CA1059096A - Apparatus for holding cylindrical winding cores - Google Patents
Apparatus for holding cylindrical winding coresInfo
- Publication number
- CA1059096A CA1059096A CA256,731A CA256731A CA1059096A CA 1059096 A CA1059096 A CA 1059096A CA 256731 A CA256731 A CA 256731A CA 1059096 A CA1059096 A CA 1059096A
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- Canada
- Prior art keywords
- pressure chamber
- hollow shaft
- annular body
- pressure
- core holder
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
Winding apparatus for cylindrical winding cores com-prises a plurality of core holders and a plurality of friction collars arranged under axial pressure alternately on a single hollow shaft, each of the friction collars being axially mov-able and constrained in rotation and each of said core holders having a radially expansible member which can be radially ex-panded by air pressure supplied through the hollow shaft to come into pressure engagement with the inner surface of a cy-lindrical winding core disposed about the core holder.
Winding apparatus for cylindrical winding cores com-prises a plurality of core holders and a plurality of friction collars arranged under axial pressure alternately on a single hollow shaft, each of the friction collars being axially mov-able and constrained in rotation and each of said core holders having a radially expansible member which can be radially ex-panded by air pressure supplied through the hollow shaft to come into pressure engagement with the inner surface of a cy-lindrical winding core disposed about the core holder.
Description
lOS9096 This invention relates to winding apparatus, which term includes rewinding apparatus, and more particularly to such ap-paratus in which a plurality of paper tube cores can be support-ed on a single winding shaft in such a manner that said paper tube cores may be independently friction-slipped.
A paper tube supporting device of the individual fric-tion type in which friction collars and paper tube holders are alternately arranged on a single center shaft and held in posi-tion with an axial pressure applied thereto is known. In such a device, a number of paper tube cores each having a length ex-tending over one or a plurality of holders are mounted on a single shaft and are simultaneously rotated by the rotation of the shaft to simultaneously take up or rewind slit paper strips or other long-sized sheet materials. In this connection, since each holder is capable of frictionally slipping relative to ad-jacent friction collars, each paper tube core is capable of slipping independently of the shaft in a reasonable manner. In the conventional device of this type, the holder is provided on the outer surface thereof with tangentially projecting serra-tions for engagement with a paper tube core so as to penetratethe inner surface of the latter. However, the use of such holders involves much time and labor in mounting and dismount-ing paper tubes and has the disadvantage of damaging paper tube cores and, moreover, the serrations are dangerousto the operator.
An object of the invention is to provide a new and im-proved winding apparatus for cylindrical winding cores, in which the mounting and dismounting of paper tube cores are carried out simultaneously and automatically through the utilization of pneumatic pressure.
According to the present invention there is provided winding apparatus for cylindrical winding cores, comprising a rotatable hollow shaft having a plurality of apertures ar- -ranged at intervals along its length to communicate the inside thereof with the outside thereof; means for supplying a pneuma-tic pressure to the inside of the hollow shaft; an arrangement of a plurality of friction collars and a plurality of core hold-er assemblies alternately arranged on a hollow shaft; and means for holding the arrangement of the plurality of friction collars and the plurality of core holder assemblies on the hol-low shaft under pressure in the direction of the axis of the hollow shaft; each of the friction collars being axially slid-able along the hollow shaft but so constrained as to rotate to-gether with the hollow shaft, and each of the core holder assem-blies comprising an annular body frictionally supported between a respective pair of the friction collars, the annular body de-fining a pressure chamber therein and having at least one open-ing between the pressure chamber and the outside of the annular body and at least one other opening communicating the pressure chamber with the inside of the hollow shaft through the aper-ture for introduction of the pneumatic pressure to the pressure chamber, expansible means disposed in the pressure chamber, the expansible means being radially expansible in response to the pneumatic pressure introduced to the pressure chamber, and catch means attached to the expansible means, the catch means being movable, with movement of the expansible means, through the open-ing in the outer peripheral wall of the annular body between a first position at which a free end of the catch means projects from the opening in the outer peripheral wall and is engageable with the inside wall surface of a cylindrical core when placed about the annular body and a second position at which the catch means is retracted from the first position.
