Crossbows - Spanning Methods
Hand spanned crossbows were initially the norm, but as the power of crossbows increased, human ingenuity came up with all manner of devices to span these more powerful crossbows.
From around 1200 onward devices were invented to help span more and more powerful bows for the military and moneyed classes.
The principle ones are shown here.
Single or double hook spanning belt
A strong belt is worn around the waist onto which a double or single hook it attached using a strap.
The archer squats slightly, hooks the string and stands to span the bow.
DATES: 1200 onward
MECHANICAL ADVANTAGE: 1:1, but uses trunk muscles as well as leg muscles
POUNDAGE SPANNED: 300lbs maximum
Spanning Belt with Doubler Pulley
A strong belt is worn around the waist onto which a pulley is fitted; this can be done using ropes or leather straps.
The archer squats slightly, hooks the device onto the string and crossbow and stands to span the bow.
DATES: 1250 onward
MECHANICAL ADVANTAGE: 2:1, but uses trunk muscles as well as leg muscles
POUNDAGE SPANNED: 450lbs maximum
Goats Foot Lever
A lever is placed on the bow that hooks onto the string and is pulled back to span the crossbow.
Once the string is drawn back, the lever is removed.
DATES: 1300 onward
MECHANICAL ADVANTAGE: constantly changes during the lever movement and dependent on lever design, but up to 30:1
POUNDAGE SPANNED: 500lbs maximum
Gaffe lever
A lever is hooked on the front of the crossbow which pushes the string back to the nut to span it.
Once the string is drawn back, the lever is removed.
DATES: 1500 onward
MECHANICAL ADVANTAGE: constantly changes during the lever movement and dependent on lever design, but up to 30:1
POUNDAGE SPANNED: 400lbs maximum
Windlass
The archer attaches the mechanism onto the crossbow and rotates the handles to span the bow.
Once loaded the windlass is removed.
DATES: 1400 onward
MECHANICAL ADVANTAGE: constant advantage through each rotation, but around 160:1 (from hand grips)
POUNDAGE SPANNED: 1250lbs maximum
15thC and 16thC Cranequin
The cranequin is slipped over the stock of the bow and the hooks on the rack are latched onto the string.
The crank handle is then rotated to span the crossbow and once spanned, the cranequin is removed.
DATES: 1400 onward
MECHANICAL ADVANTAGE: constant advantage through each rotation, but around 600:1 (from hand grip)
POUNDAGE SPANNED: 1200lb maximum
16thC and 17thC Cranequin
The cranequin is slipped over the stock of the bow and the hooks on the rack are latched onto the string.
The crank handle is then rotated to span the crossbow and once spanned, the cranequin is removed.
DATES: 1500 onward
MECHANICAL ADVANTAGE: constant advantage through each rotation, but around 840:1(from hand grip)
POUNDAGE SPANNED: 1200lb maximum
Lever Action
An inbuilt lever which houses the trigger is rotated forward to catch the string and pulled back to span the crossbow.
DATES: 1560 onward
MECHANICAL ADVANTAGE: constantly changes during the lever movement and dependent on lever design, but up to 25:1
POUNDAGE SPANNED: 300lb maximum
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