Slip feed roller feeding

Abstract

A method and assembly provide a feed roller that is designed to slip when a foreign object, not designed to be fed by the feed roller, engages the feed roller. One or more rollers are mounted on a shaft and have a grooved surface spring pressed into engagement with a pin extending radially outwardly from the shaft. When a force is applied to the circumference of the roller greater than the force applied by a spring which biases the grooved surface into contact with the pin, the roller will slip, and substantially stop rotating. Since the shaft continues to be driven, if the foreign object is removed the next time the grooved surface is aligned with the pin it will be biased into engagement with the pin so that that roller automatically starts to rotate and provide a feeding action again.

Description

BACKGROUND AND SUMMARY OF THE INVENTION

[0001] There are many situations in which it is desirable to be able to feed mailing media, or like sheet material (such as documents) that are relatively thick, e.g. having a nominal thickness of at least about 0.125 inches (e.g. about 0.33 centimeters). However if such thicker media or sheet material is being fed, it is possible that a foreign object can be jammed into association with a feed roller; for example an operator's finger or piece of clothing, or hair, or a pencil or pen, might be jammed into contact with a feed roller. If the feed roller continues to be driven then the feed roller or shaft may break, or other components of the equipment with which the feed roller is associated can be mangled, or the clothing or safety of the operator may be adversely affected.

[0002] According to the present invention a media moving assembly, and a method of feeding mailing media or other sheet material, are provided which overcome the problem identified above. The invention is applicable to a wide variety of equipment, including addressing printers such as disclosed in U.S. Pat. Nos. 5,163,669 and 5,401,013 (the disclosures of which are hereby incorporated by reference herein), but the invention is not restricted to addressing printers, but can be utilized in many other different types of conventional equipment in which a sheet is being automatically fed by a feed roller system.

[0003] According to the most basic concept of the present invention, one or a plurality of rollers is or are mounted on a driven shaft in such a way that if a foreign object engages a roller the roller slips on the shaft while the shaft continues to rotate. The slipping action is entirely automatic. Also it is preferred according to the invention that once the foreign object is removed that the roller automatically will continue to be driven by the shaft.

[0004] According to the invention this basic functionality is accomplished in a very simple and inexpensive manner utilizing one or more pins which extend radially through the shaft and are engaged by grooved surfaces operatively connected to (e.g. fixed to) one or more rollers, with a spring biasing each grooved surface into contact with a pin. Where the biasing force of the spring is overcome by an object engaging the peripheral surface of the roller to retard its rotation, the pin will be disengaged from the grooved surface so that the roller remains stationary while the shaft continues to rotate.

[0005] According to one aspect of the present invention there is provided a media moving assembly comprising: A shaft. A roller mounted on the shaft. A pin extending radially outwardly from the shaft. A grooved surface operatively connected to the roller. And, a spring which biases the roller grooved surface into contact with the pin, so that the pin and grooved surface provide a slip connection between the roller and shaft.

[0006] The spring may comprise a coil spring surrounding the shaft, and the pin may be substantially circular in cross-section and the groove substantially V-shaped, although other configurations of pins and grooves may be provided.

[0007] Normally the roller comprises a first roller having a first grooved surface operatively connected thereto (e.g. fixed thereto, although the engagement may just be an abutting engagement with the grooved surface and roller maintained in contact by the spring bias), and the pin comprises a first pin. In this case there also is at least a second roller on the shaft and a second pin extending radially outwardly from the shaft, and a second grooved surface operatively associated with the second roller spring biased into engagement with the second pin. A single coil spring may be provided surrounding the shaft and extending between the first and second rollers and simultaneously biasing the first and second rollers toward engagement with the first and second pins, respectively. First and second washers may be provided between the coil spring and the first and second rollers. The assembly may also comprise a plurality of additional rollers mounted on the shaft, and a plurality of additional pins, and at least some of the additional plurality of rollers having a grooved surface spring biased into engagement with a pin.

[0008] While a wide variety of different types of rollers may be utilized, the rollers may comprise a hard plastic body roller having a resilient material circumferential covering, as is common in feed rollers associated with mailing media printers. The shaft may be mounted in a mailing media printer, or other type of printer, and the assembly may further comprise means for rotating the shaft so that the rollers on the shaft engage media in a stack to feed the media from the stack into the printer. The means for rotating the shaft may be a motor, a gear train, or chain and sprocket assembly, belt and pulley assembly, or any other conventional structure for that purpose. The invention is ideally suited for address printers such as shown in U.S. Pat. Nos. 5,163,669 and 5,401,013 with the rollers associated with a stack of mailing media or other sheet material and feeding the media one at a time from the bottom of the stack into the address printer.