In a preferred embodiment of the invention, in each of said core holder assemblies the pressure chamber is defined by an outer peripheral wall, an inner peripheral wall, and a pair of end walls, the at least one opening between the pressure chamber and the outside of the annular body being in the outer peripheral wall and the at least one opening communicating the pressure chamber with the inside of the hollow shaft through the aperture being in the inner peripheral wall. In this case the expansible means preferably comprises an elastic annular member substantially covering the inside wall surface of each of the outer peripheral wall and the end walls of the annular body.
Preferably each of said core holder assemblies further includes spring means for returning the catch means from the first position to the second position when the pneumatic pres-sure is not supplied to the pressure chamber.
Desirably each respective pair of said friction collars frictionally engage with the core holder assembly therebetween at the end walls and the inner wall of the annular body.
The invention will be further understood from the follow-ing description by way of example with reference to the accompany-ing drawings, in which:-Figure 1 is a partly cut-away view of a winding shaft incorporating an embodiment of the invention;
Figure 2 is an enlarged partly sectional view of part of the winding shaft illustrated in Figure l; and Figures 3 and 4, which appear on the same sheet as Figure 1, are vertical sectional views of the winding shaft taken along lines 3-3 and 4-4, respectively, in Figure 2.
~, Referring to the drawings, particularly to Figure 1, a plurality of friction collars 11 and a plurality of core holder assemblies 12 are alternately aranged on a driven hollow shaft 13 between a pair of end collars 14 and 15. The shaft 13 is rotatably supported at its opposite end portions by suitable bearing means (not shown). A drive force for ro-tation may be transmitted to the shaft 13 at one end 13a, which also provides for connection to a pneumatic pressure source (not shown) for supplying a pneumatic pressure to the inside of the hollow shaft 13. The end collar 14 abuts against a flange 17 integrally formed on the shaft 13. The other end collar 15 is slidable along the shaft 13 and is spaced from an end cover 18 which is fixed to the hollow shaft 13 to close the other end thereof. Disposed between the end collar 15 and the end cover 18 is a spring 19 which urges the whole arrangement of friction collars 11, core holder assemblies 12, and end collars 14 and 15 towards the flange 17.
The arrangement of the friction collars 11 and the core holder assemblies 12 on the dri ~ hollow shaft 13 is illustrat-ed in more detail in Figures 2 to 4. The shaft 13 has a plura-lity of apertures 21 arranged at regular intervals along its length to communicate the inside thereof with the outside thereof.
Each of the friction collars 11 is shaped in the form of a sleeve having a flange lla at the middle of its length, and is mounted on the shaft 13 in such a manner that it is axially slidable along the shaft 13 but is so constrained as to rotate together with the shaft 13. The reference numeral 22 (Figure
A paper tube supporting device of the individual fric-tion type in which friction collars and paper tube holders are alternately arranged on a single center shaft and held in posi-tion with an axial pressure applied thereto is known. In such a device, a number of paper tube cores each having a length ex-tending over one or a plurality of holders are mounted on a single shaft and are simultaneously rotated by the rotation of the shaft to simultaneously take up or rewind slit paper strips or other long-sized sheet materials. In this connection, since each holder is capable of frictionally slipping relative to ad-jacent friction collars, each paper tube core is capable of slipping independently of the shaft in a reasonable manner. In the conventional device of this type, the holder is provided on the outer surface thereof with tangentially projecting serra-tions for engagement with a paper tube core so as to penetratethe inner surface of the latter. However, the use of such holders involves much time and labor in mounting and dismount-ing paper tubes and has the disadvantage of damaging paper tube cores and, moreover, the serrations are dangerousto the operator.
An object of the invention is to provide a new and im-proved winding apparatus for cylindrical winding cores, in which the mounting and dismounting of paper tube cores are carried out simultaneously and automatically through the utilization of pneumatic pressure.
