Title:
HEATING APPARATUS FOR A PRINTING PRESS
United States Patent 3629555
Abstract:
A printing press heating apparatus of modular construction providing a selected size and extent of heating surface and supported in its heat exchange position with adequate allowance for thermal expansion and contraction thereof.
US Patent References:
Griddle heater or stove
Lewin - April 1929 - 1711472
Electric thawer for pipes
Nordstrom - September 1950 - 2523876
Electric heaters
Knoll - June 1957 - 2795682
Detachable ice and snow melting panels for traffic bearing surfaces
Jamison - November 1959 - 2912555
Panel electric heater
Hicks - January 1960 - 2922866
Griddle heater or stove
Lewin - April 1929 - 1711472
Electric thawer for pipes
Nordstrom - September 1950 - 2523876
Electric heaters
Knoll - June 1957 - 2795682
Detachable ice and snow melting panels for traffic bearing surfaces
Jamison - November 1959 - 2912555
Panel electric heater
Hicks - January 1960 - 2922866
Application Number:
05/052541
Publication Date:
12/21/1971
Filing Date:
07/06/1970
View Patent Images:
Export Citation:
Assignee:
Herbert Products International (Westbury, NY)
Primary Class:
Other Classes:
219/388, 338/285, 219/552, 219/460.100, 118/642, 219/477, 392/435, 219/478, 219/216
International Classes:
B41F23/04; H05B3/00; B41F23/00; H05B3/06
Field of Search:
219/388,345,347,525,553,216,213,476,477,478,351-352,464,460,411 338/316,285,280
US Patent References:
Primary Examiner:
Mayewsky, Volodymyr Y.
Claims:
What is claimed is
1. An offset printing press heater comprising plural rectangular bodies fabricated of quartz material of a prescribed thickness,
2. An offset printing press heater as defined in claim 1 including support means therefore comprising a first set of cooperating interfitting male and female support members operatively arranged along upper and lower edges of said support frame so as to be slidable, in response to thermal expansion and contraction of said heater, along two horizontally oriented axes,
3. An offset printing press heater as defined in claim 2 wherein said first set of cooperating interfitting male and female support members comprises plural cylindrical elements projected within cooperating cylindrical bores so that relative rotative movement therebetween is possible to facilitate tilting adjustment of said heater.
4. An offset printing press heater as defined in claim 3 wherein members having said cylindrical bores are mounted on said support frame and said cooperating cylindrical elements project from clearance positions remote from said support frame such that said support frame is slidably adjustable throughout a range of positions along said cylindrical elements.
1. An offset printing press heater comprising plural rectangular bodies fabricated of quartz material of a prescribed thickness,
2. An offset printing press heater as defined in claim 1 including support means therefore comprising a first set of cooperating interfitting male and female support members operatively arranged along upper and lower edges of said support frame so as to be slidable, in response to thermal expansion and contraction of said heater, along two horizontally oriented axes,
3. An offset printing press heater as defined in claim 2 wherein said first set of cooperating interfitting male and female support members comprises plural cylindrical elements projected within cooperating cylindrical bores so that relative rotative movement therebetween is possible to facilitate tilting adjustment of said heater.
4. An offset printing press heater as defined in claim 3 wherein members having said cylindrical bores are mounted on said support frame and said cooperating cylindrical elements project from clearance positions remote from said support frame such that said support frame is slidably adjustable throughout a range of positions along said cylindrical elements.
Description:
The present invention relates generally to a heating apparatus for a printing press, and more particularly to a heater adapted to be used with an offset printing press to quickly and efficiently dry the ink on the material printed by the press.
Infrared heaters are currently in common use in offset printing presses to speed up the drying of printing inks and have, for all practical purposes, replaced the use of drying powders and other such techniques. The manner of incorporating the heater as part of the press, however, has not been entirely satisfactory. For example, the extent of printing which has to be dried usually varies considerably and, for efficiency's sake, the capacity of the heater should therefore vary correspondingly so that the use of either excessive or insufficient heat is minimized. Another major problem involves mounting the heater to avoid inadvertent movement thereof during printing operation of the press and yet having adequate provision in the mounting for thermal expansion and contraction of the heater.
