System for tracking lifting events at a construction site

1. A system for tracking lifting events at a construction site comprising:

a chassis:

configured to couple to a crane block of a crane at a construction site; and

located over a set of sheaves and side plates of the crane block;

a first idler assembly comprising:

a first cable idler;

a first idler arm:

supporting the first cable idler on a first side of the chassis; and

biasing the first cable idler inwardly toward a first cable loop coupled to a first sheave in the set of sheaves of the crane block; and

a first position sensor coupled to the first idler arm;

a second idler assembly comprising:

a second cable idler;

a second idler arm:

supporting the second cable idler on a second side of the chassis; and

biasing the second cable idler inwardly toward a second cable loop coupled to a second sheave in the set of sheaves of the crane block; and

a second position sensor coupled to the second idler arm; and

a controller configured to, during a lift event:

read a first set of position values from the first position sensor;

read a second set of position values from the second position sensor;

derive a frequency profile of a load carried by the crane block based on the first set of position values and the second set of position values;

derive a weight of the load carried by the crane block based on the first set of position values and the second set of position values;

interpret a load type, from a set of load types, of the load carried by the crane block based on the weight of the load and the frequency profile; and

generate a lift event record specifying the load type and the weight of the load carried by the crane block.

2. The system of claim 1 , wherein the controller is configured to, during the lift event:

read a first time series of position values from the first sensor and a second time series of position values from the second position sensor representing absence of the load carried by the crane block;

derive a natural frequency for the crane block based on the first timeseries of position values and the second timeseries of position values; and

generate an unloaded frequency profile for the crane block based on the natural frequency for the crane block;

read a third time series of position values from the first position sensor and a fourth time series of position values from the second position sensor representing presence of the load at the crane block of the particular load type;

derive a first frequency profile for the load of a particular load type based on the third timeseries of position values, the fourth timeseries of position values and the unloaded frequency profile; and

store the first frequency profile in a set of frequency profiles representing frequency profiles of load types, in the set of load types, carried by the crane block during lifting events.

3. The system of claim 1 , wherein the controller is configured to, during the lift event:

access a first set of baseline tare distance values between the first cable idler and the second cable idler;

calculate a first set of distance values between the first cable idler and the second cable idler based on the first set of position values and the second set of position values;

calculate a distance change between the first set of distance values and the first set of baseline tare distance values; and

derive the weight of the load carried by the crane block based on the distance change.

4. The system of claim 1 , wherein the controller is configured to, during loading of the crane block:

read a first time series of position values from the first sensor and a second time series of position values from the second position sensor representing engagement of the load at the crane block;

derive a set of distances based on a difference between the first time series of position values and the second time series of position values;

interpret the load type, from the set of load types, for the load engaged by the crane block based on the set of distances; and

associate the set of distances with the load type, in the set of load types, interpreted for the load.

5. The system of claim 1 , wherein the controller is configured to, during unloading of the crane block:

read a first time series of position values from the first sensor and a second time series of position values from the second position sensor representing disengagement of the load at the crane block;

derive a set of distances based on a difference between the first time series of position values and the second time series of position values;

interpret the load type, from the set of load types, for the load disengaged by the crane block based on the set of distances; and

associate the set of distances with the load type, in the set of load types, interpreted for the load.

6. The system of claim 1 :

further comprising a motion sensor coupled to the chassis; and

wherein the controller is configured to, during the lift event:

read a set of motion values from the motion sensor; and

derive a load type, from a set of load types, for the load carried by the crane based on the first set of motion values.

7. The system of claim 1 , wherein the controller is configured to, during the lift event:

derive a frequency profile for the load carried by the crane block based on the first set of position values and the second set of position values;

calculate a first weight range of the load based on the frequency profile for the load; and

calculate the weight of the load, within the first weight range based on the first set of position values from the first position sensor and the second set of position values from the second position sensor.

8. The system of claim 1 :

wherein the first idler arm is pivotably coupled to the first side of the chassis;

wherein the first position sensor comprises a rotary encoder configured to output changes in angular position of the first idler arm on the chassis corresponding to changes in a transverse position of the first cable idler on the chassis resulting from changes in weight carried by the crane block; and

wherein the controller is configured to, during the lift event:

access a baseline angular position value for the rotary encoder representing absence of a load carried by the crane block;

read a first angular position value from the rotary encoder of the first position sensor;

calculate a difference between the baseline angular position value and the first angular position value; and

predict the weight of the load carried by the crane block based on the difference.

9. The system of claim 1 , wherein the first cable idler defines:

a first pulley configured to ride along the first cable and mounted to the first idler arm;

a first idler diameter greater than a diameter of the first cable configured to increase an area of contact between the first cable and the first cable idler; and

a first groove of a first groove diameter matching the diameter of the first cable configured to maintain contact with a first region of the first cable loop; and

wherein the first idler assembly further comprises a first spring configured to bias the first cable idler toward the first cable loop.

10. The system of claim 1 , wherein the controller is configured to, during the lift event:

read a set of distances between the first set of position values from the first position sensor and the second set of position values from the second position sensors;

access a baseline tare position value representing the absence of the load;

interpret an anomaly event at the construction site based on change in a difference between the set of distances and the baseline tare position that exceeds a threshold rate of change;

generate a failure condition prompt to cease crane operation based on the anomaly event; and

serve the prompt to an operator via a computing device accessible by the operator.