According to the present invention there is provided winding apparatus for cylindrical winding cores, comprising a rotatable hollow shaft having a plurality of apertures ar- -ranged at intervals along its length to communicate the inside thereof with the outside thereof; means for supplying a pneuma-tic pressure to the inside of the hollow shaft; an arrangement of a plurality of friction collars and a plurality of core hold-er assemblies alternately arranged on a hollow shaft; and means for holding the arrangement of the plurality of friction collars and the plurality of core holder assemblies on the hol-low shaft under pressure in the direction of the axis of the hollow shaft; each of the friction collars being axially slid-able along the hollow shaft but so constrained as to rotate to-gether with the hollow shaft, and each of the core holder assem-blies comprising an annular body frictionally supported between a respective pair of the friction collars, the annular body de-fining a pressure chamber therein and having at least one open-ing between the pressure chamber and the outside of the annular body and at least one other opening communicating the pressure chamber with the inside of the hollow shaft through the aper-ture for introduction of the pneumatic pressure to the pressure chamber, expansible means disposed in the pressure chamber, the expansible means being radially expansible in response to the pneumatic pressure introduced to the pressure chamber, and catch means attached to the expansible means, the catch means being movable, with movement of the expansible means, through the open-ing in the outer peripheral wall of the annular body between a first position at which a free end of the catch means projects from the opening in the outer peripheral wall and is engageable with the inside wall surface of a cylindrical core when placed about the annular body and a second position at which the catch means is retracted from the first position.
In a preferred embodiment of the invention, in each of said core holder assemblies the pressure chamber is defined by an outer peripheral wall, an inner peripheral wall, and a pair of end walls, the at least one opening between the pressure chamber and the outside of the annular body being in the outer peripheral wall and the at least one opening communicating the pressure chamber with the inside of the hollow shaft through the aperture being in the inner peripheral wall. In this case the expansible means preferably comprises an elastic annular member substantially covering the inside wall surface of each of the outer peripheral wall and the end walls of the annular body.
Preferably each of said core holder assemblies further includes spring means for returning the catch means from the first position to the second position when the pneumatic pres-sure is not supplied to the pressure chamber.
Desirably each respective pair of said friction collars frictionally engage with the core holder assembly therebetween at the end walls and the inner wall of the annular body.
The invention will be further understood from the follow-ing description by way of example with reference to the accompany-ing drawings, in which:-Figure 1 is a partly cut-away view of a winding shaft incorporating an embodiment of the invention;
Figure 2 is an enlarged partly sectional view of part of the winding shaft illustrated in Figure l; and Figures 3 and 4, which appear on the same sheet as Figure 1, are vertical sectional views of the winding shaft taken along lines 3-3 and 4-4, respectively, in Figure 2.
~, Referring to the drawings, particularly to Figure 1, a plurality of friction collars 11 and a plurality of core holder assemblies 12 are alternately aranged on a driven hollow shaft 13 between a pair of end collars 14 and 15. The shaft 13 is rotatably supported at its opposite end portions by suitable bearing means (not shown). A drive force for ro-tation may be transmitted to the shaft 13 at one end 13a, which also provides for connection to a pneumatic pressure source (not shown) for supplying a pneumatic pressure to the inside of the hollow shaft 13. The end collar 14 abuts against a flange 17 integrally formed on the shaft 13. The other end collar 15 is slidable along the shaft 13 and is spaced from an end cover 18 which is fixed to the hollow shaft 13 to close the other end thereof. Disposed between the end collar 15 and the end cover 18 is a spring 19 which urges the whole arrangement of friction collars 11, core holder assemblies 12, and end collars 14 and 15 towards the flange 17.
The arrangement of the friction collars 11 and the core holder assemblies 12 on the dri ~ hollow shaft 13 is illustrat-ed in more detail in Figures 2 to 4. The shaft 13 has a plura-lity of apertures 21 arranged at regular intervals along its length to communicate the inside thereof with the outside thereof.
Each of the friction collars 11 is shaped in the form of a sleeve having a flange lla at the middle of its length, and is mounted on the shaft 13 in such a manner that it is axially slidable along the shaft 13 but is so constrained as to rotate together with the shaft 13. The reference numeral 22 (Figure
2) indicates a key inserted between each of the friction col-lars 11 and the shaft 13.
