Antique Bronze or Brass Spring Loaded Cleat Rope Clamp Mystery Tool Nice Patina

Offered here, this interesting solid bronze or brass device with an unknown (at least to me) function. I haven't been able to find another one on line and would love to know what this item is used for. The item is generally in good antique condition and the spring is strong but it has lost most of the black finish and has age associated minor surface imperfections, scuffs scratches and dings. Measures overall approximately 4-3/4" (12cm) long x 1-1/4" (3cm) wide x 1-5/8" (4cm) tall. Returns accepted within 3 days of receipt/inspection if not as described. Thanks