RIBBON SPOOL
United States Patent 3623586
A clamping device for securing and maintaining in position the leader of a ribbon or the like in a tubular spool wherein the clamping action is derived from the interengagement of a core and a plurality of camming surfaces in the spool, the core being freely rotatable within the spool. The spool has, formed in its wall, a longitudinal slot for receiving the ribbon leader, and an adjacent indent portion adapted to cam the core against an inside surface of the spool and also against the indent portion for the length of the leader. The leader is held between the camming surfaces of the spool and the core by reason of the pulling forces on the leader as the spool is rotated, there also being additional slots in the spool cooperating with spacers for initiating release of the ribbon from the spool.
US Patent References:
/1183819.html
Keiser - May 1916 - 1183819
Spindle for engaging and winding textile fabric
Coker - May 1930 - 1759095
Ribbon reel
Wallace - December 1937 - 2102446
Hub construction for a film spool
Tucker - November 1939 - 2180023
Apparatus for clamping flexible material on cylinders
Houston - March 1953 - 2631349
/1183819.html
Keiser - May 1916 - 1183819
Spindle for engaging and winding textile fabric
Coker - May 1930 - 1759095
Ribbon reel
Wallace - December 1937 - 2102446
Hub construction for a film spool
Tucker - November 1939 - 2180023
Apparatus for clamping flexible material on cylinders
Houston - March 1953 - 2631349
Application Number:
04/853348
Publication Date:
11/30/1971
Filing Date:
08/27/1969
View Patent Images:
Export Citation:
Assignee:
The National Cash Register Company (Dayton, OH)
Primary Class:
Other Classes:
400/238, 242/586.500
International Classes:
B41J33/00; B41J35/00; B65H75/28
Field of Search:
197/175,172,151 242/74.1,74 24/255
US Patent References:
Primary Examiner:
Pulfrey, Robert E.
Assistant Examiner:
Pellegrino, Stephen C.
Claims:
What is claimed is
1. A clamping device for securing and releasing one end of a ribbon or the like in the winding and unwinding thereof, comprising
2. The device of claim 1 wherein the tubular member lip portion is formed to provide a surface inwardly from the circumference of the tubular member.
3. The device of claim 1 wherein the core member includes a surface along its length defined by a chordal portion omitted from said member.
4. The device of claim 1 wherein the core member includes abutment means movable in the opening extensions along the predetermined distance around the periphery of the tubular member to rotate the core member and thus release the hold on the ribbon.
5. Means for securing one end of a ribbon in a hollow spool having a longitudinal slot of limited length therein, said means including
6. The securing means of claim 5 wherein said core member includes a surface along its length of lesser dimension than that of the radius of the core to form edge portions engageable with the spool portion and with the interior surface of the spool as said core is rotated in one direction.
7. The securing means of claim 5 wherein the means connected to the core member are abutments movable a predetermined distance in the slot extensions formed on the spool to rotate the core for releasing the ribbon.
8. In a printer mechanism, the combination of a type drum, a print hammer, a ribbon traveling from one spool in a path between the hammer and the type drum, and means for securing the end of the ribbon to a second spool and for releasing therefrom, said means comprising
9. The mechanism of claim 8 wherein the ribbon includes a leader attached thereto insertable along the length of the slot and around the core member to be secured to the mandrel upon rotation of the core member on its axis.
10. The mechanism of claim 8 wherein said core member abutment means are movable along the slot extensions in a path within the periphery of the mandrel.
11. In a printer, the combination of a type drum, a print hammer, record material moving in a path between the type drum and the print hammer, a ribbon travelling from a supply spool in a path adjacent the record material, and means for securing one end of the ribbon, comprising
12. The combination of claim 11 wherein said core member includes abutments fixed to its lesser dimensioned surface and movable along the slot extensions in the cylinder for release of the ribbon from the camming edges.
1. A clamping device for securing and releasing one end of a ribbon or the like in the winding and unwinding thereof, comprising
2. The device of claim 1 wherein the tubular member lip portion is formed to provide a surface inwardly from the circumference of the tubular member.