Each of the core holder assemblies 12 is disposed bet-ween a respective pair of the friction collars 11. Friction collars 11 are disposed between the end collars 14 and 15 and the end core holder assemblies.
Each of the core assemblies 12 comprises an annular body which is in contact with and frictionally supported by and be-tween the respective pair of the friction collars 11. The annu-lar body comprises an outer ring 31a and an inner ring 31b which are connected to each other by suitable fastening means such as screws 32. The outer ring and the inner ring cooperate to form a pressure chamber 33 therebetween, the outer ring 31a forming an outer peripheral wall of the pressure chamber 33 and the inner ring 31b forming an inner peripheral wall and a pair of end walls of the pressure chamber 33. The inner ring 31b frictionally engages the friction collars 11 both at the outside surfaces of its end walls and at the outer exposed sur-face of its inner peripheral wall. The outer ring 31a is pro-vided with at least one window opening, preferably a plurality of (e.g. four) window openings 34, communicating the pressure chamber 33 with the outside of the annular body 31. The inner ring 31b which forms the inner peripheral wall of the annular body is provided with at least one opening 35 communicating the pressure chamber 33 with the inside of the hollow shaft 13 through a respective aperture 21 for introduction of pneumatic pressure to the pressure chamber 33.
Disposed in each pressure chamber 33 is a member 36 which is radially expansible in response to the pneumatic pres-sure introduced to the pressure chamber 33, and comprises an elastic annular half tube substantially covering the inside wall surface of each of the outer peripheral wall and the end walls of the annular body.
~,~
Attached to each expansible member 36 are friction catch buttons 37 which are movable together with the expansible member 36 through the respective openings 34 in the outer peri-pheral wall of the outer ring 31a of the annular body between a first position, shown in`Figure 4 and in the right-hand part of Figure 2, in which the free end of each of the catch buttons 37 projects from the opening 34 in the outer peripheral wall and becomes engageable with the inside wall surface of a paper tube core 41 when placed about said annular body, and a re-tracted position, shown in Figure 3 and in the left-hand part of Figure 2, in which each of said catch buttons 37 is separat-ed from the inside wall surface of the paper tube core 41. Each of the catch buttons 37 is attached to the expansible half tube 36 via a respective leaf spring 39. Each leaf spring 39 func-tions as a return spring for returning the catch button 37 from its projected position to its retracted position when pneumatic pressure falls in the pressure chamber 33; when pneumatic pres-sure is supplied to the pressure chamber 33, the leaf spring 39 cooperates with expansion of the elastic half tube 36 to push the respective catch button 37 outwardly of the respective opening 34.
Seal rings 51 are provided around the hollow shaft 13 so as to bridge between respective pairs of the friction col-lars 11. The outer peripheral surface of each seal ring 51 is in slidable contact with the inner wall of eac-h of the respective fric-tion collars 11. The reference numeral 52 indicates grease re-servoir recesses to prevent air leakage through the contact sur-face between the seal rings 51 and the friction collars 11.
Each seal ring 51 is also provided with a small through hole 53 for communicating the opening 35 of the inner wall of the annu-~6~
10590!~6 lar body with the aperture 21 of the hollow shaft 13.
Paper tube cores 41 can be fitted over the core assem-blies 12. The inner diameter of the paper cores 41 is slightly larger than the outer diameter of the outer ring 31a of each of the core holder assemblies so that the paper tube cores 41 can be freely fitted over the core holder assemblies 12. In such condition, when an air pressure is supplied into the interior of the hollow shaft 13 through the end thereof, such air pres-sure is introduced into the individual pressure chambers 33 through the apertures 21, the holes 53 and the openings 35, causing the expansible half tubes 36 to be radially expanded, with the buttons 37 projecting through the window openings 34 until they are pressed against the inner surfacesof the paper tube cores 41 (see Figure 4and the right half of Figure 2), there-by enabling the paper tube cores to be held by the core holder assemblies 12. When the supply of air pressure is stopped, the expansible half tubes 36 are contracted to their original, retracted, position to release the paper tube cores 41. The left two core holder assemblies illustrated in Figure 2 show the state in which the buttons 37 are in the retracted positions.
