Safety brake for block and tackle window balance

A block and tackle window balance system comprising:

• a track;
• a translatable block assembly moveably disposed at least partially within the track;
• a balance spring having a first end fixed relative to the track and a second end coupled to one end of the translatable block assembly;
• a cord comprising a first cord end and a second cord end, wherein the first cord end is attached to an opposite end of the translatable block assembly and the second cord end is attached to a jamb when installed in a window;
• and
• a brake coupled to the translatable block assembly, wherein the brake activates in response to a rapid acceleration of the translatable block assembly along the track.

An inertial braking system for a block and tackle window balance device comprising:

• a track;
• a translatable block assembly defining a pocket and moveably disposed at least partially within the track;
• and
• a brake coupled to the translatable block assembly and disposable within the pocket, wherein the brake activates in response to a rapid acceleration of the translatable block assembly along the track, wherein the brake comprises a pawl pivotably coupled to the translatable block assembly, wherein the pawl pivots to engage the track in response to the rapid acceleration of the translatable block assembly along the track, and wherein the pawl comprises:
• an arcuate surface having a first end and a second end circumferentially disposed relative to a pivot point of the pawl;
• a first radial distance defined from the pivot point to the first end of the arcuate surface;
• and
• a second radial distance defined from the pivot point to the second end of the arcuate surface, wherein the second radial distance is greater than the first radial distance.

A method of inhibiting rapid acceleration of a component of a block and tackle window balance system, the method comprising the steps of:

• providing a track;
• providing a translatable block assembly movably disposed at least partially within the track;
• providing a brake, the brake comprising a pawl and a cam, the pawl and the cam each pivotally coupled to the translatable block assembly, the cam in communication with a brake shoe;
• and
• activating the brake in response to a rapid acceleration of the translatable block assembly in a first direction along the track.