[0009] Each pin preferably has a portion thereof on each side of the shaft, and each grooved surface has a groove on each side of the shaft, so that two portions of each pin engage two grooves of the grooved surface. Alternatively more than two pin portions may extend radially outward from the shaft and the grooved surface may have more than two grooves; or one pin portion and one groove may be provided. Where two pin portions and two grooves are provided preferably a single pin extends radially through the shaft to define portions on either side of the shaft, although alternatively the pin portions may be welded to, molded with, or otherwise affixed to the shaft and simply extend outwardly from the peripheral surface thereof.

[0010] According to another aspect of the present invention there is provided a method of feeding mailing media having a normal thickness of at least about 0.125 inches, comprising: (a) Engaging the mailing media having a normal thickness of at least about 0.125 inches with a plurality of drive rollers rotating with a common shaft to move the media in a first direction. And, (b) if one or more of the rollers engage a foreign object, causing the one or more rollers engaging the foreign object to automatically substantially stop rotating while rollers not operatively engaging the foreign object continue to rotate.

[0011] The method as set forth above may further comprise (c) when engagement of the foreign object with the one or more rollers is terminated, automatically causing those one or more rollers to continue rotating and engaging and moving the mailing media. For example (a) through (c) may be practiced using a shaft having a plurality of pins extending radially outwardly from the shaft, and a grooved surface operatively connected to each roller having the grooved surface thereof engaging one of the pins, and a spring which biases each roller grooved surface into contact with a pin. In many circumstances (a) is practiced to move the mailing media from a stack in a first direction away from the stack. For example (a) may be further practiced to engage and move the bottom of the lowest mailing media in the stack.

[0012] According to another aspect of the present invention there is provided a method of feeding sheet material, comprising: (a) Engaging the sheet material with a plurality of drive rollers on a common shaft to move the sheet material in a first direction. (b) If one or more of the rollers engage a foreign object, causing the one or more rollers engaging the foreign object to automatically substantially stop rotating while rollers not operatively engaging the foreign object continue to rotate. And, (c) when engagement of the foreign object with the one or more rollers is terminated, automatically causing those one or more rollers to continue to rotate, engaging and moving the sheet material. The details of the practice of procedures (a) through (c) may be as set forth above.

[0013] It is the primary object of the present invention to provide a simple and effective slip feed roller assembly and method of utilization thereof to minimize damage to feed roller assemblies, and enhance the safety and integrity of persons or implements around the feed roller assembly. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a side schematic view of an exemplary feed roller assembly according to the present invention, with the roller and spring shown in longitudinal cross-section and the shaft shown in elevation;

[0015] FIG. 2 is a side view of the assembly of FIG. 1 showing the roller engaging the lowest piece of mailing media in a stack and feeding it in a given direction;

[0016] FIG. 3 is a side detail view of an exemplary roller according to the invention showing a slipped condition between the shaft pin and roller grooved surface, in which position the rotating shaft will not drive the roller;

[0017] FIG. 4 is a side detail view of the roller when in the position of FIG. 3, with the roller and spring shown in cross-section and the shaft, pin, and grooved surface in elevation; and

[0018] FIG. 5 is a schematic detail view showing an exemplary pin resting in an exemplary groove in a roller system according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0019] An exemplary roller assembly according to the present invention is shown generally by reference numeral 10 in FIG. 1. It includes a shaft 11 and a plurality of rollers 12 mounted on the shaft. The shaft 11 is rotated by a suitable rotating means, shown schematically in FIG. 1 as a motor 13. However the shaft 11 can be rotated by any conventional rotating means such as gears, belts and pulleys, sprockets and chains, etc.

[0020] The shaft 11 and the rollers 12 as illustrated in FIG. 1 are of the type that is typically used in a feed roll assembly for an addressing printer, such as shown in U.S. Pat. No. 5,401,013. However it is to be understood that other types of shafts and rollers may be provided. In the embodiment illustrated in FIGS. 1 and 2, the shaft 11 is preferably of metal or hard plastic, while each of the rollers 12 comprises a central tubular portion 13 having an internal diameter slightly greater than the external diameter of the shaft 11 and not keyed to the shaft, a radially extending disc or arms 14, a peripheral tubular element 15, and a circumferential covering 16. The components 13 through 15 are preferably integrally molded from hard plastic while the circumferential covering 16 is of a resilient material, such as synthetic or natural rubber.