During the operation of the winding shaft, either said air pres-sure is continuously supplied, or both ends of the shaft 13 are sealed so as to maintain the air pressure in the interior.
Slit paper strips or other materials may be wrapped around the papcr tube cores 41 thus held by the core holder assemblies, and the shaft is positively driven at a speed fas-ter than that of the paper tube cores and core holder assemblies, whereby the core holder assemblies 12, while slipping by an amount corresponding to the difference in the rotative speeds, are passively driven by said friction torque due to their slippage.
.,, . ~
As for the friction torque, any desired value may be obtained by changing the magnitude of the axial pressure applied by the spring 19 from the shaft end, and hence wound articles of any desired winding hardness can be obtained.
Because the mounting of the paper tube cores 41 is ach-ievèd by pneumatic means making use of the expansible members 36, the mounting and dismounting and fixing and releasing of paper tube cores 41 with respect to the winding shaft can all be extremely simply effected. As there is no need to provide serrations on paper tube holders as in the conventional device, there is no possibility of damaging the paper tube cores, nor is there any danger involved in mounting and dismounting the paper tubes.
Further, the components are simple in construction and require little manual operation, and they are also economically advantageous because they are highly durable.
In addition, in actual examples of use as when winding thin films, the winding tension required is very low in the case of films of several hundred mm in width, a large number of holders applied to the paper tube cores is required and the required lateral pressure applied from one end may frequently be relatively low. In this connection, the shafts of the con-ventional individual friction type have the disadvantages that such very small pressure fails to be uniformly transmitted through all the holders on the shaft and that the unevenness of the roughness of the friction surfaces makes it impossible to achieve a uniform friction torque. In the case of the present winding shaft, however, the action of spontaneously equalizing the friction unevenness of the friction surfaces is produced, thereby substantially eliminating the above described disadvantages.
~8~
More specifically, in the present winding shaft the pre-ssure on the friction surface for producing said friction tor-que is the lateral pressure applied from the shaft and minus the pressure provided by the air pressure acting on the lateral end area of the friction collar 11, so that there is the advan-tage of being able to correspondingly increase the lateral pre-ssureO In other words, the friction surfaces are constantly subjected to an action from the air pressure tending to enlarge the clearances.
Thus, with an air pressure being introduced into the pressure chamber 33, if the very small clearance between the inner ring 31b to the annular body in any one of the pressure chambers 33 and an adjacent friction collar 11 becomes any wider than the clearance related to an adjacent pressure chamber, then the amount of air leaking through said wider clearance becomes larger than that leaking through said second clearance and hence the air pressure in the pressure chamber under con-sideration becomes lower than that in said second pressure chamber 33, whereby the friction collar 11 subjected to the pressures in the pressure chambers 33 is moved a very small amount axially toward the pressure-decreased pressure chamber 33 to narrow the clearance and reduce the leakage of air, so as to balance the air pressures in the pressure chambers 33.
In this manner, the action of equalizing the pressures on the friction surfaces and hence the friction torques is achieved.
This effect increases if the holes 53 are made finer.
Such changes in the clearance between the friction surfaces are very small, of the order of microns, and they can be caused not only by the movement of the collars and holders but also by even a very small amount of deformation of the com-~, 1059~)96 ponents due to changes in pressure, however high the rigidity ofthe components may be.
While the above action has been described with reference to two adjacent pressure chambers, the same action will take place between spaced regions (each including a plurality of bobbins) along a long shaft on which a number of collars and bobbins are installed. In that case, along with the friction collars 11, the core holder assemblies 12 are also axially mov-ed a very small amount, and when a plurality of sets of these collars and holders are moved, the net amount of movement is the sum of the individual amounts of movement.
As described above, in the present winding shaft the interaction between the externally applied lateral pressure and the force returned from the interior by the air pressure con-stantly moves the collars and bobbins from side to side by very small amounts, resulting in providing the suxprisingly sup-erior function of equalizing friction torques throughout the length of the shaft.
Each of the core holder assemblies 12 is disposed bet-ween a respective pair of the friction collars 11. Friction collars 11 are disposed between the end collars 14 and 15 and the end core holder assemblies.