3. The device of claim 1 wherein the core member includes a surface along its length defined by a chordal portion omitted from said member.
4. The device of claim 1 wherein the core member includes abutment means movable in the opening extensions along the predetermined distance around the periphery of the tubular member to rotate the core member and thus release the hold on the ribbon.
5. Means for securing one end of a ribbon in a hollow spool having a longitudinal slot of limited length therein, said means including
6. The securing means of claim 5 wherein said core member includes a surface along its length of lesser dimension than that of the radius of the core to form edge portions engageable with the spool portion and with the interior surface of the spool as said core is rotated in one direction.
7. The securing means of claim 5 wherein the means connected to the core member are abutments movable a predetermined distance in the slot extensions formed on the spool to rotate the core for releasing the ribbon.
8. In a printer mechanism, the combination of a type drum, a print hammer, a ribbon traveling from one spool in a path between the hammer and the type drum, and means for securing the end of the ribbon to a second spool and for releasing therefrom, said means comprising
9. The mechanism of claim 8 wherein the ribbon includes a leader attached thereto insertable along the length of the slot and around the core member to be secured to the mandrel upon rotation of the core member on its axis.
10. The mechanism of claim 8 wherein said core member abutment means are movable along the slot extensions in a path within the periphery of the mandrel.
11. In a printer, the combination of a type drum, a print hammer, record material moving in a path between the type drum and the print hammer, a ribbon travelling from a supply spool in a path adjacent the record material, and means for securing one end of the ribbon, comprising
12. The combination of claim 11 wherein said core member includes abutments fixed to its lesser dimensioned surface and movable along the slot extensions in the cylinder for release of the ribbon from the camming edges.
Description:
BACKGROUND OF THE INVENTION
In the art of attaching the end of a ribbon, web, cloth, film, or the like to a spool or a reel, there have been numerous ways and means for providing gripping engagement of the end of the ribbon with the spool. The prior art shows the use of two tubes, one insertable within the other, the outer tube having a longitudinal slot and the inner tube having an external rib extending through the slot for engaging the fabric along one edge of the slot to hold one end of the fabric, as shown in U.S. Pat. No. 1,183,819, issued May 16, 1916, on the application of Jan Keiser. U.S. Pat. No. 1,759,095, issued May 20, 1930, on the application of Charles W. Coker, shows an inner tube and a resilient, split outer tube wherein the fabric is inserted and held by the wrapping force as a spindle is turned. U.S. Pat. No. 2,390,894, issued Dec. 11, 1945, on the application of John F. Morse, shows a film spool having a central core member with an opening through which the film is inserted, the core member being eccentric on its inner surface, and a rotatable clamp having an enlargement engageable with the core member eccentric surface to lock the film in place. The core member rotates on the central axis of the spool in the clamping and unclamping action. Additionally, U.S. Pat. No. 3,333,309, issued Aug. 1, 1967, on the application of Nikolai H. K. Wistinghausen, shows a core clamp of resilient material, apertured to enable springing action, and having irregularly defined inner faces for locking a roll on a square shaft.
Although the above-noted U.S. patents teach the use of the various attaching, clamping, or fastening structures for the purposes intended, said structures are limited in application and operation. For instance, the success of U.S. Pat. No. 1,759,095 must depend upon the resiliency of the outer tube to press the fabric against the inner tube, and the result in U.S. Pat. No. 2,390,894 must depend upon a fixed axis clamp device contacting an eccentric surface on the interior of the core member. However, it is desirable that a clamping device be made available for securing a ribbon leader or the like on a spool wherein the clamping action is insured by the pull of the ribbon in rotating a movable-center core about the inside of the spool, and also wherein the device is adapted for ease of loading and unloading the ribbon and so constructed as not to interfere with the winding of the ribbon on the spool.
