Extended dwell heat sealer

Claim 2

In a web handling machine for advancing a web and having a web contacting device such as a seal bar or the like, a control system for said web contacting device comprising a driven rotary shaft extending across the path of a moving web, laterally spaced drive yokes mounted on said shaft and straddling the web, a support bar parallel to said shaft, a slide block rotatably mounted on each end of said support bar and slidably mounted on the adjacent drive yoke for movement toward and away from the axis of said shaft, cam folloWer means mounted on each end of said support bar, camming means engaged by each of said cam follower means for guiding said support bar in an irregular orbit about the axis of said shaft, said orbit including a path parallel to the path of web motion, a web contacting device carried by said support bar, and a drive train connected to said driven shaft for regulating the instantaneous angular velocity of said shaft to render the velocity of said web contacting device along said path equal to that of the web.

Claim 3

Apparatus according to claim 1 and a heated element mounted on said web contacting device, a thin and wide solid metallic recurved electrical conductor connected to said heated element, and insulating means connecting the other end of said conductor to said shaft, said conductor having a relatively large cross sectional area and its narrow dimension transverse to said shaft to accommodate repeated flexure and large electrical currents without inhibiting the relative motion between said shaft and said web contacting device.

Claim 4

Apparatus according to claim 1 and interrupted conveying means at each side of said shaft for supporting the moving web, and a web support member secured to said shaft for rotation therewith, said member comprising a circumferentially interrupted hollow cylinder terminating in edges adjacent said web contacting device, said member being in supporting relation with said web when said web contacting device is remote from the web.

Claim 5

Apparatus according to claim 2 wherein said insulating means includes a dielectric plug extending transversely through said shaft and enclosing said conductor, said shaft having an axial bore intersecting said plug, and an electrode in said bore having a forked end extending into a transverse aperture of said plug in gripping relation with said conductor.

Claim 6

In a web handling machine having a seal bar, a velocity control system for said seal bar comprising a driven rotary shaft extending across the path of a moving web, a drive yoke mounted on each end portion of said shaft, two support bars straddling said shaft, a rotatable slide block mounted on each end of said support bars in sliding engagement with the adjacent drive yoke, cam follower means projecting from each end of said support bars, camming means engaged by each of said cam follower means for guiding said support bar in an irregular orbit about the axis of said shaft, said orbit including a path parallel to the web, a seal bar carried by each of said support bars, an electrically heated element mounted on each of said seal bars, a thin and wide solid metallic electrical conductor extending through said shaft, said conductor being recurved at each side of said shaft and connected to the adjacent one of said electrically heated elements, said conductor having a relatively large cross sectional area and its narrow dimension transverse to said shaft to accommodate repeated flexure from the relative motion between said shaft and said heated elements, and a drive train connected to said driven shaft for regulating the instantaneous angular velocity of said driven shaft.

Claim 7

In a web handling machine having a seal bar, a velocity control system for said seal bar comprising a driven rotary shaft extending across the path of a moving web, a drive yoke mounted on each end portion of said shaft, two support bars straddling said shaft, a rotatable slide block mounted on each end of said support bars in sliding engagement with the adjacent drive yoke, cam follower means projecting from each end of said support bars, camming means engaged by each of said cam follower means for guiding said support bar in an irregular orbit about the axis of said shaft, said orbit including a path parallel to the web, a seal bar carried by each of said support bars, an electrically heated element mounted on each of said seal bars, a thin and wide solid metallic electrical conductor extending through said shaft, said conductor being recurved at each side of said shaft and connected to the adjacent one of said electrically heated elements, said conductor having a relatively large cross sectional area and its narrow dimension transverse to said shaft to accommodate repeated flexure from the relative motion between said shaft and said heated elements, and a drive train connected to said driven shaft for regulating the instantaneous angular velocity of said driven shaft.