[0021] In one specific exemplary, but non-limiting, embodiment of the invention, for use in a printer such as in U.S. Pat. No. 5,401,013, the rollers 12 have an outside diameter of about 2.4-2.8 inches (e.g. 2.6 inches), the hub or body (formed by elements 13-15) is of nylon with about 20-40% (e.g. about 30%) glass bead fill, the covering 16 is Nitrile rubber having a durometer of about 10-30 (e.g. about 20) Shore A, and the shaft 11 is 4150 high carbon steel.

[0022] FIG. 2 schematically illustrates one exemplary use of the feed roller assembly of FIG. 1, in association with an address printer such as shown in U.S. Pat. Nos. 5,163,669 or 5,401,013. Shown in dotted line at 20 is an element that is adapted to define a gap 21 between it and the circumferences 16 of the rollers 12 so as to accept mailing media 22, or like sheet material (such as documents), having a given thickness 23 therebetween. The element 20 may be any conventional element such as another roller, a segmented or continuous flat or curved surface, or a wide variety of other conventional components.

[0023] In the typical use of the feed roller assembly 10 the motor 13 drives the shaft 11 so that the roller 12 rotates in the direction 24 seen in FIG. 2, and each mailing media 22 (such as a stuffed envelope) has the under surface 25 thereof engaged by the circumference 16 of some or all of the rollers 12 to drive the media 22 in the direction 26 through the gap 21. The next sheet 22 then automatically comes into contact with the rotating rollers 12, to be driven next through the gap 21 in the direction 26. The direction 26 typically leads to a printer or other sheet handling equipment.

[0024] Especially if media 22 having a thickness 23 of about 0.125 inches (about 0.33 centimeters) or more is to be handled, which requires an appropriate adjustment between the element 20 and the rollers 12 (as in U.S. Pat. No. 5,401,013), there is a danger that a foreign object, such as hair, a finger, a piece of clothing, a pen or pencil, a paper clip, or the like, could engage one or more of the rollers 12, and perhaps become wedged in the gap 21. This could have a number of adverse affects including breaking or otherwise harming one or more of the rollers 12, breaking a drive component for driving the shaft 11, causing other damage to the equipment, causing damage to the foreign object, and/or presenting a safety hazard to the operator, especially if the operator's clothing, hair, or finger is the foreign object.

[0025] In order to avoid the problems set forth above, in a very simple yet effective manner according to the invention a slip arrangement is provided between at least some of the rollers 12 (preferably all of the rollers 12) and the shaft 11 so that if a roller 12 should be engaged by a foreign object so that its rotation in the direction 24 is arrested, the roller 12 will stop while the shaft 11 continues to rotate, with substantially no damage or harm either to the equipment or the foreign object.

[0026] The simple slip connection according to the present invention preferably comprises, associated with each roller, a pin 30 which is connected to and rotatable with the shaft 11, and a grooved surface element 31 which is operatively connected to the roller 12. Preferably the grooved surface element 31 is affixed to the roller 12, although it may simply be spring pressed into contact therewith, and the element 31 keyed to the roller 12 in some manner (such as to the inner tubular portion 13 thereof). A spring, such as a coil spring 32 illustrated in FIGS. 1 and 4, biases the grooved surface element 31 into contact with the pin 30 so that normally the roller 12 rotates with the shaft 11. However should the force engaging the roller 12 and arresting its rotation be larger than the force applied by the spring 32, then the pin 30 will pop out of the grooved surface of the element 31 and the shaft 11 will continue to rotate while the roller 12 does not. For the specific exemplary, but non-limiting, embodiment of the rollers 12 and shaft 11 described above, the spring 32 could have a rate between about 30-32 lbs./in. (e.g. about 31.1 lbs./in.) and an installed force between rollers 12 of about 10-12 pounds (e.g. about 11 pounds).