SUMMARY OF THE INVENTION
The present invention relates to ribbon-carrying spools and more particularly to means for locking and unlocking the end of the ribbon as the ribbon is wound on and unwound from the spool. The invention is particularly useful in the field of printers wherein a carbon ribbon is caused to be driven past a type line in continuous fashion, the ribbon traveling from one spool to another (for example, from a supply spool to a takeup spool). The ribbon supply spool is characterized by having a given quantity of ribbon wound thereon and placed on a printer in position so that, when the ribbon is unwound from the supply spool, it is carried in a path around a type drum and onto a takeup spool. The takeup spool includes a hollow metallic tube or mandrel, formed with a longitudinal opening or slot along a peripheral midsection thereof, and a core member inserted inside the mandrel, the core member being adapted to cooperate with the opening in the mandrel to receive the end of the ribbon and to secure it during winding of the ribbon onto the spool. The ribbon generally has a leader at one end thereof to be received into the opening and to be wound around the core in the space between the periphery of the core and the inside surface of the mandrel. The core member is of a diameter to be readily slidable inside the tube and also allow space for the ribbon leader to be wound for securing it. The core includes a pair of spacers or jutting elements fixed thereto near its ends, and positioned to ride along a predetermined angular distance in slots normal to the longitudinal opening formed in the mandrel. The longitudinal opening and the slot at either end thereof constitute a wide-based U-shaped construction for the ribbon leader to be received and for the spacers to travel when releasing the leader from the spool. The mandrel has a lip portion between the end slots, running adjacent and parallel to the longitudinal opening, and formed inwardly to decrease the diameter of the mandrel along a prescribed arc of the circle. The core is shaped to have a flattened surface cooperating with the mandrel portion, so that, upon rotation of the core to secure the leader, one edge of the surface is cammed against the lip portion, and, at the same time, the opposite edge of the flattened surface is cammed against an additional interior surface portion of the mandrel. The leader is thus secured around the core by the camming action in the two places by reason of the leader extending substantially around the core, and the ribbon is held in position as the mandrel is rotated.
As the mandrel is turned or rotated in one direction, the outward pull on the ribbon causes the core to rotate and the spacers to move along the end slots, the core entering into a wedged position along each of its edge surfaces, which clamps the ribbon leader along its length. As more force is applied on the leader, the more secure it becomes by reason of the wedging action. Rotation of the core in the opposite direction, by manual movement of the spacers along the slots, unlocks the edge surfaces of the core from the camming, or wedging, position and releases the ribbon leader for removal from the mandrel. With the leader inserted through the opening and guided around the core, the ribbon is securely clamped to the mandrel, and, the greater the pull exerted on the ribbon, the greater the clamping action between the core and the mandrel. Since the core includes a flattened surface on one side, it is free to rotate within the spool a certain distance and to seek the most effective clamping position by reason of its movable axis. In this respect, the center of the core is independent from the center of the spool.
In view of the above discussion, the principal object of the present invention is to provide locking means for securing the end of a ribbon on a spool, including a member adaptable for seeking its maximum clamping position.
An additional object of the present invention is to provide a spool having locking and unlocking features for ease in handling the end of the ribbon.
A further object of the present invention is to provide a ribbon spool with a clamping device which is self-contained within the spool for enabling winding of the ribbon thereon and unwinding the ribbon therefrom without the use of external tools.
Another object of the present invention is to provide locking and unlocking means in a ribbon spool which does not interfere with the winding and unwinding of the ribbon.
Additional advantages and features of the present invention will become apparent and fully understood from a reading of the following description taken together with the annexed drawing, in which:
FIG. 1 is a side view, in diagrammatic form, of a portion of a printer incorporating the present invention;
FIG. 2 is a perspective view of a takeup spool with the ribbon leader secured thereto; and
FIG. 3 is a view taken on the line 3--3 of FIG. 2.