Additionally, heat control of the heater has been a major problem. When an excessive heat is applied, this is effective to dry the inks, but it may also cause shrinkage of the paper. An insufficient heat brings the oils or vehicle to the surface, leaving the ink still wet.
Broadly, it is an object of the present invention to provide an improved printing press heater overcoming the foregoing and other shortcomings of the prior art. Specifically, it is an object to provide a heater formed of an assembly of heating units so that the number of units selected for assembly significantly determines the effective heating surface or area thereof. Also the supports for the heater are expandable and contractable along transverse axes to thereby allow for thermal expansion and contraction of the heater.
A printing press heater demonstrating objects and advantages of the present invention includes heating units appropriately assembled in first frame members which, in a select number, are in turn mounted in a second frame, and a support for the second frame that adequately allows for thermal expansion and contraction size changes. Specifically, the support includes a first set of cooperating members having provision for relative movement, as may be occasioned by thermal expansion and contraction, along horizontal axes, and a second set of cooperating members supporting said first set which has provision for a similar allowance for expansion and contracting movements, but along vertical axes. Thus, the support allows for thermal expansion and contraction of the heater along transverse axes.
The above brief description, as well as further objects, features and advantages of the present invention, will be more fully appreciated by reference to the following detailed description of a presently preferred, but nonetheless illustrative embodiment in accordance with the present invention, when taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is an exploded perspective view of a printing press heating apparatus according to the present invention, portions thereof being broken away to better illustrate internal structural features;
FIG. 2 is a side elevational view illustrating the mounted position of the heating apparatus;
FIG. 3 is a perspective view of the positioned heating apparatus showing further structural details thereof;
FIG. 4 is a rear elevational view illustrating the mounting support for the heating apparatus in which the heater thereof is illustrated in phantom perspective so as not to obscure structural features of the support; and
FIG. 5 is an exemplary wiring diagram for the electrical controls of the heating apparatus.
Reference is now made to the drawings, and in particular to FIGS. 2-4, illustrating the heating apparatus, generally designated 10, which is particularly advantageously used in association with an offset printing press of the type including an endless conveyor 12. As generally understood, the end or discharge portion of an offset printing press (not shown) includes the endless conveyor 12 which, in turn, is formed by opposed sidewalls 14 and 16, a front wall 18, and a top wall 20. In practice, conveyor 12 transports the printed piece of material from a printing station to the delivering pile. Conveyor 12 is conventional in construction and comprises endless chains 22 which are positioned adjacent to the respective sidewalls 14 and 16, only one such chain being illustrated in the drawings.
The chains 22 are entrained about sprocket wheels at the ends of the conveyor system to form an upper run 24 and a lower run 26. The runs 24 and 26 are maintained in spaced relation to each other by an idler sprocket wheel 28. As is conventional in systems of this type, one of the end sprocket wheels is driven by an appropriate motor to cause the lower run 26 of the chain 22 to move in the direction indicated by the arrow 30.
Extending transversely between the chains 22 and connected thereto is a plurality of longitudinally spaced bars 32, each provided with gripper fingers 34 which are adapted to grip the printed sheets of material. Specifically, as the sheets are printed, they are gripped by those fingers 34 on the bars 32 which are connected to the portion of the chains 22 forming the lower run 26. Thus, the sheets of printed material leaving the last printing station are carried upwards therefrom by the lower run 26 of the conveyor system 12 in the direction of the arrow 30 to the discharge end of the press. The rate of movement of the chains 22 cause the sheets to lie substantially within the plane of the chains.
Appropriately supported in a transverse position between the chains 22, in a manner which will now be described in detail, is the heating apparatus 10. The significant aspect of the support for the heater 10 is that it can readily make allowances for changes in size of the heater that occur due to thermal expansion and contraction thereof. Specifically, the support includes a first set of cooperating interfitting male and female support members, individually and collectively generally designated 36, advantageously located at each of the four corners of the heating apparatus 10. As illustrated, each support 36 includes a female member 38 appropriately attached, as at 40, by welding or the like to the heating apparatus 10 so as to present a through bore 42 in a substantially horizontal orientation. The male element cooperating therewith is a cylindrical element 44 which, in each case, projects into the through bore 42 from a remote clearance position located to the side of the heating apparatus 10.