[0027] One preferred embodiment of the pin 30 and the grooved surface element 31 is best illustrated in FIGS. 3 through 5. FIGS. 3 and 4 show the components 30, 31 in a non-driving condition where the force on the roller 12 was greater than the spring force of the spring 30 so that the pin 30 popped out of the groove or grooves 33 in the surface 34 of the grooved surface element 31. As seen in FIGS. 3 and 4 the pin 30 has first and second portions 35, 36, thereof that extend radially outwardly from the shaft 11. While the portions 35, 36 may be integrally molded with the shaft 11, or welded or otherwise affixed to the exterior surface thereof, in the preferred embodiment the pin 30 simply is long enough to extend completely through the shaft 11 and have an interference fit therewith, with the portions 35, 36 extending radially outwardly from the shaft 11 approximately equal distances on opposite sides of the shaft 11. For example, the pin 30 could be a hardened steel dowel pin.

[0028] In the embodiment of FIGS. 3 and 4 preferably two grooves 33 are provided in the grooved surface 34, one on each side of the shaft 11, and for one groove 33 for cooperation with each pin portion 35, 36. However more grooves 33 than pin portions 35, 36 may be provided. While two pin portions 35, 36 and two grooves 33 are preferred, more of each may be provided.

[0029] In the embodiment illustrated in FIGS. 3 through 5 the pin portions 35, 36 are preferably circular in cross section (as most clearly seen in FIG. 5) while the grooves 33 are substantially V-shaped in cross-section, and the components dimensioned so that pin portions 35 will sit in the grooves 33 as illustrated in FIG. 5 when pressed by the springs 32. However other shapes may be provided for both the pin 30 and the grooves 33. For example the pin portions 35, 36 could have polygonal shapes in cross-section, while the grooves 33 could be rounded, have multiple surfaces (for example corresponding to multiple surfaces on polygonal shaped pin portions 35, 36), or the like.

[0030] In the preferred embodiment illustrated in the drawings (particularly see FIGS. 1 and 4) the spring 32 for biasing comprises a coil spring 32 that surrounds the shaft 11 and acts between two rollers 12, biasing them away from each other and with the grooved surface element 31 thereof into contact with pins 30. Preferably each spring 32 engages a washer 38 (see FIG. 4) at each end thereof to ensure optimum operability.

[0031] In the method according to the present invention utilizing the assembly 10, mailing media 22, or like sheet material, having a nominal thickness of at least about 0.125 inches is engaged with a plurality of drive rollers 12 on a common shaft 11, to move the media in the first direction 26. If one or more of the rollers 12 engage a foreign object, causing the one or more rollers 12 engaging the foreign object to automatically substantially stop rotating while rollers 12 not operatively engaging (that is not effectively stopped by) the foreign object continue to rotate in direction 24. The method also preferably comprises, when engagement of the foreign object with one or more rollers is terminated, automatically causing those one or more rollers 12 to continue rotating, and engaging and moving the mailing media 22. This is effected since with the pin 30 and grooved surface element 31 in the position illustrated in FIGS. 3 and 4, when the object is removed from engagement with the roller 12 when the shaft 11 rotates to the position where the pin portions 35, 36 are aligned with the grooves 33, the biasing force of the spring 32 will now cause the grooves 33 to be pressed into engagement with the pin portions 35, 36, which then again results in rotation of the roller 12 in the direction 24 and thus moving of the media 22 in the direction 26. The shaft 11 continues to rotate, during the practice of the method, and substantially no damage to any component of the assembly 10 or associated printer or other device, nor to the foreign object, results.

[0032] It will thus be seen that according to the present invention a simple yet effective method and apparatus are provided for minimizing damage to machine components, or foreign objects, during automatic feeding of mailing media or other sheet material to a utilization device such as a printer. While the invention has been herein shown and described in what is presently conceived to be the most practical and preferred embodiment thereof it will be apparent to those of ordinary skill in the art that many modifications may be made thereof within the scope of the invention, which scope is to be accorded the broadest interpretation of the appended claims so as to encompass all equivalent assemblies and methods.

Claims

1. A method of feeding mailing media having a normal thickness of at least about 0.125 inches, comprising: (a) engaging the mailing media having a normal thickness of at least about 0.125 inches with a plurality of drive rollers on a common shaft to move the media in a first direction; and (b) if one or more of the rollers engage a foreign object, causing the one or more rollers engaging the foreign object to automatically substantially stop rotating while rollers not engaging the foreign object continue to rotate.

2. A method as recited in claim 1 further comprising (c) when engagement of the foreign object with the one or more rollers is terminated, automatically causing those one or more rollers to continue rotating, engaging and moving the mailing media.