Referring to FIG. 1, there is shown a portion of a printing mechanism including a type drum 12 rotatably carried by means of a shaft 14 connected to a suitable drive means (not shown). A carbon ribbon 16 is caused to be driven in a path past a type line during its travel from a supply spool 18 to a takeup spool 20. Record material 22, such as paper or the like, is likewise caused to be driven past a type hammer 24, so that, upon receipt of the signal to print, the hammer is driven against the paper, the carbon ribbon, and, in turn, a type element on the type drum 12, the result of which is an imprint of the selected type element on the paper. During printing operations, the paper and the ribbon are continuously driven past the type line, so that the ribbon 16 unwinds from the supply spool and winds around the takeup spool, it being necessary, of course, that the ribbon remain substantially taut at all times. In traveling along its path from one spool to the other, the ribbon is guided past an antiskew member 26, around rollers 28 and 30, and across a type drum protective cover 32.
Generally, the ribbon, as it comes from the manufacturer, includes a leader 36 (FIG. 2), which is provided on one end of the ribbon for the purpose of readily attaching the ribbon to the takeup spool, this spool being a tubular member made of plated steel. The leader is usually made of material sufficiently flexible to easily conform to the shape of the takeup spool, yet sufficiently rigid to provide securing and clamping capability. In this respect, the ribbon leader may be paper, cardboard, plastic, cloth, or the like which is readily securable to the ribbon by suitable means. The supply spool 18 is placed on mandrel chucks (not shown) spaced approximately the length of the spool, one of the chucks being spring loaded for ease of installation and to maintain pressure axially on the spool. Of course, the positions of the spools may be reversed from those shown in FIG. 1; that is, the upper spool may be used as the supply spool and the lower as the takeup spool, if the operation is more suitable in this manner.
The leader 36 is unwound from the supply spool 18 and threaded in a path around the type drum 12 and inserted into a longitudinal slot 38 (FIG. 2), which is longer than the width of the leader, and then around a plastic core member 40 (see also FIG. 1) previously placed within the spool 20. As seen in FIGS. 2 and 3, the spool 20 has, formed in its periphery, a portion adjacent the slot 38, which portion includes an inwardly directed formation 42 and an outwardly directed lip 44, the lip 44 stopping short of the exterior surface of the spool. The core member 40 is circular in shape and of lesser diameter than the inside diameter of the spool to rotate freely therein, and it has a flat surface 46 along one side thereof, defined by a chordal portion removed therefrom. A pair of spacers, detents, or abutments 48 and 49 are secured to the flat surface 46 by means of screws 50 and 51, there being a spacer provided adjacent each end of the core 40 and extending into extensions 52 and 54 of the slot 38, these extensions being so positioned as to form end slots for a predetermined distance around the circumference of the spool 20. As the core 40 is adaptable to be rotated within the spool 20, the spacers 48 and 49 are movable freely along the slot extensions 52 and 54, it being noted that the spacers with the securing screws are likewise within the extent of the outside diameter of the spool 20 to allow the ribbon to wrap around the spool without interference from the screws. The extent of the spacers and the screws adds sufficient diameter to the core member 40 so that the spacers are assembled to the core member after the core has been inserted into the spool from one end thereof. This extent of the spacers also insures that the core 40 will not inadvertently slide along the area of the slot 38 or out of range of the slot extensions 52 and 54, so as to permit uncontrolled movement in the clamping and releasing action thereof within the spool 20.
As mentioned above, the leader 36 is inserted through the slot 38 and threaded around the core member 48, the free end 60 of the leader passing an edge 61 of the surface 46 on its lower side (FIG. 3). In the securing, or clamping, position of the leader, a second edge 62 of the core surface 46 is against the leader and presses it into contact with the interior surface of the formation 42. In this respect, the leader 36 is firmly secured and clamped by the camming action at the core edge 61 pressing the leader against the interior surface of the spool 20 and at the core edge 62 pressing the ribbon against the spool formation 42. Looking at FIG. 3, when pull is exerted on the leader 36, the core member 40 is rotated clockwise, which cam the two edges 61 and 62 with the interior surface and the formation of the spool. The greater the pull on the leader, the greater the clamping action. This clamping action is accomplished by reason of the core member's being independent of the axis of the spool as the core seeks its own center in the clamping position. As the spool is rotated on the mandrel chucks, the leader and the ribbon are wound on the spool in circular manner, the lip portion 44 and the screws 50 and 51 being within the periphery of the spool and completely covered during winding and unwinding of the ribbon.