In the case of the supports 36 located along the bottom edge of the heating apparatus, each laterally extending end of each cylindrical element 44 is projected within a cylindrical bore 48 and pinned, as at 46, to a mounting bracket 50 respectively mounted, as illustrated in FIG. 4, to the opposing sidewalls 14 and 16.
At the upper edge of the heating apparatus 10, each laterally extending end of an element 44 is received in the bore of a threaded member 52 threadably engaged to one leg 54 of an L-shaped bracket 56. The other leg 58 of the bracket 56 has a through bore 60 having projected therethrough an L-shaped mounting element 62 which, at its opposite end, is connected to a support wall. In the illustrated situation, the two elements 62 are respectively mounted to the sidewalls 14 and 16. Thus, the brackets 56 and elements 62 constitute a second set of cooperating male and female support members in which allowance is made for thermal expansion and contraction along vertical axes coincident with the depending vertically oriented legs 64 of the elements 62.
From the foregoing, it should be readily appreciated that the heating apparatus 10 hereof is therefore mounted between the sidewalls 14 and 16 so as to have clearance for and readily allow for changes in size of the heater 10 due to thermal expansion and contraction in either of the horizontal or vertical directions. That is, lateral or horizontal expansions or contractions are permitted, as clearly illustrated in FIG. 4, by relative sliding movement between the interfitting elements of the supports 36. Naturally, only one vertically aligned pair of the supports 36 need be operatively arranged for relative sliding movement, which pair, as illustrated in FIG. 4, will be understood to be on the left-hand side. The other pair of the supports 36 preferably are locked against sliding movement, as by set screws 66, in order to minimize inadvertent lateral shifting in the position of the heating apparatus 10 while in its mounted position on the horizontally oriented elements 44. In the above respect, it will be noted that apparatus 10, until it is locked into position, is slidably adjustable along the elements 44. Additionally, because the elements 44 and cooperating bores 42 are cylindrical, apparatus 10 also has a degree of rotative movement about the horizontal axis defined by the lower elements 44, as well as having a degree of corresponding rotative or translation movement about the horizontal axis defined by the upper elements 44.
Vertical thermal expansion or contracting movements in the apparatus 10 are, of course, allowed for by relative vertical movement of the supports or brackets along the vertical axes of the depending legs 64. Thus, clearance for both vertical and horizontal thermal expansion and contraction in the apparatus 10 is readily permitted by the respective two sets of supports 36 and 56. Additionally, the degrees of movement of said supports also facilitates providing the heating apparatus 10 with a range of operative locations between the printing press chains 22. It should also be apparent, particularly from FIG. 3, that the supports 36 enable the apparatus 10 to be at a selected slightly inclined or tilted orientation.
Turning now to the construction of the heating apparatus 10, the same has a noteworthy modular construction which will now be described in detail. Specifically, and as is perhaps best illustrated in FIGS. 1 and 3, the apparatus 10 includes a selected number of subassemblies, individually and collectively designated 68. Each assembly 68, in turn, includes a rectangular frame 70, U-shaped in cross section, which bounds an internal operative area or compartment 72. Located within each compartment 72 are plural quartz sections 74 of conventional construction, each including cooperating grooves and heating elements 76, the details of which are well understood and in any event form no part of the present invention.
Sections 74 are readily accommodated between the projection legs 78 and 80 which bound all four sides of the frame 70. The rear opening of compartment 72 is preferably closed by a three-layered closure consisting of a panel 82, preferably fabricated of a felt-type insulation, a panel 84, preferably fabricated of a blanket-type insulation, and lastly a panel 86, preferably fabricated of sheet metal. Operating in a manner which is well understood, the heating elements 76 are electrically energized by conductors 88 accommodated through the upper frame leg 89 and, in response to said energization, produce infrared radiation which passes through the quartz section 74.
The use of quartz as a construction material for each section 74 significantly contributes to providing a unit which has an optimum thinness permitting it to be readily installed in a confined area. To this end, the quartz had been advantageously machined and provided with plural grooves 75, oriented in transverse directions, in which the heating elements 76 are readily accommodated. That is, the intersecting grooves 75 delineate plural raised areas 77 about which the length of each heating element 76 is appropriately bent and shaped so as to be mountingly disposed within the protective configuration provided by the grooves 75. Thus, each section 74 consists essentially only of the thickness of the quartz material and does not require any mounting or retaining panel which would add to the thickness of the section 74.
