Granted Patent B2

US 6,871,584 · App. 10/446,591 · Granted Mar 29, 2005

Abstract

Claims (16)

1. A self-cleaning limit switch for a strapping head of a strapping machine of the type having a feed assembly and a chute, the strapping machine configured to convey a strapping material into the strapping head, into and around the chute and to exit the chute and return to the strapping head, the strapping machine configured to receive first and second courses of associated strapping material, position, tension and seal the strapping material around a load, the strapping head including internal and external limit switch channels formed therein, the limit switch comprising:

a sliding element having internal and external sliding positions rigidly connected to one another, the internal sliding portion positioned in the strapping head internal limit switch channel and the external sliding portion positioned in the strapping head external limit switch channel, each of the internal and external sliding portions including an inclined surface at a rearward end thereof, each of the internal and external sliding portions including an upstanding wall surface at a forward end thereof, the internal sliding portion having a lip thereon for engaging the second course of strapping material, the external sliding portion having a position indicating element thereon; and

means for detecting the presence or absence of the position indicating element,

wherein the sliding element is movable between a strap not present position when the second course of strapping material is not present at the limit switch, and a strap present position when the second course of strapping material is present at the limit switch, the second course of strapping material contacting the internal portion lip of the sliding element to urge the limit switch from the strap not present position to the strap present position, and wherein movement of the sliding element between the strap present and strap not present positions urges the sliding element inclined surfaces to dislodge debris that is present in the strapping head internal and external channels.

2. The self-cleaning limit switch in accordance with claim 1 wherein the internal and external sliding portions are connected to one another by a fastener.

3. The self-cleaning limit switch in accordance with claim 1 wherein the position indicating element is a projecting finger and wherein the means for detecting the presence or absence of the position indicating element is a proximity sensor configured to detect the present or absence of the projecting finger.

4. The self-cleaning limit switch in accordance with claim 1 including a biasing element for biasing the sliding element to the strap not present position.

5. A strapping machine for positioning a strapping material around an associated load, tensioning and sealing the strapping material to itself around the load, comprising:

a frame;

a chute defining a strap path, the chute being mounted to the frame;

a strapping head mounted to the frame and configured for receipt at the chute, the strapping head configured to receive first and second courses of associated strapping material, position, tension and seal the strapping material around a load, the strapping head including internal and external limit switch channels formed therein, the strapping head including a self-cleaning limit switch mounted thereto having a sliding element having internal and external sliding positions rigidly connected to one another, the internal sliding portion positioned in the strapping head internal limit switch channel and the external sliding portion positioned in the strapping head external limit switch channel, each of the interal and external sliding portions including an upstanding wall surface at a forward end thereof, the internal sliding portion having a lip thereon for engaging the second course of strapping material, the external sliding portion having a position indicating element thereon and means for detecting the presence or absence of the position indicating element,

wherein the sliding element is movable between a strap not present position when the second course of strapping material is not present at the limit switch, and a strap present position when the second course of strapping material is present at the limit switch, the second course of strapping material contacting the internal portion lip of the sliding element to urge the limit switch from the strap not present position to the strap present position, and wherein movement of the sliding element between the strap present and strap not present positions urges the sliding element inclined surfaces to dislodge debris that is present in the strapping head internal and external channels.

6. The strapping machine in accordance with claim 5 wherein the internal and external sliding portions are connected to one another by a fastener.

7. The strapping machine in accordance with claim 5 wherein the position indicating element is a projecting finger and wherein the means for detecting the presence or absence of the position indicating element is a proximity sensor configured to detect the presence of the projecting finger.

8. The strapping machine in accordance with claim 5 including a biasing element for biasing the sliding element to the strap not present position.

9. The strapping machine in accordance with claim 5 wherein the internal and external sliding portions include an inclined surface at a rearward end thereof.

Assignments (7)