Supply control rotating stretch wrapping apparatus and process

An apparatus for wrapping a film web around a load with a cross-section which causes variations in demand rate for the film web during wrapping, comprising:

• a frame;
• dispenser means mounted on the frame for revolving around the load, for dispensing the film web, and having elongation means for elongating the film web;
• and
• supply speed control means coupled to the elongation means through a mechansim other than the film web for increasing and decreasing the dispensing speed of the elongation means, said supply speed control means comprising means defining a predetermied model substantially approximating the cross-sectional configuration of the load for controlling the speed of said elongation in response to input from said load model, said input being independent of both actual sensed variations in the tension of the film web and actual sensed variations in the demand rate for the film web downstream of the elongation means, said supply control means dispensing the film web from the elongation means at a controlled variable supply speed accoarding to said load model input independent of the sensed variations in the tension of the film web and sensed variations in the demand rate for the film web downstream of the elongation means.

An apparatus for wrapping a film web around a load with a cross-section which causes variations in demand rate for the film web during wrapping, comprising:

• a frame;
• dispenser means mounted on the frame for revolving around the load, and having at least one feeding roller for dispensing film web;
• and
• supply speed control means rotatbly coupled to the roller through a mechanism other than the film web for increasing and decreasing the rotation speed of the roller, said supply speed control means comprising means defining a predetermined model substantially approximating the cross-sectional configuration of the load for rotatably controlling the speed of the roller in response to input from said load model, said input independent of actual sensed variations in the tension of the film web and actual sensed variations in the demand rate for the film web downstream of the roller, said supply control means dispensing the film web from the roller at a controlled variable supply speed according to said load model input independent of sensed variations in the tension of the film web and sensed variations in the demand rate for the film web downstream of the roller, wherein said means for defining a model includes a plurality of pulleys mounted in an arrangement in which the pulleys define vertices of a polygon with edge length ratios and angles equal to those of a cross section of the load, and power belt means encircling the pulleys and engaging the roller and increasing and decreasing the rotation speed of the roller according to the angular position of the roller relative to the arrangement of pulleys during wrapping.

An apparatus for wrapping a film web around a load with a cross-section which causes variations in demand rate for the film web during wrapping, comprising:

• a frame;
• dispenser means mounted on the frame for revolving around the load, and having at least one feeding roller for dispensing film web;
• and
• supply speed control means rotatably coupled to the roller through a mechanism other than the film web for increasing and decreasing the rotation speed of the roller, said supply speed control means comprising means defining a predetermined model substantially approximating the cross-sectional configuration of the load for rotatably controlling the speed of said roller in response to input from said load model, said input being independent of both actual sensed variations in the tension of the film web and actual sensed variations in the demand rate for the film web downstream of the roller, said supply control means dispensing the film web from the roller at a controlled variable supply speed according to said load model input independent of sensed variation in the tension of the film web and sensed variations in the demand rate for the film web downstream of the roller, wherein said means for defining a model includes a stationary track mounted on the frame and generally defining a plane parallel to the plane defined by the revolution of the dispenser means, the roller including contact roll means for engaging and having its speed controlled by the track during relative rotation of the dispenser means and the track, the track including means for increasing and decreasing the rotation speed of the contact roll means and for increasing and decreasing the rotation speed of the roller according to the angular position of the roller relative to the track during wrapping.

A process for wrapping a film web around a load with a cross-section which causes variations in demand rate for the film web during wrapping, comprising:

• forming a predetermined model substantially approximating the cross-sectional configuration of the load;
• revolving a film web dispenser around the load;
• dispensing the film web from at least one roller in the film web dispenser to wrap the load;
• and
• controlling the rotation speed of the roller by rotatably controlling the speed of the roller through a mechanism other than the film web in response to input from said load model, said input being independent of both actual sensed variations in the tension of the film web and actual sensed variations in the demand rate for the film web downstream of the roller and dispensing the film web from the roller at a controlled variable supply speed according to said load model input independent of sensed variations in the tension of the film web and sensed variations in the demand rate for the film web downstream of the roller.

A process for wrapping film web around a load with a cross-section which causes variations in demand rate for the film web during wrapping, comprising:

• forming a predetermined model substantially approximating the cross-sectional configuration of the load;
• revolving a film web dispenser and elongation mechanism around the load;
• elongating the film web with the elongation mechanism in the film web dispenser;
• dispensing the film web from the elongation mechanism to wrap the load;
• and
• controlling the dispensing speed of the elongation mechanism through a mechanism other than the film web in response to input from said load model, said input being independent of both actual sensed variations in the tension of the film web and actual sensed variation in the demand rate for the film web downstream of the elongation mechanism, and dispensing the film web from the elongation mechanism at a controlled variable supply speed according to said load model input independent of sensed variations in the tension of the film web and sensed variations in the demand rate for the film web downstream of the downstream roller.

A process for wrapping a film web around a load with a cross-section which causes variations in demand rate for the film web during wrapping, comprising:

• forming a predetermined model substantially approximating the cross-sectional configuration at the load;
• revolving a film web dispenser and elongation mechanism around the load;
• elongating the film web between upstream and downstream rollers in the elongation mechanism of the film web dispenser by rotating the upstream and downstream rollers at a constant rotation speed ratio;
• dispensing the film web from the downstream roller in the film web dispenser to wrap the load;
• and
• increasing and decreasing the rotation speed of the upstream and downstream rollers by rotatably controlling the speed of the rollers through a mechanism other than the film web and in response to input from said load model, said input being independent of both actual sensed variations in the tension of the film web and actual sensed variations in the demand rate for film web downstream of the downstream roller, and dispensing the film web from the elongation mechanism at a controlled variable supply speed according to said load model input independent of sensed variations in the tension of the film web and sensed variations in the demand rate for the film web downstream of the downstream roller.