Each assembly 68 consisting, as just noted, of quartz sections 74 and frame 70, are, in turn, mounted, in a selected number, in an appropriately sized second frame, generally designated 90. Frame 90, like frame 70, is fabricated of metal and is U-shaped in cross section so as to readily accommodate the assembly 68 between its legs 92 and 14, at least along a bottom and two opposite sides thereof. Along its remaining upper edge, frame 90 has a compartment or junction-box construction 96 to accommodate the previously noted conductors 88 of the heating elements 76. Along the bottom wall of the box 96 are upstanding hexagonal supports, individually and collectively designated 98, which serve both as stops for the assemblies 86 and also receive threaded elements 100 which, in practice, are used to mount cover plates 102 serving as closures for the box 96. Completing the construction of frame 90 are the previously noted support members 38 appropriately mounted at each of the four corners of frame 90. As a consequence of the modular construction of the heating apparatus 10, as just described, the size and extent of the heating surface thereof is a function of the number of assemblies 86 that are selected for use in the assembly of the apparatus 10.
Referring now to FIG. 2, it will be noted that the preferred mounted position of the heating apparatus 10 is such that the quartz sections 74 thereof are arranged in facing relation to a reflector 104 appropriately mounted on front wall 18. Accordingly, infrared radiation, depicted by the arrows 106, follows the path indicated, namely that which moves from the apparatus 10 against the reflector 104 and then in a reverse direction around the apparatus 10 and in heat exchange relation with the printed material being carried along the path 30 by the lower chain run 26. The intensity of heat within the heating zone is somewhat increased by a second reflector 108 located adjacent and to one side of the lower chain run 26, which confines the infrared radiation to the heating zone. Naturally, reflector 108 also is effective in preventing infrared radiations from passing beyond the heating zone and possibly creating a fire hazard.
The panels 86 containing the sections 74 are easily mounted within the frame 90 by placing the same, one at a time, between the legs 92 and 94 and beneath spring clips 110, secured to the top leg 92 along the lower portion of the frame 90. Three such spring clips are shown mounted to this top leg 92. These clips are located to overlay adjacent ones of the assemblies 68. As each assembly 68 is dropped into position in the frame 90 between the legs 92 and 94, they are restricted and retained in position by the clips 110 at the base and at their tops by the hexagonal supports 98. Thereafter, the cover plates 102 are secured in position by the application of the screws or thread elements 100.
Referring now to the exemplary circuit diagram of FIG. 5, each of the conductors 88 of the heating elements 76 includes contacts 112 of a solenoid-operated switch 114 which, as generally understood, must be operated or closed to complete the circuit connecting the three-phase resistance heating elements 76 to the power supply. The closing of switch 114, in turn, occurs when its coil 116 is energized during the operating cycles of either the startup timer 118 or the variable timer 120. During a reference time interval, timer 118 will be understood to operate only 15 percent of the time, whereas timer 120 may operate from 40 to 80 percent of the time. Thus, timer 118 is used at startup, and timer 120 is used thereafter to provide a selected, controlled heat from the heating elements 76 in accordance with the drying requirements of the printing run.
Completing the circuit of FIG. 5 is a three-way selector switch 122 having an off position, at 124, and operating positions at 126, 128 for respectively selecting either the timer 118 or 120.
From the foregoing, it should be readily appreciated that there has been described herein a heating apparatus advantageously used in an offset printing press which is compatible for use in existing printing presses and which effectively and efficiently produces a heating zone to dry and set the ink on printed sheets of material as these sheets of material pass through the heating zone.
A latitude of modification, change and substitution is intended in the foregoing disclosure and some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.
Infrared heaters are currently in common use in offset printing presses to speed up the drying of printing inks and have, for all practical purposes, replaced the use of drying powders and other such techniques. The manner of incorporating the heater as part of the press, however, has not been entirely satisfactory. For example, the extent of printing which has to be dried usually varies considerably and, for efficiency's sake, the capacity of the heater should therefore vary correspondingly so that the use of either excessive or insufficient heat is minimized. Another major problem involves mounting the heater to avoid inadvertent movement thereof during printing operation of the press and yet having adequate provision in the mounting for thermal expansion and contraction of the heater.
