Abstract: A thread checking device is installed in combination with a sewing machine in order to exert a proper tension on the thread loop formed at the eye of the needle when the thread loop passes through betweeen the bobbin case and the rotation stopping member for restraining rotation of the bobbin case. This thread checking device is provided with thread suspending means which comprises a thread suspending part disposed near a specified position where the thread guide of the thread take-up member is located when the needle thread loop passes between the bobbin case and the rotation stopping member. The thread suspending means suspends the needle thread held on the thread guide with the suspending part when the take-up member moves from the maximum thread take-up position to the maximum thread slack position.

Abstract: A combination of block units comprising: a generally H-shaped block unit having a configuration including two symmetrical grooves extending in Y-axis direction in a basic rectangular parallel-piped having X-, Y- and Z-axes intersecting with the right angle with each other, each of the grooves has a base wall which is parallel with X-axis and oppositely inclining side walls intersecting with the base wall with an acute angle, the distance between the centerlines extending in the Y-axis direction on the side walls being half of the length of the parallel-piped in the X-axis direction, a generally T-shaped block unit having a configuration attained by bisecting the H-shaped block unit along the X- and Z-axes thereof, a generally U-shaped block unit having a configuration attained by bisecting the H-shaped block unit along the X- and Y-axes thereof, and a generally T-shaped block unit having a configuration complementary to the U-shaped block unit.