surfaces arranged to engage said needle bearing elements, four spaced portions of the bearing surface of said crank element being cut away thereby to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable element whereby rotary motion of said shaft member is translated into oscillatory motion of said oscillatable element, said first coupling means comprising a crank arranged to rotate with said shaft member and having a crank element, a strap connected to said pitman and arranged to surround said crank element and a plurality of closely spaced needle bearing elements interposed between said crank element and said strap, said crank element and said strap having bearing surfaces arranged to engage said needle bearing elements, two portions of the bearing surface of said crank element being cut away thereby to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman, other portions of said crank element having a
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable element whereby rotary motion of said shaft member is translated into oscillatory motion of said oscillatable element, said first coupling means comprising an eccentric element arranged to rotate with said shaft member, a strap connected to a said pitman and adapted to surround said eccentric and a plurality of roller-type bearing elements interposed between said eccentric and said strap, said eccentric and said strap each having a bearing surface arranged to en-- gage said roller-type bearing elements, portions of at least i one of said bearing surfaces being cut away thereby to provide a rockable connection between said pitmanand said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman, other portions of said bearing surfaces
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable element whereby rotary motion of said shaft member is translated into oscillatory motion of said oscillatable element, said first coupling means comprising an eccentric element arranged to ro tate with said shaft member, a strap connected to said pitman and adapted to surround said eccentric and a plurality of closely spaced needle bearing elements interposed between said eccentric and said strap, said eccentric and said strap each having a bearing surface arranged to engage said needle bearing elements, four portions of the bearing surface of said 7 eccentric being cut away thereby to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman, other portions of said bearing surface being truly circular in contour
  • a sewing machine comprising stitch forming and work feeding elements and driving connections therefor, said driving connections comprising a shaft member, means to impart rotary motion to said shaft member, an oscillatable element, a pitman, a first coupling means for connecting one end of said pitman to said shaft member and a second coupling means for connecting the other end of said pitman to said oscillatable element whereby rotary motion of said shaft member is translated into oscillatory motion of said oscillatable element, said first coupling means comprising an eccentric element arranged to rotate with said shaft member, a strap connected to said pitman and adapted to surround said eccentric and a plurality of closely spaced needle bearing elements interposed between said eccentric and said strap, said eccentric and said strap each having a bearing surface arranged to engage said needle bearing elements, two portions of the bearing surface of said eccentric being cut away thereby to provide a rockable connection between said pitman and said shaft member to compensate for misalignment therebetween during certain portions of the travel of said pitman, other portions of the bearing surface of said eccentric being of truly circular contour and providing
  • a flat bed sewing machine having a needle bar, a needle lever for reciprocating said needle bar, said needle lever being arranged to rock about a fixed axis, and a main driving shaft, connecting means inter-coupling said main driving shaft and said needle lever whereby turning of the former produces rocking movement of the latter, said connecting means comprising a pitman element,- means for connecting one end of said pitman element to said needle lever, and means for connecting the other end of said pitman element to said shaft, said latter means comprising an eccentrically disposed driving surface on the main driving shaft and a bearing surface on the pitman element arranged to coaet with said driving surface, certain portions of at least one of said coacting surfaces being relieved toward the ends thereof to provide a rockable connection between said pitman and said shaft to compensate for misalignment therebetween during certain portions of the travel of said pitman, other portions of said coacting surfaces having bearing engagement along a straight line extending parallel with the axis of said driving shaft for substantially the full axial length of said eoacting surfaces to
  • connecting means intercoupling said main driving shaft and said needle lever whereby turning of the former produces rocking movement of the latter
  • said connecting means comprising a pitman element, means for connecting one end of said pitman element to said needle lever, and means for connecting the other end of said pitman element to said shaft
  • said latter means comprising a crank arranged to rotate With said shaft and having a crank element, a strap connected to said pitman and adapted to surround said crank element and a plurality of closely spaced roller-type bearing elements interposed between said strap and said crank element, said crank element and said strap each having a bearing surface arranged to engage said roller-type bearing elements; portions of at least one of said bearing surfaces being cut away to provide a rockable connection between said pitman and said crank element to compensate for misalignment therebetween during certain portions of the travel of said pitman, other portions of said bearing surfaces being
  • a fiat bed sewing machine having a needle bar, a needle lever for reciprocating said needle bar, said needle'lever being arranged to rock about a fixed axis, and a main driving shaft, connecting means intercoupling said main driving shaft and said needle lever whereby rotation of the former produces rocking movement of the latter, said connecting means comprising a pitman, means for connecting one end of said pitman to said needle lever, and means for connecting the other end of said pitman-to said shaft, said latter means comprising a crank arranged to'rotate with said shaft and having a crank element, a strap connected to said pitman and adapted to accommodate said crank element and a plurality of closely spaced roller-type bearing elements intcrposed between said strap and said crank element, said crankrelement and said strap each having a bearing surface arranged to engage said roller-type bearing elements, portions of the bearing surface of said crank element being cutaway to provide a rockable connection between said pitman and said crank element to compensate for misalignment therebetween during certain portions of the travel of said pitman
  • a fiat bed sewing machine having a needle bar, a needle lever for reciprocating said needle bar, said needle lever being arranged to rock about a fixed axis, and a main driving shaft, connecting means inter-coupling said rnain driving shaft and said needle lever whereby rotation of the former produces rocking movement of the latter
  • said connecting means comprising a pitman, means for connecting one end of said pitman to said needle lever, and means for connecting the other end of said pitman to said shaft
  • said latter means comprising a crank arranged to rotate with said shaft and having a crank element, a strap connected to said pitman and adapted to surround said crank element and a plurality of closely spaced roller-type bearing elements arranged operativcly to connect said strap and said crank element, said crank element and said strap each having a bearing surface arranged to engage said roller-type bearing elements, portions of the bearing surface of said strap being cut away to provide a rockable connection between said pitman and said shaft to compensate for misalignment therebetween during first selected portions of the travel of said pit
  • a' flat bed sewing machine having a needle bar, a needle lever for reciprocating said needle bar, said needle lever being arranged to rock about a fixed axis, and a main driving shaft, connecting means inter-coupling said main driving shaft and said needle lever whereby rotation of the former produces rocking movement of the latter
  • said connecting means including a pitman comprising a pair of substantially parallel generally vertical rods disposed on respective sides of said shaft and of said needle lever, means for connecting one end of each of said rods to said needle lever, and means for connecting the other end of each of said rods to said shaft
  • said latter means comprising a crank arranged to rotate with said shaft and having a crank element, a strap connected to said other ends of said rods and adapted to surround said crank element and a plurality of closely spaced rollertype bearing elements arranged operatively to connect said strap and said crank element, said crank element and said strap each having a bearing surface arranged to engage said roller-type bearing elements, portions of at least one of said bearing surfaces being cut away to provide a rockable