Each of the core assemblies 12 comprises an annular body which is in contact with and frictionally supported by and be-tween the respective pair of the friction collars 11. The annu-lar body comprises an outer ring 31a and an inner ring 31b which are connected to each other by suitable fastening means such as screws 32. The outer ring and the inner ring cooperate to form a pressure chamber 33 therebetween, the outer ring 31a forming an outer peripheral wall of the pressure chamber 33 and the inner ring 31b forming an inner peripheral wall and a pair of end walls of the pressure chamber 33. The inner ring 31b frictionally engages the friction collars 11 both at the outside surfaces of its end walls and at the outer exposed sur-face of its inner peripheral wall. The outer ring 31a is pro-vided with at least one window opening, preferably a plurality of (e.g. four) window openings 34, communicating the pressure chamber 33 with the outside of the annular body 31. The inner ring 31b which forms the inner peripheral wall of the annular body is provided with at least one opening 35 communicating the pressure chamber 33 with the inside of the hollow shaft 13 through a respective aperture 21 for introduction of pneumatic pressure to the pressure chamber 33.
Disposed in each pressure chamber 33 is a member 36 which is radially expansible in response to the pneumatic pres-sure introduced to the pressure chamber 33, and comprises an elastic annular half tube substantially covering the inside wall surface of each of the outer peripheral wall and the end walls of the annular body.
~,~
Attached to each expansible member 36 are friction catch buttons 37 which are movable together with the expansible member 36 through the respective openings 34 in the outer peri-pheral wall of the outer ring 31a of the annular body between a first position, shown in`Figure 4 and in the right-hand part of Figure 2, in which the free end of each of the catch buttons 37 projects from the opening 34 in the outer peripheral wall and becomes engageable with the inside wall surface of a paper tube core 41 when placed about said annular body, and a re-tracted position, shown in Figure 3 and in the left-hand part of Figure 2, in which each of said catch buttons 37 is separat-ed from the inside wall surface of the paper tube core 41. Each of the catch buttons 37 is attached to the expansible half tube 36 via a respective leaf spring 39. Each leaf spring 39 func-tions as a return spring for returning the catch button 37 from its projected position to its retracted position when pneumatic pressure falls in the pressure chamber 33; when pneumatic pres-sure is supplied to the pressure chamber 33, the leaf spring 39 cooperates with expansion of the elastic half tube 36 to push the respective catch button 37 outwardly of the respective opening 34.
Seal rings 51 are provided around the hollow shaft 13 so as to bridge between respective pairs of the friction col-lars 11. The outer peripheral surface of each seal ring 51 is in slidable contact with the inner wall of eac-h of the respective fric-tion collars 11. The reference numeral 52 indicates grease re-servoir recesses to prevent air leakage through the contact sur-face between the seal rings 51 and the friction collars 11.
Each seal ring 51 is also provided with a small through hole 53 for communicating the opening 35 of the inner wall of the annu-~6~
10590!~6 lar body with the aperture 21 of the hollow shaft 13.
Paper tube cores 41 can be fitted over the core assem-blies 12. The inner diameter of the paper cores 41 is slightly larger than the outer diameter of the outer ring 31a of each of the core holder assemblies so that the paper tube cores 41 can be freely fitted over the core holder assemblies 12. In such condition, when an air pressure is supplied into the interior of the hollow shaft 13 through the end thereof, such air pres-sure is introduced into the individual pressure chambers 33 through the apertures 21, the holes 53 and the openings 35, causing the expansible half tubes 36 to be radially expanded, with the buttons 37 projecting through the window openings 34 until they are pressed against the inner surfacesof the paper tube cores 41 (see Figure 4and the right half of Figure 2), there-by enabling the paper tube cores to be held by the core holder assemblies 12. When the supply of air pressure is stopped, the expansible half tubes 36 are contracted to their original, retracted, position to release the paper tube cores 41. The left two core holder assemblies illustrated in Figure 2 show the state in which the buttons 37 are in the retracted positions.
During the operation of the winding shaft, either said air pres-sure is continuously supplied, or both ends of the shaft 13 are sealed so as to maintain the air pressure in the interior.
