Heating element and packaging machine equipped therewith

Claim 2

In a packaging machine for applying a heat-softenable film to a product: a. a support structure defining a chamber open on a side; b. a film-supporting frame; c. means connecting said support structure and said filmsupporting frame for relative movement toward and away from each other whereby said open side of said chamber is substantially closable by said frame when supporting a film; d. at least one heater unit supported by said support structure in said chamber; e. said heater unit comprising: 1. an elongated core member extending between spaced connections to said support structure; 2. a heater element member comprising a thin ribbon of electrical resistance material wound in a helical configuration about said core member, said ribbon of resistance material having been stress relieved in said helical configuration and being in a substantially relaxed condition on said core member; 3. said members having confronting surfaces formed for engagement at a plurality of small area contact locations and spaced apart between said contact locations so that heat losses from said heater member by conduction to said core member are minimized and convective heat transfer to air in the vicinity of said heater element is maximized; 4. electrical connector means supported at opposite ends of said heater member and electrically connected to said heater member; and, f. said heater member being electrically resistance heated on completion of an electrical circuit therethrough and heating air surrounding said unit to create convective air currents in said chamber for heating and softening film carried on said film-supporting frame.

Claim 3

a heater element member comprising a thin ribbon of electrical resistance heating material helically wound about said core member;

Claim 4

a heater element member comprising a thin ribbon of electrical resistance heating material helically wound about said core member;

Claim 5

a ribbonlike electrical resistance heater member formed in a helical configuration extending about said core member and supported thereby, said heater member having been stress relieved in said helical configuration and being in a substantially relaxed condition on said core member;

Claim 6

a ribbonlike electrical resistance heater member formed in a helical configuration extending about said core member and supported thereby, said heater member having been stress relieved in said helical configuration and being in a substantially relaxed condition on said core member;

Claim 7

a heater element member comprising a thin ribbon of electrical resistance material wound in a helical configuration about said core member, said ribbon of resistance material having been stress relieved in said helical configuration and being in a substantially relaxed condition on said core member;

Claim 8

a heater element member comprising a thin ribbon of electrical resistance material wound in a helical configuration about said core member, said ribbon of resistance material having been stress relieved in said helical configuration and being in a substantially relaxed condition on said core member;

Claim 9

In a packaging machine as claimed in claim 1 wherein said core member is composed of a material which is substantially transparent to radiant heat whereby radiant heat transfer to said core member from said heater member is minimized.

Claim 10

In a packaging machine as claimed in claim 1 wherein said support structure includes a radiant heat reflector member and said heater unit is supported adjacent said reflector, said reflector operative to reflect radiant heat toward said open side of said chamber.

Claim 11

said members having confronting surfaces formed for engagement at a plurality of small area contact locations and spaced apart between said contact locations so that heat losses from said heater member by conduction to said core member are minimized and convective heat transfer to air in the vicinity of said heater element is maximized;

Claim 12

said members having confronting surfaces formed for engagement at a plurality of small area contact locations and spaced apart between said contact locations so that heat losses from said heater member by conduction to said core member are minimized and convective heat transfer to air in the vicinity of said heater element is maximized;

Claim 13

said ribbonlike member haVing a thickness which is extremely small as compared to its width and defining transverse corrugations;

Claim 14

said ribbonlike member haVing a thickness which is extremely small as compared to its width and defining transverse corrugations;

Claim 15

said members having confronting surfaces formed for engagement at a plurality of small area contact locations and spaced apart between said contact locations so that heat losses from said heater member by conduction to said core member are minimized and convective heat transfer to air in the vicinity of said heater element is maximized;

Claim 16

said members having confronting surfaces formed for engagement at a plurality of small area contact locations and spaced apart between said contact locations so that heat losses from said heater member by conduction to said core member are minimized and convective heat transfer to air in the vicinity of said heater element is maximized;

Claim 17

electrical connector means supported at opposite ends of said heater member and electrically connected to said heater member; and, f. said heater member being electrically resistance heated on completion of an electrical circuit therethrough and heating air surrounding said unit to create convective air currents in said chamber for heating and softening film carried on said film-supporting frame.

Claim 18

electrical connector means supported at opposite ends of said heater member and electrically connected to said heater member; and, f. said heater member being electrically resistance heated on completion of an electrical circuit therethrough and heating air surrounding said unit to create convective air currents in said chamber for heating and softening film carried on said film-supporting frame.

Claim 19

In a packaging machine as claimed in claim 1 wherein said ribbon is corrugated transverse to its length, said contact locations being defined by engagement between portions of said corrugations and said core member, the remaining surfaces of said corrugations disposed for convective heat transfer with air in said chamber.