Additionally, heat control of the heater has been a major problem. When an excessive heat is applied, this is effective to dry the inks, but it may also cause shrinkage of the paper. An insufficient heat brings the oils or vehicle to the surface, leaving the ink still wet.
Broadly, it is an object of the present invention to provide an improved printing press heater overcoming the foregoing and other shortcomings of the prior art. Specifically, it is an object to provide a heater formed of an assembly of heating units so that the number of units selected for assembly significantly determines the effective heating surface or area thereof. Also the supports for the heater are expandable and contractable along transverse axes to thereby allow for thermal expansion and contraction of the heater.
A printing press heater demonstrating objects and advantages of the present invention includes heating units appropriately assembled in first frame members which, in a select number, are in turn mounted in a second frame, and a support for the second frame that adequately allows for thermal expansion and contraction size changes. Specifically, the support includes a first set of cooperating members having provision for relative movement, as may be occasioned by thermal expansion and contraction, along horizontal axes, and a second set of cooperating members supporting said first set which has provision for a similar allowance for expansion and contracting movements, but along vertical axes. Thus, the support allows for thermal expansion and contraction of the heater along transverse axes.
The above brief description, as well as further objects, features and advantages of the present invention, will be more fully appreciated by reference to the following detailed description of a presently preferred, but nonetheless illustrative embodiment in accordance with the present invention, when taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is an exploded perspective view of a printing press heating apparatus according to the present invention, portions thereof being broken away to better illustrate internal structural features;
FIG. 2 is a side elevational view illustrating the mounted position of the heating apparatus;
FIG. 3 is a perspective view of the positioned heating apparatus showing further structural details thereof;
FIG. 4 is a rear elevational view illustrating the mounting support for the heating apparatus in which the heater thereof is illustrated in phantom perspective so as not to obscure structural features of the support; and
FIG. 5 is an exemplary wiring diagram for the electrical controls of the heating apparatus.
Reference is now made to the drawings, and in particular to FIGS. 2-4, illustrating the heating apparatus, generally designated 10, which is particularly advantageously used in association with an offset printing press of the type including an endless conveyor 12. As generally understood, the end or discharge portion of an offset printing press (not shown) includes the endless conveyor 12 which, in turn, is formed by opposed sidewalls 14 and 16, a front wall 18, and a top wall 20. In practice, conveyor 12 transports the printed piece of material from a printing station to the delivering pile. Conveyor 12 is conventional in construction and comprises endless chains 22 which are positioned adjacent to the respective sidewalls 14 and 16, only one such chain being illustrated in the drawings.
The chains 22 are entrained about sprocket wheels at the ends of the conveyor system to form an upper run 24 and a lower run 26. The runs 24 and 26 are maintained in spaced relation to each other by an idler sprocket wheel 28. As is conventional in systems of this type, one of the end sprocket wheels is driven by an appropriate motor to cause the lower run 26 of the chain 22 to move in the direction indicated by the arrow 30.
Extending transversely between the chains 22 and connected thereto is a plurality of longitudinally spaced bars 32, each provided with gripper fingers 34 which are adapted to grip the printed sheets of material. Specifically, as the sheets are printed, they are gripped by those fingers 34 on the bars 32 which are connected to the portion of the chains 22 forming the lower run 26. Thus, the sheets of printed material leaving the last printing station are carried upwards therefrom by the lower run 26 of the conveyor system 12 in the direction of the arrow 30 to the discharge end of the press. The rate of movement of the chains 22 cause the sheets to lie substantially within the plane of the chains.
Appropriately supported in a transverse position between the chains 22, in a manner which will now be described in detail, is the heating apparatus 10. The significant aspect of the support for the heater 10 is that it can readily make allowances for changes in size of the heater that occur due to thermal expansion and contraction thereof. Specifically, the support includes a first set of cooperating interfitting male and female support members, individually and collectively generally designated 36, advantageously located at each of the four corners of the heating apparatus 10. As illustrated, each support 36 includes a female member 38 appropriately attached, as at 40, by welding or the like to the heating apparatus 10 so as to present a through bore 42 in a substantially horizontal orientation. The male element cooperating therewith is a cylindrical element 44 which, in each case, projects into the through bore 42 from a remote clearance position located to the side of the heating apparatus 10.