When the ribbon is unwound from the spool, the leader again takes the position shown in FIG. 3, so that it is still taut around the core member 40. The leader is very easily released from the clamping action of the core 40 by moving the spacers 48 and 49 counterclockwise along the slot extensions 52 and 54, which movement rotates the core away from the spool clamping surfaces to permit the leader to be pulled from around the core and out through the slot 38. Since the spacers are beyond the edges of the leader (FIG. 2), it is a simple matter to manually so turn the core thereby for releasing the ribbon from the spool.
It is thus seen that herein shown and described is a holding or clamping device for a ribbon leader which device accomplishes all the features and advantages mentioned above. While only one embodiment has been disclosed, certain variations on the above may occur to those skilled in the art, so it is contemplated that all such variations having these features are within the scope of the invention.
In the art of attaching the end of a ribbon, web, cloth, film, or the like to a spool or a reel, there have been numerous ways and means for providing gripping engagement of the end of the ribbon with the spool. The prior art shows the use of two tubes, one insertable within the other, the outer tube having a longitudinal slot and the inner tube having an external rib extending through the slot for engaging the fabric along one edge of the slot to hold one end of the fabric, as shown in U.S. Pat. No. 1,183,819, issued May 16, 1916, on the application of Jan Keiser. U.S. Pat. No. 1,759,095, issued May 20, 1930, on the application of Charles W. Coker, shows an inner tube and a resilient, split outer tube wherein the fabric is inserted and held by the wrapping force as a spindle is turned. U.S. Pat. No. 2,390,894, issued Dec. 11, 1945, on the application of John F. Morse, shows a film spool having a central core member with an opening through which the film is inserted, the core member being eccentric on its inner surface, and a rotatable clamp having an enlargement engageable with the core member eccentric surface to lock the film in place. The core member rotates on the central axis of the spool in the clamping and unclamping action. Additionally, U.S. Pat. No. 3,333,309, issued Aug. 1, 1967, on the application of Nikolai H. K. Wistinghausen, shows a core clamp of resilient material, apertured to enable springing action, and having irregularly defined inner faces for locking a roll on a square shaft.
Although the above-noted U.S. patents teach the use of the various attaching, clamping, or fastening structures for the purposes intended, said structures are limited in application and operation. For instance, the success of U.S. Pat. No. 1,759,095 must depend upon the resiliency of the outer tube to press the fabric against the inner tube, and the result in U.S. Pat. No. 2,390,894 must depend upon a fixed axis clamp device contacting an eccentric surface on the interior of the core member. However, it is desirable that a clamping device be made available for securing a ribbon leader or the like on a spool wherein the clamping action is insured by the pull of the ribbon in rotating a movable-center core about the inside of the spool, and also wherein the device is adapted for ease of loading and unloading the ribbon and so constructed as not to interfere with the winding of the ribbon on the spool.
SUMMARY OF THE INVENTION
The present invention relates to ribbon-carrying spools and more particularly to means for locking and unlocking the end of the ribbon as the ribbon is wound on and unwound from the spool. The invention is particularly useful in the field of printers wherein a carbon ribbon is caused to be driven past a type line in continuous fashion, the ribbon traveling from one spool to another (for example, from a supply spool to a takeup spool). The ribbon supply spool is characterized by having a given quantity of ribbon wound thereon and placed on a printer in position so that, when the ribbon is unwound from the supply spool, it is carried in a path around a type drum and onto a takeup spool. The takeup spool includes a hollow metallic tube or mandrel, formed with a longitudinal opening or slot along a peripheral midsection thereof, and a core member inserted inside the mandrel, the core member being adapted to cooperate with the opening in the mandrel to receive the end of the ribbon and to secure it during winding of the ribbon onto the spool. The ribbon generally has a leader at one end thereof to be received into the opening and to be wound around the core in the space between the periphery of the core and the inside surface of the mandrel. The core member is of a diameter to be readily slidable inside the tube and also allow space for the ribbon leader to be wound for securing it. The core includes a pair of spacers or jutting elements fixed thereto near its ends, and positioned to ride along a predetermined angular distance in slots normal to the longitudinal opening formed in the mandrel. The longitudinal opening and the slot at either end thereof constitute a wide-based U-shaped construction for the ribbon leader to be received and for the spacers to travel when releasing the leader from the spool. The mandrel has a lip portion between the end slots, running adjacent and parallel to the longitudinal opening, and formed inwardly to decrease the diameter of the mandrel along a prescribed arc of the circle. The core is shaped to have a flattened surface cooperating with the mandrel portion, so that, upon rotation of the core to secure the leader, one edge of the surface is cammed against the lip portion, and, at the same time, the opposite edge of the flattened surface is cammed against an additional interior surface portion of the mandrel. The leader is thus secured around the core by the camming action in the two places by reason of the leader extending substantially around the core, and the ribbon is held in position as the mandrel is rotated.