Claim 20

said ribbonlike member engaging said core member at a series of small area low friction contact locations on a helical path along said core member to minimize conductive heat transfer to said core member and expose a maximum area of said resistance heated member to ambient air whereby to create turbulent circulation of air about said unit; and, e. said heater member being freely slidable on said core member while supported thereby and said heater being devoid of means compensating for thermal expansion and contraction of said heater member relative to said core member.

Claim 21

said ribbonlike member engaging said core member at a series of small area low friction contact locations on a helical path along said core member to minimize conductive heat transfer to said core member and expose a maximum area of said resistance heated member to ambient air whereby to create turbulent circulation of air about said unit; and, e. said heater member being freely slidable on said core member while supported thereby and said heater being devoid of means compensating for thermal expansion and contraction of said heater member relative to said core member.

Claim 22

electrical connector means connected to said heater element member comprising end cap members supported on opposite ends of said core member and fastener Members for clamping said heater element member to said end caps; f. said heater element member being electrically resistance heated on completion of an electrical circuit therethrough and heating air surrounding said unit to create convective air currents in said chamber for heating and softening film carried on said film-supporting frame; and g. said end cap members each including a circumferential groove and said fastener members each comprising a snapring resiliently clamping said heater element member in said groove.

Claim 23

electrical connector means connected to said heater element member comprising end cap members supported on opposite ends of said core member and fastener Members for clamping said heater element member to said end caps; f. said heater element member being electrically resistance heated on completion of an electrical circuit therethrough and heating air surrounding said unit to create convective air currents in said chamber for heating and softening film carried on said film-supporting frame; and g. said end cap members each including a circumferential groove and said fastener members each comprising a snapring resiliently clamping said heater element member in said groove.

Claim 24

In a packaging machine as claimed in claim 1 wherein said electrical connector means each comprises an end cap member supported on an end of said core member and a fastener member for clamping said heater element to said end cap.

Claim 25

In a packaging machine as claimed in claim 5 wherein said end caps each include a circumferential groove and said fastener member comprises a snapring resiliently clamping said element in said groove.

Claim 26

In a packaging machine as claimed in claim 1 wherein the pitch of said helical coils of said heater member varies along said core member so that the distribution of heat produced along said heater member can be controlled by varying the pitch of said coils.

Claim 27

In a packaging machine as claimed in claim 1 wherein said core member is of generally star-shaped cross-sectional configuration.

Claim 28

An electrically energized heater assembly comprising: a. an elongated core member defining a relatively smooth substantially continuous outer peripheral surface and comprised at least in part of a material which is substantially nonabsorbent of radiant heat; b. a ribbonlike heater element member of electrical resistance material formed in a helical configuration extending about said core member and supported on said core at spaced locations, said ribbonlike element having been stress relieved in said helical configuration and being in a substantially relaxed condition on said core member; c. said ribbonlike element having transverse corrugations including first corrugation portions engaging said core member to define said spaced locations and second corrugation portions spaced from said core member; d. said spaced support locations defined by small low friction contact areas on said members to minimize heat conduction from said heater member to said core member, to maximize the exposure of said heater element member to ambient atmosphere and to minimize the frictional engagement between said heater member and said core member; e. said second corrugation portions spaced from said core member for transferring heat to said ambient atmosphere and creating a turbulent flow of said atmosphere about said assembly; and, f. electrical contact elements connected to said heater member adjacent ends of said core member.

Claim 29

An electrically energized heater assembly comprising: a. an elongated core member defining a relatively smooth substantially continuous outer peripheral surface and comprised at least in part of a material which is substantially nonabsorbent of radiant heat; b. a ribbonlike heater element member of electrical resistance material formed in a helical configuration extending about said core member and supported on said core at spaced locations, said ribbonlike element having been stress relieved in said helical configuration and being in a substantially relaxed condition on said core member; c. said ribbonlike element having transverse corrugations including first corrugation portions engaging said core member to define said spaced locations and second corrugation portions spaced from said core member; d. said spaced support locations defined by small low friction contact areas on said members to minimize heat conduction from said heater member to said core member, to maximize the exposure of said heater element member to ambient atmosphere and to minimize the frictional engagement between said heater member and said core member; e. said second corrugation portions spaced from said core member for transferring heat to said ambient atmosphere and creating a turbulent flow of said atmosphere about said assembly; and, f. electrical contact elements connected to said heater member adjacent ends of said core member.

Claim 30

An electrical heater as claimed in claim 9 wherein said core member material is quartz.

Claim 31

The assembly of claim 9 wherein said contact elements are a spaced pair of cuplike members telescoped over ends of the core member.

Claim 32

The assembly claimed in claim 9 wherein the pitch of said helically wound heater element member on said core member is varied proceeding along said core member whereby the quantity of heat transferred from said assembly is nonuniform along said assembly.

Claim 33

The assembly claimed in claim 12 wherein said heater element member is stress relieved in situ on said core member.

Claim 34

The assembly claimed in claim 9 wherein said core member and said heater element are unrestrained against thermal expansion and contraction and said assembly is devoid of support means compensating for thermal expansion or contraction.