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Textile Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Sewing Machines And Sewing (AREA)
US310295A 1952-09-18 1952-09-18 Sewing machine bearing and pitman construction Expired - Lifetime US2729179A (en)

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Application Number Priority Date Filing Date Title
US310295A US2729179A (en) 1952-09-18 1952-09-18 Sewing machine bearing and pitman construction
FR1080957D FR1080957A (fr) 1952-09-18 1953-06-23 Mécanisme à bielle ou à barre d'excentrique pour machines à coudre
DEU2381A DE953482C (de) 1952-09-18 1953-09-04 Naehmaschine mit Kurbel- oder Exzenterantrieb der Nadelstangenschwingwelle von der Hauptantriebswelle aus
GB25675/53A GB726638A (en) 1952-09-18 1953-09-17 Improvements in or relating to sewing machines

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2903986A (en) * 1957-03-25 1959-09-15 Singer Mfg Co Trimming mechanisms for sewing machines
US2928698A (en) * 1954-10-19 1960-03-15 Feighofen Hans Two-ring rotary bearing
US6647907B1 (en) * 2002-05-22 2003-11-18 George Long Chain stitch machine
US10663033B2 (en) 2017-07-12 2020-05-26 American Axle & Manufacturing, Inc. Balance shaft having reduced mass and inertia

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US785617A (en) * 1903-12-10 1905-03-21 Differential Ore Crushing Machine Company Ltd Stone-crusher.
DE323811C (de) * 1918-08-29 1920-08-07 Demag Drucklufttech Kugellager mit mehreren Kugelbahnen
FR571061A (fr) * 1922-09-16 1924-05-12 Schneider & Cie Montage à rouleaux pour paliers de têtes de bielles et vilebrequins de moteurs à explosions
DE426999C (de) * 1925-04-02 1926-08-30 H C G Dettmar Dr Ing Gleitlager
US2239834A (en) * 1939-12-12 1941-04-29 Williams Judson Bearing
US2446342A (en) * 1946-06-28 1948-08-03 Union Special Machine Co Sewing machine
US2662495A (en) * 1950-10-05 1953-12-15 Singer Mfg Co Needle-bar drive for zig-zag sewing machines

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE858341C (de) * 1951-01-21 1952-12-04 Star Kugelhalter Ges M B H Deu Waelzlageranordnung, insbesondere fuer Zugstangen fuer Naehmaschinen

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US785617A (en) * 1903-12-10 1905-03-21 Differential Ore Crushing Machine Company Ltd Stone-crusher.
DE323811C (de) * 1918-08-29 1920-08-07 Demag Drucklufttech Kugellager mit mehreren Kugelbahnen
FR571061A (fr) * 1922-09-16 1924-05-12 Schneider & Cie Montage à rouleaux pour paliers de têtes de bielles et vilebrequins de moteurs à explosions
DE426999C (de) * 1925-04-02 1926-08-30 H C G Dettmar Dr Ing Gleitlager
US2239834A (en) * 1939-12-12 1941-04-29 Williams Judson Bearing
US2446342A (en) * 1946-06-28 1948-08-03 Union Special Machine Co Sewing machine
US2662495A (en) * 1950-10-05 1953-12-15 Singer Mfg Co Needle-bar drive for zig-zag sewing machines

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2928698A (en) * 1954-10-19 1960-03-15 Feighofen Hans Two-ring rotary bearing
US2903986A (en) * 1957-03-25 1959-09-15 Singer Mfg Co Trimming mechanisms for sewing machines
US6647907B1 (en) * 2002-05-22 2003-11-18 George Long Chain stitch machine
US10663033B2 (en) 2017-07-12 2020-05-26 American Axle & Manufacturing, Inc. Balance shaft having reduced mass and inertia
US10816059B2 (en) 2017-07-12 2020-10-27 American Axle & Manufacturing, Inc. Balance shaft having reduced mass and inertia

Also Published As

Publication number Publication date
DE953482C (de) 1956-11-29
GB726638A (en) 1955-03-23
FR1080957A (fr) 1954-12-15

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