Sewing Machine Feed Dog Drive Mechanism for Compact Size
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Solution Overview
Problem
The existing sewing machine feed dog drive devices require a complex configuration and large space due to the vertical drive unit with a feed dog operation clutch, making it difficult to achieve a compact size for the sewing machine.
Innovation Solution
A simplified feed dog drive device configuration using an eccentric cam, advance and retreat arm, raising and lowering link, and a guide member pivot mechanism, which allows the feed dog to project and retract from the throat plate while maintaining a compact vertical drive unit, enabling efficient fabric feeding without fabric interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a feed dog operation clutch is added to block vertical motion of the feed dog, then fabric sticking is prevented, but device complexity and space requirements increase
Solution Approach 1:
The invention extracts the feed dog operation clutch from the vertical drive unit, separating its function into an independent component. The clutch is positioned separately to engage with the feed dog's lateral movement mechanism rather than being integrated into the vertical drive, thereby preventing fabric sticking while simplifying the vertical drive unit's configuration and reducing its space requirements.
Solution Approach 2:
The feed dog operation clutch acts as an intermediary component that mediates between the lateral feed drive unit and the feed dog. It selectively blocks or transmits lateral motion to the feed dog based on the sewing cycle phase, preventing fabric sticking during needle positioning without interfering with the vertical drive unit's operation.
2Object-affected harmful factors
If the feed dog operation clutch is integrated into the vertical drive unit, then fabric sticking is prevented, but the space required below the throat plate increases
Solution Approach 1:
The invention segments the feed dog control system into separate functional components: the vertical drive unit for vertical motion, the lateral feed drive unit for lateral motion, and the feed dog operation clutch for motion control. By positioning the clutch separately and having it engage with the lateral feed mechanism rather than being integrated into the vertical drive unit, the space required below the throat plate is significantly reduced while maintaining the function of preventing fabric sticking.
3Object-affected harmful factors
If the feed dog is made to retract below the throat plate during needle positioning, then fabric sticking is prevented, but additional control mechanisms are required
Solution Approach 1:
The invention merges the feed dog operation clutch with the lateral feed drive unit's existing components. The clutch utilizes the lateral feed connecting rod and feed dog's lateral movement mechanism to achieve the blocking function, rather than requiring a separate actuation system. This integration prevents fabric sticking while minimizing additional complexity in the feed dog drive device.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for a reduced sewing machine size while ensuring smooth sewing preparations and preventing fabric sticking to the feed dog, achieving efficient fabric feeding and compactness.
Implementation Method 1
a vertical drive unit configured to convert rotation of the drive shaft into vertical motion and transmit the vertical motion to the feed dog, wherein the vertical drive unit includes an eccentric cam configured to be rotated by the drive shaft
Implementation Method 2
a raising and lowering link having a lower end connected to the advance and retreat arm via a lower-part connecting shaft, and an upper end connected to the feed base via an upper-part connecting shaft
Data Source
AI summary
Provided is a sewing machine that can be reduced in size by employing a simple configuration for a feed dog drive device. A lateral feed drive unit (8) and a vertical drive unit (9) transmit rotation of a drive shaft (7) to a feed dog (3). The feed dog (3) is supported by a swingable feed base (5). A square piece (18) is provided at a lower end of a raising and lowering link (15) of the vertical drive unit (9). A guide member (19) including a guide groove (20) configured to guide the square piece (18) is disposed right under the feed base (5). An upper end of the raising and lowering link (15) is connected to a part of the feed base (5) between the swinging shaft (6) and the feed dog (3).