In the case of the supports 36 located along the bottom edge of the heating apparatus, each laterally extending end of each cylindrical element 44 is projected within a cylindrical bore 48 and pinned, as at 46, to a mounting bracket 50 respectively mounted, as illustrated in FIG. 4, to the opposing sidewalls 14 and 16.
At the upper edge of the heating apparatus 10, each laterally extending end of an element 44 is received in the bore of a threaded member 52 threadably engaged to one leg 54 of an L-shaped bracket 56. The other leg 58 of the bracket 56 has a through bore 60 having projected therethrough an L-shaped mounting element 62 which, at its opposite end, is connected to a support wall. In the illustrated situation, the two elements 62 are respectively mounted to the sidewalls 14 and 16. Thus, the brackets 56 and elements 62 constitute a second set of cooperating male and female support members in which allowance is made for thermal expansion and contraction along vertical axes coincident with the depending vertically oriented legs 64 of the elements 62.
From the foregoing, it should be readily appreciated that the heating apparatus 10 hereof is therefore mounted between the sidewalls 14 and 16 so as to have clearance for and readily allow for changes in size of the heater 10 due to thermal expansion and contraction in either of the horizontal or vertical directions. That is, lateral or horizontal expansions or contractions are permitted, as clearly illustrated in FIG. 4, by relative sliding movement between the interfitting elements of the supports 36. Naturally, only one vertically aligned pair of the supports 36 need be operatively arranged for relative sliding movement, which pair, as illustrated in FIG. 4, will be understood to be on the left-hand side. The other pair of the supports 36 preferably are locked against sliding movement, as by set screws 66, in order to minimize inadvertent lateral shifting in the position of the heating apparatus 10 while in its mounted position on the horizontally oriented elements 44. In the above respect, it will be noted that apparatus 10, until it is locked into position, is slidably adjustable along the elements 44. Additionally, because the elements 44 and cooperating bores 42 are cylindrical, apparatus 10 also has a degree of rotative movement about the horizontal axis defined by the lower elements 44, as well as having a degree of corresponding rotative or translation movement about the horizontal axis defined by the upper elements 44.
Vertical thermal expansion or contracting movements in the apparatus 10 are, of course, allowed for by relative vertical movement of the supports or brackets along the vertical axes of the depending legs 64. Thus, clearance for both vertical and horizontal thermal expansion and contraction in the apparatus 10 is readily permitted by the respective two sets of supports 36 and 56. Additionally, the degrees of movement of said supports also facilitates providing the heating apparatus 10 with a range of operative locations between the printing press chains 22. It should also be apparent, particularly from FIG. 3, that the supports 36 enable the apparatus 10 to be at a selected slightly inclined or tilted orientation.
Turning now to the construction of the heating apparatus 10, the same has a noteworthy modular construction which will now be described in detail. Specifically, and as is perhaps best illustrated in FIGS. 1 and 3, the apparatus 10 includes a selected number of subassemblies, individually and collectively designated 68. Each assembly 68, in turn, includes a rectangular frame 70, U-shaped in cross section, which bounds an internal operative area or compartment 72. Located within each compartment 72 are plural quartz sections 74 of conventional construction, each including cooperating grooves and heating elements 76, the details of which are well understood and in any event form no part of the present invention.
Sections 74 are readily accommodated between the projection legs 78 and 80 which bound all four sides of the frame 70. The rear opening of compartment 72 is preferably closed by a three-layered closure consisting of a panel 82, preferably fabricated of a felt-type insulation, a panel 84, preferably fabricated of a blanket-type insulation, and lastly a panel 86, preferably fabricated of sheet metal. Operating in a manner which is well understood, the heating elements 76 are electrically energized by conductors 88 accommodated through the upper frame leg 89 and, in response to said energization, produce infrared radiation which passes through the quartz section 74.