11. The system of claim 1 :

further comprising a center pin:

arranged within the crane block and defining a load capacity for the crane block;

defining a sheave interface for the set of sheaves of the crane block; and

comprising a force sensor configured to output load values corresponding to forces carried by the center pin; and

wherein the controller is configured to, during the lift event:

read a first time series of load values from the force sensor;

detect a peak load in the first time series of load values; and

predict the weight of the load carried by the crane block based on a combination of the peak load in the first time series of load values, the first set of position values from the first position sensor, and the second set of position values from the second position sensor.

12. The system of claim 1 , wherein the first cable idler defines a groove:

of a diameter matched to a diameter of the cable; and

configured to:

maintain continuous contact with peaks of multiple wires in the first cable loop, the first cable loop comprising a first twisted steel rope; and

prevent the first cable idler from skipping across individual wires in the first twisted steel rope.

13. The system of claim 1 :

wherein the first cable idler is biased to contact a first region of the first cable loop entering the first sheave;

wherein the second cable idler is biased to contact a second region of the second cable loop exiting the second sheave and opposing the first region of the first cable loop; and

wherein the controller is configured to:

read the first set of position values from the first position sensor;

read the second set of position values from the second position sensor;

derive weight at a doubled force resolution based on the first set of position values and the second set of position values.

14. A system for tracking lifting events at a construction site comprising:

a chassis:

configured to couple to a crane block of a crane at a construction site; and

located over a set of sheaves and side plates of the crane block;

a first idler assembly comprising:

a first cable idler;

a first idler arm:

supporting the first cable idler on a first side of the chassis; and

biasing the first cable idler inwardly toward a first cable loop coupled to a first sheave in the set of sheaves of the crane block; and

a first position sensor coupled to the first idler arm;

a second idler assembly comprising:

a second cable idler;

a second idler arm:

supporting the second cable idler on a second side of the chassis; and

biasing the second cable idler inwardly toward a second cable loop coupled to a second sheave in the set of sheaves of the crane block; and

a second position sensor coupled to the second idler arm; and

a controller configured to, during a lift event:

read a first set of position values from the first position sensor;

read a second set of position values from the second position sensor;

derive a frequency profile of the load carried by the crane block based on the first set of position values and the second set of position values;

derive a weight of the load carried by the crane block based on the first set of position values and the second set of position values;

interpret a load type, from a set of load types, of the load carried by the crane based on the frequency profile of the load and the weight of the load; and

generate a lift event record specifying the load type and the weight of the load carried by the crane block.

15. The system of claim 14 , wherein the controller is configured to, during loading of the crane block:

read a first time series of position values from the first sensor and a second time series of position values from the second position sensor representing engagement of the load at the crane block;

derive a set of distances based on a difference between the first time series of position values and the second time series of position values;

interpret the load type, from the set of load types, for the load engaged by the crane block based on the set of distances; and

associate the set of distances with the load type, in the set of load types, interpreted for the load.

16. The system of claim 14 , wherein the controller is configured to:

access a first set of baseline tare distance values between the first cable idler and the second cable idler;

calculate a first set of distance values between the first cable idler and the second cable idler based on the first set of position values and the second set of position values;

calculate a distance change between the first set of distance values and the first set of baseline tare distance values; and

derive the weight of the load carried by the crane block based on the distance change.

17. The system of claim 14 :

further comprising:

a first force sensor coupled to the first idler arm and configured to detect a first force carried from the first idler arm into the first side of the chassis; and

a second force sensor coupled to the second idler arm and configured to detect a second force carried from the second idler arm into the second side of the chassis; and

wherein the controller is configured to, during the lifting event:

read a first force value from the first force sensor;

read a second force value from the second force sensor;

calculate a force average of the first force value and the second force value;

calculate a force difference between the force average and a baseline force value for the load carried by the crane block; and

access a first force function for converting the force difference to weight; and

calculate the weight of the load carried by the crane block based on the force function for the force difference.

18. A system for tracking lifting events at a construction site comprising:

a chassis;

a set of cable loops comprising:

the first cable loop; and

the second cable loop;

a first idler assembly comprising:

a first cable idler;

a first idler arm:

supporting the first cable idler on a first side of the chassis; and

biasing the first cable idler inwardly toward the first cable loop; and

a first position sensor coupled to the first idler arm;

a second idler assembly comprising:

a second cable idler;

a second idler arm:

supporting the second cable idler on a second side of the chassis; and

biasing the second cable idler inwardly toward the second cable loop; and

a second position sensor coupled to the second idler arm; and

a controller configured to, during a lift event:

read a first set of position values from the first position sensor;

read a second set of position values from the second position sensor;

derive a weight of the load carried by the set of cable loops based on the first set of position values and the second set of position values;

derive a frequency profile of the load carried by the set of cable loops based on the first set of position values and the second set of position values;

interpret a load type, from a set of load types, of the load carried by the set of cable loops based on the weight of the load and the frequency profile; and

generate a lift event record specifying the load type and the weight of the load carried by the set of cable loops.

19. The system of claim 18 :

further comprising:

a crane block of a crane at a construction site;

a set of sheaves; and

a set of side plates of the crane block;

wherein the chassis is:

configured to couple to the crane block of the crane at a construction site; and

located over the set of sheaves and the set of side plates of the crane block.

20. The system of claim 18 :

further comprising an optical sensor;

coupled to the chassis; and

defining a field of view facing downward below the set of cable loops; and

wherein the controller is configured to, during the lift event:

access a first image depicting a load carried by the set of cable loops from the optical sensor;

detect the load in a first region of the first image;

extract a first set of features from the first region of the first image; and

interpret the load type, from the set of load types, for the load carried by the set of cable loops based on:

the first set of position values

the second set of position values; and

the first set of features extracted from the first image.