As the mandrel is turned or rotated in one direction, the outward pull on the ribbon causes the core to rotate and the spacers to move along the end slots, the core entering into a wedged position along each of its edge surfaces, which clamps the ribbon leader along its length. As more force is applied on the leader, the more secure it becomes by reason of the wedging action. Rotation of the core in the opposite direction, by manual movement of the spacers along the slots, unlocks the edge surfaces of the core from the camming, or wedging, position and releases the ribbon leader for removal from the mandrel. With the leader inserted through the opening and guided around the core, the ribbon is securely clamped to the mandrel, and, the greater the pull exerted on the ribbon, the greater the clamping action between the core and the mandrel. Since the core includes a flattened surface on one side, it is free to rotate within the spool a certain distance and to seek the most effective clamping position by reason of its movable axis. In this respect, the center of the core is independent from the center of the spool.
In view of the above discussion, the principal object of the present invention is to provide locking means for securing the end of a ribbon on a spool, including a member adaptable for seeking its maximum clamping position.
An additional object of the present invention is to provide a spool having locking and unlocking features for ease in handling the end of the ribbon.
A further object of the present invention is to provide a ribbon spool with a clamping device which is self-contained within the spool for enabling winding of the ribbon thereon and unwinding the ribbon therefrom without the use of external tools.
Another object of the present invention is to provide locking and unlocking means in a ribbon spool which does not interfere with the winding and unwinding of the ribbon.
Additional advantages and features of the present invention will become apparent and fully understood from a reading of the following description taken together with the annexed drawing, in which:
FIG. 1 is a side view, in diagrammatic form, of a portion of a printer incorporating the present invention;
FIG. 2 is a perspective view of a takeup spool with the ribbon leader secured thereto; and
FIG. 3 is a view taken on the line 3--3 of FIG. 2.
Referring to FIG. 1, there is shown a portion of a printing mechanism including a type drum 12 rotatably carried by means of a shaft 14 connected to a suitable drive means (not shown). A carbon ribbon 16 is caused to be driven in a path past a type line during its travel from a supply spool 18 to a takeup spool 20. Record material 22, such as paper or the like, is likewise caused to be driven past a type hammer 24, so that, upon receipt of the signal to print, the hammer is driven against the paper, the carbon ribbon, and, in turn, a type element on the type drum 12, the result of which is an imprint of the selected type element on the paper. During printing operations, the paper and the ribbon are continuously driven past the type line, so that the ribbon 16 unwinds from the supply spool and winds around the takeup spool, it being necessary, of course, that the ribbon remain substantially taut at all times. In traveling along its path from one spool to the other, the ribbon is guided past an antiskew member 26, around rollers 28 and 30, and across a type drum protective cover 32.
