Packaging machine and method

A method of interrupting operation of a packaging machine during a sealing operation comprising:

• a) directing a light beam from a source connected to one component of the sealing mechanism against a reflective surface on another component of the sealing mechanism;
• b) actuating a prime mover to move the components relatively toward one another into engagement with portions of a package being formed and thereby compress the portions between a hot element and a seal pad respectively forming portions of the components;
• c) detecting reflections of such beam with a light beam receiver as the
• prime mover is actuated;
• and
• d) interrupting the prime mover actuation causing relative component movement toward one another if the light beam receiver ceases to receive beam reflections during a predetermined portion of the component relative movement.

In a machine having a housing and frame structure and adapted to sequentially load and seal bags of a chain of interconnected and preopened bags, an improved sealing assembly comprising:

• a) a heater bar element connected to the structure;
• b) a sealing pad support connected to the structure and a sealing pad element carried by the support;
• c) a prime mover operatively connected to and interposed between the elements for effecting relative motion between a storage position wherein the elements are spaced to a sealing position wherein a bag to be sealed is compressed between the elements;
• d) a mechanism including two reflective surfaces connected to one of the elements;
• e) a light source positioned to impinge a light beam on a first of the reflective surfaces for reflection of the light beam onto a second of the reflective surfaces during an initial portion of the relative motion from the storage to the sealing portions;
• f) a light beam receiver mounted opposite the second reflective surface and positioned to receive reflected light from the second surface during said initial portion of relative motion, the receiver being adapted to emit a signal when detecting such reflected light, and,
• g) control means operatively connected to the receiver and adapted to stop relative motion from the storage to the sealing position during such initial portion if the receiver ceases to emit a signal in response to detected light.

A package sealing mechanism comprising:

• a) housing and frame structure;
• b) relatively moveable heater bar and seal pad sub-assemblies connected to the structure;
• c) a prime mover operably connected to the sub-assemblies selectively to cause relative sub-assembly motion from a spaced package receiving and discharge position to a package sealing position and return;
• d) a light source and a spaced light receiver forming a part of the mechanism and positioned such that a beam emitted by the source along a beam path is received by the receiver under at least certain conditions;
• e) a beam disrupter movably mounted on one of the sub-assemblies and shiftable between a beam disruption position blocking the path and a beam passage position spaced from the path;
• and
• f) control means operably connected to the receiver and the prime mover and adapted to abort a sealing operation in response to signals from the receiver indicating an undesired light beam condition.

In a machine having a housing and frame structure and adapted to sequentially load and seal bags of a chain of interconnected and preopened bags, an improved sealing assembly comprising:

• a) a heater bar mounted on the structure;
• b) the assembly including a mounted sealing pad support and a sealing pad carried by the support;
• c) a prime mover operatively connected to the support and to the heater bar for effecting relative motion between a storage position wherein the pad is spaced from a sealing position wherein a bag to be sealed is compressed between the pad and the heater bar;
• d) the support including two reflective surfaces;
• e) a light source carried by the structure and positioned to impinge a light beam on a first of the reflective surfaces which reflects the light beam onto a second of the reflective surfaces when the prime mover is in the storage position and during an initial portion of the relative motions of the support from the storage to the sealing portions;
• f) a light beam receiver mounted on the support opposite the second reflective surface positioned to receive reflected light from the second surface when the prime mover is in the storage position, the receiver being adapted to emit a signal when detecting such reflected light, and,
• g) control means operatively connected to the receiver and adapted to stop relative motion from the storage to the sealing position during such initial portion if the receiver ceases to emit a signal in response to detected light.

A packaging machine for loading bags including a bag sealing section, the sealing section comprising:

• a) a frame structure;
• b) a light beam source mounted on the frame structure and adapted to emit an intermittent light beam;
• c) a heater bar connected to the frame structure;
• d) a reciprocatable support assembly movably connected to the frame structure and including a prime mover;
• e) a clamping sub-assembly connected to the support assembly for bringing a loaded bag into contact with the heater bar and clamping the loaded bag against the heater bar, the clamping sub-assembly including a seal bar and a reciprocatable housing for the seal bar;
• f) at least one reflective device located in the path of the light source beam for reflecting such light beam when emitted by the light beam source, the reflective device being mounted on the housing for the seal bar;
• g) a receiver for receiving a reflection from the reflective device;
• h) control means for sensing reception of the reflection by the receiver and controlling operation of said bag-sealing section based upon such reception;
• i) a cavity defined within the clamping sub-assembly for each reflective device, each reflective device entering its respective cavity upon reciprocation of the housing during contact between the heater bar and the clamping sub-assembly thereby disrupting reflection of the light beam;
• and,
• j) a sensing device for sensing the clamping sub-assembly meeting the heater bar.