Claim 35

A convection heater comprising: a. a support structure defining a chamber having an open side; b. at least one electrically energized heater unit in said chamber for transferring heat to air in said chamber; c. means for detachably connecting said at least one unit to said support structure; d. said heater unit comprising:

Claim 36

A convection heater comprising: a. a support structure defining a chamber having an open side; b. at least one electrically energized heater unit in said chamber for transferring heat to air in said chamber; c. means for detachably connecting said at least one unit to said support structure; d. said heater unit comprising:

Claim 37

An electrical heater assembly comprising: a. an elongated core member; b. a heater element member supported on said core member; c. means for connecting said heater element member to an electrical power supply; d. said heater element member comprising a ribbon of transversely corrugated electrical resistance material wound in a helical configuration about said core member, portions of corrugations lightly engaging said core member at spaced locations and with said ribbon unrestrained against movement along said core member; and, e. said resistance material being stress relieved in said helical configuration whereby helical coils of said heater member are substantially relaxed when supported on said core member.

Claim 38

An electrical heater assembly comprising: a. an elongated core member; b. a heater element member supported on said core member; c. means for connecting said heater element member to an electrical power supply; d. said heater element member comprising a ribbon of transversely corrugated electrical resistance material wound in a helical configuration about said core member, portions of corrugations lightly engaging said core member at spaced locations and with said ribbon unrestrained against movement along said core member; and, e. said resistance material being stress relieved in said helical configuration whereby helical coils of said heater member are substantially relaxed when supported on said core member.

Claim 39

A heater assembly as claimed in claim 16 wherein coils of said helically configured heater member are nonuniformly distributed along said core member.

Claim 42

In a packaging machine for applying a heat-softenable film to a product: a. a support structure defining a chamber open on a side; b. a film-supporting frame; c. means connecting said support structure and said film-supporting frame for relative movement toward and away from each other whereby said open side of said chamber is substantially closable by said frame when supporting a film; d. at least one heater unit supported by said support structure in said chamber; e. said heater unit comprising:

Claim 43

In a packaging machine for applying a heat-softenable film to a product: a. a support structure defining a chamber open on a side; b. a film-supporting frame; c. means connecting said support structure and said film-supporting frame for relative movement toward and away from each other whereby said open side of said chamber is substantially closable by said frame when supporting a film; d. at least one heater unit supported by said support structure in said chamber; e. said heater unit comprising:

Claim 44

An electrically energized heater assembly comprising: a. an elongated core member defining a relatively smooth substantially continuous outer peripheral surface and comprised at least in part of a material which does not absorb radiant heat; b. a ribbonlike heater element member of electrical resistance heating material wound helically about said core and supported on said core at spaced locations; c. said ribbonlike element having transverse corrugations including portions engaging said core member to define said spaced locations and portions spaced from said core member; d. said spaced locations defined by small low friction contact areas on said members to minimize heat conduction from said heater member to said core member, to maximize the exposure of said heater element member to ambient atmosphere and to minimize the extent of the frictional engagement between said heater member and said core member; e. said corrugation portions spaced from said core member transferring heat to said ambient atmosphere and creating a turbulent flow of said atmosphere about said assembly; f. electrical contact elements connected to said heater member adjacent ends of said core member, said contact elements comprising cuplike members telescoped over opposite ends of the core member, each of said cuplike members having a peripheral groove, end portions of the heater element member projecting into a respective groove; and, g. a snapring in each groove for tightly compressing a respective end portion of said heater element against the base of the respective groove, at least one of said cuplike members or said snaprings in electrical contact with said heater element member at said end portions.

Claim 45

An electrically energized heater assembly comprising: a. an elongated core member defining a relatively smooth substantially continuous outer peripheral surface and comprised at least in part of a material which does not absorb radiant heat; b. a ribbonlike heater element member of electrical resistance heating material wound helically about said core and supported on said core at spaced locations; c. said ribbonlike element having transverse corrugations including portions engaging said core member to define said spaced locations and portions spaced from said core member; d. said spaced locations defined by small low friction contact areas on said members to minimize heat conduction from said heater member to said core member, to maximize the exposure of said heater element member to ambient atmosphere and to minimize the extent of the frictional engagement between said heater member and said core member; e. said corrugation portions spaced from said core member transferring heat to said ambient atmosphere and creating a turbulent flow of said atmosphere about said assembly; f. electrical contact elements connected to said heater member adjacent ends of said core member, said contact elements comprising cuplike members telescoped over opposite ends of the core member, each of said cuplike members having a peripheral groove, end portions of the heater element member projecting into a respective groove; and, g. a snapring in each groove for tightly compressing a respective end portion of said heater element against the base of the respective groove, at least one of said cuplike members or said snaprings in electrical contact with said heater element member at said end portions.