Slit paper strips or other materials may be wrapped around the papcr tube cores 41 thus held by the core holder assemblies, and the shaft is positively driven at a speed fas-ter than that of the paper tube cores and core holder assemblies, whereby the core holder assemblies 12, while slipping by an amount corresponding to the difference in the rotative speeds, are passively driven by said friction torque due to their slippage.
.,, . ~
As for the friction torque, any desired value may be obtained by changing the magnitude of the axial pressure applied by the spring 19 from the shaft end, and hence wound articles of any desired winding hardness can be obtained.
Because the mounting of the paper tube cores 41 is ach-ievèd by pneumatic means making use of the expansible members 36, the mounting and dismounting and fixing and releasing of paper tube cores 41 with respect to the winding shaft can all be extremely simply effected. As there is no need to provide serrations on paper tube holders as in the conventional device, there is no possibility of damaging the paper tube cores, nor is there any danger involved in mounting and dismounting the paper tubes.
Further, the components are simple in construction and require little manual operation, and they are also economically advantageous because they are highly durable.
In addition, in actual examples of use as when winding thin films, the winding tension required is very low in the case of films of several hundred mm in width, a large number of holders applied to the paper tube cores is required and the required lateral pressure applied from one end may frequently be relatively low. In this connection, the shafts of the con-ventional individual friction type have the disadvantages that such very small pressure fails to be uniformly transmitted through all the holders on the shaft and that the unevenness of the roughness of the friction surfaces makes it impossible to achieve a uniform friction torque. In the case of the present winding shaft, however, the action of spontaneously equalizing the friction unevenness of the friction surfaces is produced, thereby substantially eliminating the above described disadvantages.
~8~
More specifically, in the present winding shaft the pre-ssure on the friction surface for producing said friction tor-que is the lateral pressure applied from the shaft and minus the pressure provided by the air pressure acting on the lateral end area of the friction collar 11, so that there is the advan-tage of being able to correspondingly increase the lateral pre-ssureO In other words, the friction surfaces are constantly subjected to an action from the air pressure tending to enlarge the clearances.
Thus, with an air pressure being introduced into the pressure chamber 33, if the very small clearance between the inner ring 31b to the annular body in any one of the pressure chambers 33 and an adjacent friction collar 11 becomes any wider than the clearance related to an adjacent pressure chamber, then the amount of air leaking through said wider clearance becomes larger than that leaking through said second clearance and hence the air pressure in the pressure chamber under con-sideration becomes lower than that in said second pressure chamber 33, whereby the friction collar 11 subjected to the pressures in the pressure chambers 33 is moved a very small amount axially toward the pressure-decreased pressure chamber 33 to narrow the clearance and reduce the leakage of air, so as to balance the air pressures in the pressure chambers 33.
In this manner, the action of equalizing the pressures on the friction surfaces and hence the friction torques is achieved.
This effect increases if the holes 53 are made finer.
Such changes in the clearance between the friction surfaces are very small, of the order of microns, and they can be caused not only by the movement of the collars and holders but also by even a very small amount of deformation of the com-~, 1059~)96 ponents due to changes in pressure, however high the rigidity ofthe components may be.
While the above action has been described with reference to two adjacent pressure chambers, the same action will take place between spaced regions (each including a plurality of bobbins) along a long shaft on which a number of collars and bobbins are installed. In that case, along with the friction collars 11, the core holder assemblies 12 are also axially mov-ed a very small amount, and when a plurality of sets of these collars and holders are moved, the net amount of movement is the sum of the individual amounts of movement.
As described above, in the present winding shaft the interaction between the externally applied lateral pressure and the force returned from the interior by the air pressure con-stantly moves the collars and bobbins from side to side by very small amounts, resulting in providing the suxprisingly sup-erior function of equalizing friction torques throughout the length of the shaft.