The use of quartz as a construction material for each section 74 significantly contributes to providing a unit which has an optimum thinness permitting it to be readily installed in a confined area. To this end, the quartz had been advantageously machined and provided with plural grooves 75, oriented in transverse directions, in which the heating elements 76 are readily accommodated. That is, the intersecting grooves 75 delineate plural raised areas 77 about which the length of each heating element 76 is appropriately bent and shaped so as to be mountingly disposed within the protective configuration provided by the grooves 75. Thus, each section 74 consists essentially only of the thickness of the quartz material and does not require any mounting or retaining panel which would add to the thickness of the section 74.
Each assembly 68 consisting, as just noted, of quartz sections 74 and frame 70, are, in turn, mounted, in a selected number, in an appropriately sized second frame, generally designated 90. Frame 90, like frame 70, is fabricated of metal and is U-shaped in cross section so as to readily accommodate the assembly 68 between its legs 92 and 14, at least along a bottom and two opposite sides thereof. Along its remaining upper edge, frame 90 has a compartment or junction-box construction 96 to accommodate the previously noted conductors 88 of the heating elements 76. Along the bottom wall of the box 96 are upstanding hexagonal supports, individually and collectively designated 98, which serve both as stops for the assemblies 86 and also receive threaded elements 100 which, in practice, are used to mount cover plates 102 serving as closures for the box 96. Completing the construction of frame 90 are the previously noted support members 38 appropriately mounted at each of the four corners of frame 90. As a consequence of the modular construction of the heating apparatus 10, as just described, the size and extent of the heating surface thereof is a function of the number of assemblies 86 that are selected for use in the assembly of the apparatus 10.
Referring now to FIG. 2, it will be noted that the preferred mounted position of the heating apparatus 10 is such that the quartz sections 74 thereof are arranged in facing relation to a reflector 104 appropriately mounted on front wall 18. Accordingly, infrared radiation, depicted by the arrows 106, follows the path indicated, namely that which moves from the apparatus 10 against the reflector 104 and then in a reverse direction around the apparatus 10 and in heat exchange relation with the printed material being carried along the path 30 by the lower chain run 26. The intensity of heat within the heating zone is somewhat increased by a second reflector 108 located adjacent and to one side of the lower chain run 26, which confines the infrared radiation to the heating zone. Naturally, reflector 108 also is effective in preventing infrared radiations from passing beyond the heating zone and possibly creating a fire hazard.
The panels 86 containing the sections 74 are easily mounted within the frame 90 by placing the same, one at a time, between the legs 92 and 94 and beneath spring clips 110, secured to the top leg 92 along the lower portion of the frame 90. Three such spring clips are shown mounted to this top leg 92. These clips are located to overlay adjacent ones of the assemblies 68. As each assembly 68 is dropped into position in the frame 90 between the legs 92 and 94, they are restricted and retained in position by the clips 110 at the base and at their tops by the hexagonal supports 98. Thereafter, the cover plates 102 are secured in position by the application of the screws or thread elements 100.
Referring now to the exemplary circuit diagram of FIG. 5, each of the conductors 88 of the heating elements 76 includes contacts 112 of a solenoid-operated switch 114 which, as generally understood, must be operated or closed to complete the circuit connecting the three-phase resistance heating elements 76 to the power supply. The closing of switch 114, in turn, occurs when its coil 116 is energized during the operating cycles of either the startup timer 118 or the variable timer 120. During a reference time interval, timer 118 will be understood to operate only 15 percent of the time, whereas timer 120 may operate from 40 to 80 percent of the time. Thus, timer 118 is used at startup, and timer 120 is used thereafter to provide a selected, controlled heat from the heating elements 76 in accordance with the drying requirements of the printing run.
Completing the circuit of FIG. 5 is a three-way selector switch 122 having an off position, at 124, and operating positions at 126, 128 for respectively selecting either the timer 118 or 120.
From the foregoing, it should be readily appreciated that there has been described herein a heating apparatus advantageously used in an offset printing press which is compatible for use in existing printing presses and which effectively and efficiently produces a heating zone to dry and set the ink on printed sheets of material as these sheets of material pass through the heating zone.
A latitude of modification, change and substitution is intended in the foregoing disclosure and some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.