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A sewing machine thus electrified now fit entirely inside a woman-portable carrying case. Electric motors became so common that Singer made provision for them: the model 127/128 'modernized' versions included mounting lugs for a motor, whereas earlier models had to be drilled and tapped.
A sewing machine presser foot. A presser foot is an attachment used with sewing machines to hold fabric flat as it is fed through the machine and stitched. Sewing machines have feed dogs in the bed of the machine to provide traction and move the fabric as it is fed through the machine, while the sewer provides extra support for the fabric by guiding it with one hand.
Trade card, ca 1900. The White Sewing Machine was the first sewing machine from the White Sewing Machine Company. [1] It used a vibrating shuttle bobbin driver design. For that reason, and to differentiate it from the later White Family Rotary that used a rotary hook design instead, it came to be known as the "White Vibrating Shuttle" or "White VS".
Load fluctuations are shock-absorbed (cushioned). They need no lubrication and minimal maintenance. They have high efficiency (90–98%, usually 95%), high tolerance for misalignment, and are of relatively low cost if the shafts are far apart. Clutch action can be achieved by shifting the belt to a free turning pulley or by releasing belt tension.
Multi-jackbolt tensioners (MJTs), registered under the trademark Superbolt or Supernut, are designed to decrease the torque required to tighten large bolted joints. One of the major problems associated with traditional bolt tightening methods is as the diameter of the bolt increases, the amount of torque required to tighten it increases in the third power of the diameter. [1]
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Aside from the belt/chain itself, also common is a failure of the tensioner, and/or the various gear and idler bearings, causing the belt/chain to derail. Furthermore, in engines where the timing belt drives the water pump, failure of the water pump can cause the pump to seize, which can break the timing belt or chain.
Some machines (such as a sewing machine motor) require partial or variable power. In the past, control (such as in a sewing machine's foot pedal) was implemented by use of a rheostat connected in series with the motor to adjust the amount of current flowing through the motor. It was an inefficient scheme, as this also wasted power as heat in ...