3. A method as recited in claim 2 wherein (a)-(c) are practiced using a shaft having a plurality of pins extending radially outwardly from the shaft, and a grooved surface operatively connected to each roller having the grooved surface thereof engaging one of the pins, and a spring which biases each roller grooved surface into contact with a pin.

4. A method as recited in claim 1 wherein (a) is practiced to move the mailing media from a stack in a first direction away from the stack.

5. A method as recited in claim 4 wherein (a) is further practiced to engage and move the bottom of the lowest mailing media in the stack.

6. A method as recited in claim 2 wherein (a) is practiced to move the mailing media from a stack in a first direction away from the stack.

7. A method as recited in claim 6 wherein (a) is further practiced to engage and move the bottom of the lowest mailing media in the stack.

8. A method of feeding sheet material, comprising: (a) engaging the sheet material with a plurality of drive rollers on a common shaft to move the sheet material in a first direction; (b) if one or more of the rollers engage a foreign object, causing the one or more rollers engaging the foreign object to automatically substantially stop rotating while rollers not engaging the foreign object continue to rotate; and (c) when engagement of the foreign object with the one or more rollers is terminated, automatically causing those one or more rollers to continue rotating, engaging and moving the sheet material.

9. A method as recited in claim 8 wherein (a)-(c) are practiced using a shaft having a plurality of pins extending radially outwardly from the shaft, and a grooved surface operatively connected to each roller having the grooved surface thereof engaging one of the pins, and a spring which biases each roller grooved surface into contact with a pin.

10. A method as recited in claim 8 wherein (a) is practiced to move the sheet material from a stack in a first direction away from the stack.

11. A method as recited in claim 10 wherein (a) is further practiced to engage and move the bottom of the lowest sheet of sheet material in the stack.

12. A media moving assembly comprising: a shaft; a roller mounted on said shaft; a pin extending radially outwardly from said shaft; a grooved surface operatively connected to said roller; and a spring which biases said roller grooved surface into contact with said pin, so that said pin and grooved surface provide a slip connection between said roller and shaft.

13. An assembly as recited in claim 12 wherein said spring comprises a coil spring surrounding said shaft.

14. An assembly as recited in claim 12 wherein said pin is substantially circular in cross-section and said groove is substantially V-shaped.

15. An assembly as recited in claim 12 wherein said roller comprises a first roller having a first grooved surface operatively connected thereto, and said pin comprises a first pin; and further comprising at least a second roller on said shaft, and a second pin extending radially outwardly from said shaft, a second grooved surface operatively associated with said second roller spring biased into engagement with said second pin.

16. An assembly as recited in claim 15 wherein a single coil spring surrounding said shaft extends between said first and second rollers and simultaneously biases said first and second rollers toward engagement with said first and second pins.

17. An assembly as recited in claim 16 further comprising first and second washers between said coil spring and said first and second rollers.

18. An assembly as recited in claim 16 wherein said spring has a rate of between about 30-32 pounds/inch and an installed force of between about 10-12 pounds, and said rollers have an outside diameter of between about 2.4-2.8 inches.

19. An assembly as recited in claim 18 wherein each of said pins is substantially circular in cross-section and each of said grooves is substantially V-shaped, and each of said pins has a portion thereof on each side of said shaft and each of said grooved surfaces has a groove on each side of said shaft, so that two portions of each pin engage two grooves of said grooved surface.

20. An assembly as recited in claim 12 wherein said grooved surface is fixed to said roller.

21. An assembly as recited in claim 15 further comprising a plurality of additional rollers mounted on said shaft, and a plurality of additional pins, and at least some of said additional plurality of rollers having a grooved surface spring biased into engagement with a pin.

22. An assembly as recited in claim 21 wherein said shaft is mounted in a printer; and further comprising means for rotating said shaft so that said rollers on said shaft engage media in a stack to feed the media from the stack into said printer.

23. An assembly as recited in claim 12 wherein said roller comprises a hard plastic body roller having a resilient material circumferential covering.

24. An assembly as recited in claim 14 wherein said grooved surface is fixed to said roller; and wherein said pin extends through said shaft and has a portion thereof on each side of said shaft and said grooved surface has a groove on each side of said shaft, so that two portions of each pin engage two grooves of said grooved surface.

25. An assembly as recited in claim 23 wherein said roller body comprises nylon with between about 20-40% glass bead fill, and said resilient material is Nitrile rubber having a durometer of between about 10-30 Shore A.