Patent GB-1095530-A (GB)
IPC: D05B51/00
Abstract: 1,095,530. Sewing machines. SINGER CO. Nov. 29, 1966 [Dec. 13, 1965], No. 53289/66. Heading D1G. In a sewing machine comprising a worksupporting bed and an overhanging bracket arm terminating in a head, a unitary assembly removably mounted in the head for movement towards and away from the bed is provided with a thread-carrying needle, a thread supply for the needle, and means for directing the thread from the supply to the needle, the unitary assembly being actuated to co-operate with a looptaker mounted in the bed for concatenating needle thread loops. The upper arm 16 journals an axially-slidable shaft 20 which carries a handwheel 38 and is formed with an axial groove 36 slidably receiving a key 34 rigid with an eccentric sheave 30 mounted on shaft 20. A worm wheel 28 on sheave 30 meshes with a worm 26 on the shaft 24 of a motor 22 mounted in the standard 14. Motor 22 is controlled by moving a lever 35 to shift a pin 37 into and out of engagement with switch contacts. Shaft 20 is biased inwardly by a spring 48. Arm 16 ends in a head 18 housing a removable unitary assembly 46 comprising a hollow needle bar 132 rigid at its lower end with a hollow needle 168 and at its upper end with a hollow cylindrical casing 130. An end wall of the latter is formed with a groove 156 normally engaged by a crank pin 44 on shaft 20 for reciprocating assembly 46. Such end wall carries a pin 142 supporting a hub 150 on a transparent flange 146 closing the open end of casing 130. Hub 150 journals a bobbin 136, thread from which passes through the needle bar to the needle. Bobbin 136 is braked by a leaf spring 144 for tensioning the thread. Head 18 is formed with an aperture 161 for viewing the amount of thread remaining on a bobbin. For removing assembly 46, wheel 38 is rotated to position crank pin 44 in its uppermost position, and is then drawn outwardly to disengage pin 44 from groove 156. Assembly 46 may then be withdrawn through an aperture 19 in head 18 by means of a finger grip 160 thereon. A new assembly may then be inserted and wheel 38 released for reengaging pin 44 with groove 156. The presser foot 114 is rigid with a downwardly spring- biased sleeve 118, which supports the needle bar and is supported in an extension 120 of head 18. A finger 126, rigid with sleeve 118, co-acts with a rotary cam surface 124 for raising the presser foot. Eccentric 30 actuates a pitman 82, the lower end of which is formed with a slot 84 embracing a fixed shaft 70. A link 76 connects pitman 82 to one corner of a triangular lever 66, the second corner being falcrummed on shaft 70, and the third corner being connected by a link 60 to a crank pin 58 on a shaft 54, journalled in the free standing bed 12, for oscillating shaft 54. A cylindrical block 50, fixed eccentrically to shaft 54, carries a looper finger 52 for cooperation with needle 168. A feed dog 102, formed with a looper-receiving slot 103, is slidable on a pin 106 carried by a plate 108 biased upwardly by a leaf spring 112. Feed dog 102 is biased towards one end position by a spring 110, and rests on eccentric 50 for receiving vertical movements. A bar 86 is formed at one end with a structure 88 which is pivoted on a fixed pin 90 and carries a pin 94 pivoted in a block 96 slidable in slot 84. The other end of bar 84 is formed with a finger 100 engaged in a notch 101 in feed dog 102 for imparting horizontal movements thereto. The front of the machine is enclosed by a removable plastics cover (49). Bed 12 is supported by a pair of arms 17 pivoted thereto.