Claims (5)
1. Winding apparatus for cylindrical winding cores, comprising:
a rotatable hollow shaft having a plurality of apertures arranged at intervals along its length to communicate the inside thereof with the outside thereof;
means for supplying a pneumatic pressure to the inside of said hollow shaft;
an arrangement of a plurality of friction collars and a plurality of core holder assemblies alternately arranged on said hollow shaft; and means for holding said arrangement of said plurality of friction collars and said plurality of core holder assemblies on said hollow shaft under pressure in the direction of the axis of said hollow shaft;
each of said friction collars being axially slidable along said hollow shaft but so constrained as to rotate together with said hollow shaft, and each of said core holder assemblies comprising:
an annular body frictionally supported between a respec-tive pair of said friction collars, said annular body defining a pressure chamber therein and having at least one opening between said pressure chamber and the outside of said annular body and at least on other opening communicating said pressure chamber with the inside of said hollow shaft through said aperture for introduction of said pneumatic pressure to said pressure chamber, expansible means disposed in said pressure chamber, said expansible means being radially expansible in response to said pneumatic pressure introduced to said pressure chamber, and catch means attached to said expansible means, said catch means being movable, with movement of said expansible means, through said opening in said outer peripheral wall of said annular body between a first position at which a free end of said catch means projects from said opening in said outer peripheral wall and is engageable with the inside wall surface of a cylindrical core when placed about said annular body and a second position at which said catch means is retracted from said first position.
a rotatable hollow shaft having a plurality of apertures arranged at intervals along its length to communicate the inside thereof with the outside thereof;
means for supplying a pneumatic pressure to the inside of said hollow shaft;
an arrangement of a plurality of friction collars and a plurality of core holder assemblies alternately arranged on said hollow shaft; and means for holding said arrangement of said plurality of friction collars and said plurality of core holder assemblies on said hollow shaft under pressure in the direction of the axis of said hollow shaft;
each of said friction collars being axially slidable along said hollow shaft but so constrained as to rotate together with said hollow shaft, and each of said core holder assemblies comprising:
an annular body frictionally supported between a respec-tive pair of said friction collars, said annular body defining a pressure chamber therein and having at least one opening between said pressure chamber and the outside of said annular body and at least on other opening communicating said pressure chamber with the inside of said hollow shaft through said aperture for introduction of said pneumatic pressure to said pressure chamber, expansible means disposed in said pressure chamber, said expansible means being radially expansible in response to said pneumatic pressure introduced to said pressure chamber, and catch means attached to said expansible means, said catch means being movable, with movement of said expansible means, through said opening in said outer peripheral wall of said annular body between a first position at which a free end of said catch means projects from said opening in said outer peripheral wall and is engageable with the inside wall surface of a cylindrical core when placed about said annular body and a second position at which said catch means is retracted from said first position.
2. Apparatus as claimed in Claim 1 in which in each of said core holder assemblies said pressure chamber is defined by an outer peripheral wall, an inner peripheral wall, and a pair of end walls, said at least one opening between said pressure chamber and the outside of said annular body being in said outer pheripheral wall and said at least one opening communicating said pressure chamber with the inside of said hollow shaft through said aperture being in said inner peripheral wall.
3. Apparatus as claimed in Claim 2 in which said expan-sible means comprises an elastic annular member substantially covering the inside wall surface of each of said outer peripheral wall and said end walls of said annular body.
4. Apparatus as claimed in Claim 1, 2 or 3 wherein each of said core holder assemblies further includes spring means for returning said catch means from said first position to said second position when said pneumatic pressure is not supplied to said pressure chamber.
\
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5. Apparatus as claimed in Claim 2 or 3 in which each respective pair of said friction collars frictionally engage with the core holder assembly therebetween at said end walls and said inner wall of said annular body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA256,731A CA1059096A (en) | 1976-07-09 | 1976-07-09 | Apparatus for holding cylindrical winding cores |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA256,731A CA1059096A (en) | 1976-07-09 | 1976-07-09 | Apparatus for holding cylindrical winding cores |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1059096A true CA1059096A (en) | 1979-07-24 |
Family
ID=4106408
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA256,731A Expired CA1059096A (en) | 1976-07-09 | 1976-07-09 | Apparatus for holding cylindrical winding cores |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1059096A (en) |
-
1976
- 1976-07-09 CA CA256,731A patent/CA1059096A/en not_active Expired
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