Generally, the ribbon, as it comes from the manufacturer, includes a leader 36 (FIG. 2), which is provided on one end of the ribbon for the purpose of readily attaching the ribbon to the takeup spool, this spool being a tubular member made of plated steel. The leader is usually made of material sufficiently flexible to easily conform to the shape of the takeup spool, yet sufficiently rigid to provide securing and clamping capability. In this respect, the ribbon leader may be paper, cardboard, plastic, cloth, or the like which is readily securable to the ribbon by suitable means. The supply spool 18 is placed on mandrel chucks (not shown) spaced approximately the length of the spool, one of the chucks being spring loaded for ease of installation and to maintain pressure axially on the spool. Of course, the positions of the spools may be reversed from those shown in FIG. 1; that is, the upper spool may be used as the supply spool and the lower as the takeup spool, if the operation is more suitable in this manner.
The leader 36 is unwound from the supply spool 18 and threaded in a path around the type drum 12 and inserted into a longitudinal slot 38 (FIG. 2), which is longer than the width of the leader, and then around a plastic core member 40 (see also FIG. 1) previously placed within the spool 20. As seen in FIGS. 2 and 3, the spool 20 has, formed in its periphery, a portion adjacent the slot 38, which portion includes an inwardly directed formation 42 and an outwardly directed lip 44, the lip 44 stopping short of the exterior surface of the spool. The core member 40 is circular in shape and of lesser diameter than the inside diameter of the spool to rotate freely therein, and it has a flat surface 46 along one side thereof, defined by a chordal portion removed therefrom. A pair of spacers, detents, or abutments 48 and 49 are secured to the flat surface 46 by means of screws 50 and 51, there being a spacer provided adjacent each end of the core 40 and extending into extensions 52 and 54 of the slot 38, these extensions being so positioned as to form end slots for a predetermined distance around the circumference of the spool 20. As the core 40 is adaptable to be rotated within the spool 20, the spacers 48 and 49 are movable freely along the slot extensions 52 and 54, it being noted that the spacers with the securing screws are likewise within the extent of the outside diameter of the spool 20 to allow the ribbon to wrap around the spool without interference from the screws. The extent of the spacers and the screws adds sufficient diameter to the core member 40 so that the spacers are assembled to the core member after the core has been inserted into the spool from one end thereof. This extent of the spacers also insures that the core 40 will not inadvertently slide along the area of the slot 38 or out of range of the slot extensions 52 and 54, so as to permit uncontrolled movement in the clamping and releasing action thereof within the spool 20.
As mentioned above, the leader 36 is inserted through the slot 38 and threaded around the core member 48, the free end 60 of the leader passing an edge 61 of the surface 46 on its lower side (FIG. 3). In the securing, or clamping, position of the leader, a second edge 62 of the core surface 46 is against the leader and presses it into contact with the interior surface of the formation 42. In this respect, the leader 36 is firmly secured and clamped by the camming action at the core edge 61 pressing the leader against the interior surface of the spool 20 and at the core edge 62 pressing the ribbon against the spool formation 42. Looking at FIG. 3, when pull is exerted on the leader 36, the core member 40 is rotated clockwise, which cam the two edges 61 and 62 with the interior surface and the formation of the spool. The greater the pull on the leader, the greater the clamping action. This clamping action is accomplished by reason of the core member's being independent of the axis of the spool as the core seeks its own center in the clamping position. As the spool is rotated on the mandrel chucks, the leader and the ribbon are wound on the spool in circular manner, the lip portion 44 and the screws 50 and 51 being within the periphery of the spool and completely covered during winding and unwinding of the ribbon.
When the ribbon is unwound from the spool, the leader again takes the position shown in FIG. 3, so that it is still taut around the core member 40. The leader is very easily released from the clamping action of the core 40 by moving the spacers 48 and 49 counterclockwise along the slot extensions 52 and 54, which movement rotates the core away from the spool clamping surfaces to permit the leader to be pulled from around the core and out through the slot 38. Since the spacers are beyond the edges of the leader (FIG. 2), it is a simple matter to manually so turn the core thereby for releasing the ribbon from the spool.
It is thus seen that herein shown and described is a holding or clamping device for a ribbon leader which device accomplishes all the features and advantages mentioned above. While only one embodiment has been disclosed, certain variations on the above may occur to those skilled in the art, so it is contemplated that all such variations having these features are within the scope of the invention.