Claim 8

In a web handling machine for advancing a heat sealable web and having a web contacting device including an electrically heated seal bar or the like, a control system for said web contacting device comprising driven rotary shaft means extending transversely of the path of a moving web, laterally spaced drive yokes mounted on said shaft means and straddling the web, a support bar parallel to the shaft means, a slide block rotatably mounted on each end of said support bar and slidably mounted on the adjacent drive yoke for movement toward and away from the axis of said shaft means, cam follower means mounted on each end of said support bar, camming means engaged by each of said cam follower means for guiding said support bar in an irregular orbit about the axis of said shaft means, said orbit including a path parallel to the path of web motion, an electrically heated web contacting dEvice carried by said support bar, means defining an electrical conductor for conducting electricity to said electrically heated web contacting device, and a drive train connected to said driven shaft for regulating the instantaneous angular velocity of said shaft to render the velocity of said web contacting device along said path equal to that of the web.

Claim 9

In a web handling machine for advancing a heat sealable web and having a web contacting device including an electrically heated seal bar or the like, a control system for said web contacting device comprising driven rotary shaft means extending transversely of the path of a moving web, laterally spaced drive yokes mounted on said shaft means and straddling the web, a support bar parallel to the shaft means, a slide block rotatably mounted on each end of said support bar and slidably mounted on the adjacent drive yoke for movement toward and away from the axis of said shaft means, cam follower means mounted on each end of said support bar, camming means engaged by each of said cam follower means for guiding said support bar in an irregular orbit about the axis of said shaft means, said orbit including a path parallel to the path of web motion, an electrically heated web contacting dEvice carried by said support bar, means defining an electrical conductor for conducting electricity to said electrically heated web contacting device, and a drive train connected to said driven shaft for regulating the instantaneous angular velocity of said shaft to render the velocity of said web contacting device along said path equal to that of the web.

Claim 10

An apparatus according to claim 6 and a heat element included in said electrically heated web contacting device, said electrical conductor means including a thin and wide solid metallic curved electrical conductor connected to said heated element, and electrical conduit means extending into said shaft means and connected to said flat conductor, said flat conductor having a relatively large cross sectional area and its narrow dimension being transverse to said shaft means to accommodate repeated flexure and large electrical currents without inhibiting the relative motion between said shaft and said web contacting device.

Claim 11

In a web handling machine having a seal bar, a velocity control system for said seal bar comprising a driven rotary shaft means extending transversely of the path of a moving web, a drive yoke mounted on end portions of said shaft means on opposite sides of said web, a support bar extending parallel to said shaft, a rotatable slide block mounted on each end of said support bar in sliding engagement with the adjacent drive yoke, cam follower means projecting from each end of said support bar, camming means engaged by each of said cam follower means for guiding said support bar in an irregular orbit about the axis of said shaft, said orbit including a path parallel to the web, a seal bar carried by said support bar, an electrically heated element mounted on said seal bar, first electrical conductor means extending into said shaft means, a thin and wide solid metallic electrical conductor connected to said first conductor, said thin and wide conductor being curved at one side of said shaft and connected to said electrically heated element, said thin and wide conductor having a relatively large cross sectional area and its narrow dimension being transverse to said shaft to accommodate repeated flexure from the relative motion between said shaft and said heated element, and a drive train connected to said driven shaft for regulating the instantaneous angular velocity of said driven shaft.

Claim 12

In a web handling machine having a seal bar, a velocity control system for said seal bar comprising a driven rotary shaft means extending transversely of the path of a moving web, a drive yoke mounted on end portions of said shaft means on opposite sides of said web, a support bar extending parallel to said shaft, a rotatable slide block mounted on each end of said support bar in sliding engagement with the adjacent drive yoke, cam follower means projecting from each end of said support bar, camming means engaged by each of said cam follower means for guiding said support bar in an irregular orbit about the axis of said shaft, said orbit including a path parallel to the web, a seal bar carried by said support bar, an electrically heated element mounted on said seal bar, first electrical conductor means extending into said shaft means, a thin and wide solid metallic electrical conductor connected to said first conductor, said thin and wide conductor being curved at one side of said shaft and connected to said electrically heated element, said thin and wide conductor having a relatively large cross sectional area and its narrow dimension being transverse to said shaft to accommodate repeated flexure from the relative motion between said shaft and said heated element, and a drive train connected to said driven shaft for regulating the instantaneous angular velocity of said driven shaft.