Title:
ROLLING DOOR OPERATING MECHANISM
Document Type and Number:
United States Patent 3637004
Abstract:
A clutch for a rolling door operating mechanism safeguards a door counterbalance mechanism by actuating a rotatable brake member against a stationary drum should the counterbalance fail. The brake is released again by normally driving the operating mechanism. In one form, the clutch is arranged on a stationary shaft coaxially with the driving input; in a second form the clutch is on the rotatable shaft of the door barrel.
Inventors:
Wardlaw, Russell (San Rafael, CA)
Cole, Robert Peter (San Francisco, CA)
Cole, Robert Peter (San Francisco, CA)
Plaque It!
Sponsored by: Flash of Genius |
Application Number:
04/869212
Publication Date:
01/25/1972
Filing Date:
10/24/1969
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Export Citation:
Assignee:
The Cookson Company (San Francisco, CA)
Primary Class:
Other Classes:
160/189
International Classes:
E06B9/68; E06B9/84; E06B9/80; E06B9/208; E06B9/08
Field of Search:
160/133,189,191,8,9 49/322 74/625
US Patent References:
Primary Examiner:
Bell, Karl J.
Claims:
We claim
1. In a rolling door operating mechanism including a rollable curtain mountable for movement between raised and lowered positions and counterbalance means providing a bias against movement of the curtain to its lowered position, the combination comprising a driven member rotatable in one direction for moving the curtain towards its raised position and rotatable in the opposite direction for moving the curtain towards its lowered position, a reversible driving member for driving said driven member in both of said directions and including drive connection means for transferring driving forces from said driving to said driven member, safety means for stopping the rotational movement of said driven member in said opposite direction serving to halt the uncontrolled movement by gravity of the curtain to the lowered position upon failure of the counterbalance means, said safety means including relatively movable, confronting first and second friction members, said second friction member being drivable in both directions by said drive connection means, cam means including a cam follower arranged on said driven member and cooperative with said second friction member, said cam means being operative in response to uncontrolled rotation of said driven member by gravity movement of the curtain to urge said second friction member into frictional engagement with said first friction member serving to halt the rotation of said driven member in said opposite direction, said cam means being maintained in the inoperative condition in response to movement of said driven member by said driving member.
2. The subject matter of claim 1 wherein said friction members are concentrically arranged with said driven member, said second friction member being radially expandable, and said cam means serving to expand said second friction member into frictional engagement with said first friction member.
3. The subject matter of claim 2 wherein said second friction member is provided with a gap in its periphery, ramp portions on either side of said gap, said cam follower being disposed in engagement with said ramp portions.
4. The subject matter of claim 2 wherein said second friction member includes two, arcuately spaced, internally projecting dogs alternately engageable by said drive connection means for rotating said second friction member in synchronism with said driving member.
5. In a rolling door operating mechanism including a rollable curtain mountable for movement between raised and lowered positions and counterbalance means providing a bias against movement of the curtain to its lowered position, the combination comprising a rotatable member having a mechanical connection with the rollable curtain for rotation in opposite directions respectively in response to movement of the curtain to different ones of said positions, a stationary brake drum arranged concentrically of said rotatable member, radially expandable, brake band means mounted within said brake drum for movement into and out of the frictional engagement with said brake drum, said brake band and drum when in frictional engagement being effective to prevent the rotational movement of said member in said opposite direction serving to halt the uncontrolled movement by gravity of the curtain to the lowered position upon failure of the counterbalance means, a driving member mounted for angular movement between two operating positions relative to said rotatable member for driving the same, means interconnecting said brake band, rotatable, and drive members and rendering said driving member operative to rotate said brake band and rotatable member in opposite rotational directions respectively upon movement of said drive member to its said operating positions, cam means arranged on said rotatable member, brake band expanding means cooperable with said cam means to expand said brake bank into frictional engagement with said brake drum in response to rotation of said rotatable member by said curtain through said mechanical connection.
6. The subject matter of claim 5 wherein said brake band expanding means includes ramp portions arranged on said brake band on either side of the gap in its periphery, a cam follower carried on said cam means and projecting radially outwardly for cooperative engagement with said ramp portions.
7. The subject matter of claim 6 wherein said interconnecting means comprises arcuately spaced apart driving surfaces arranged on one of said members and diametrically oppositely extending shoulders arranged on the other two of said members for alternate engagement with said driving surfaces.
8. The subject matter of claim 5 wherein said interconnecting means includes a crescent shaped body on said drive member and means on said brake band and rotatable member defining drive shoulders cooperable with said body for rotating said brake band and rotatable member.
1. In a rolling door operating mechanism including a rollable curtain mountable for movement between raised and lowered positions and counterbalance means providing a bias against movement of the curtain to its lowered position, the combination comprising a driven member rotatable in one direction for moving the curtain towards its raised position and rotatable in the opposite direction for moving the curtain towards its lowered position, a reversible driving member for driving said driven member in both of said directions and including drive connection means for transferring driving forces from said driving to said driven member, safety means for stopping the rotational movement of said driven member in said opposite direction serving to halt the uncontrolled movement by gravity of the curtain to the lowered position upon failure of the counterbalance means, said safety means including relatively movable, confronting first and second friction members, said second friction member being drivable in both directions by said drive connection means, cam means including a cam follower arranged on said driven member and cooperative with said second friction member, said cam means being operative in response to uncontrolled rotation of said driven member by gravity movement of the curtain to urge said second friction member into frictional engagement with said first friction member serving to halt the rotation of said driven member in said opposite direction, said cam means being maintained in the inoperative condition in response to movement of said driven member by said driving member.
2. The subject matter of claim 1 wherein said friction members are concentrically arranged with said driven member, said second friction member being radially expandable, and said cam means serving to expand said second friction member into frictional engagement with said first friction member.
3. The subject matter of claim 2 wherein said second friction member is provided with a gap in its periphery, ramp portions on either side of said gap, said cam follower being disposed in engagement with said ramp portions.
4. The subject matter of claim 2 wherein said second friction member includes two, arcuately spaced, internally projecting dogs alternately engageable by said drive connection means for rotating said second friction member in synchronism with said driving member.
5. In a rolling door operating mechanism including a rollable curtain mountable for movement between raised and lowered positions and counterbalance means providing a bias against movement of the curtain to its lowered position, the combination comprising a rotatable member having a mechanical connection with the rollable curtain for rotation in opposite directions respectively in response to movement of the curtain to different ones of said positions, a stationary brake drum arranged concentrically of said rotatable member, radially expandable, brake band means mounted within said brake drum for movement into and out of the frictional engagement with said brake drum, said brake band and drum when in frictional engagement being effective to prevent the rotational movement of said member in said opposite direction serving to halt the uncontrolled movement by gravity of the curtain to the lowered position upon failure of the counterbalance means, a driving member mounted for angular movement between two operating positions relative to said rotatable member for driving the same, means interconnecting said brake band, rotatable, and drive members and rendering said driving member operative to rotate said brake band and rotatable member in opposite rotational directions respectively upon movement of said drive member to its said operating positions, cam means arranged on said rotatable member, brake band expanding means cooperable with said cam means to expand said brake bank into frictional engagement with said brake drum in response to rotation of said rotatable member by said curtain through said mechanical connection.
6. The subject matter of claim 5 wherein said brake band expanding means includes ramp portions arranged on said brake band on either side of the gap in its periphery, a cam follower carried on said cam means and projecting radially outwardly for cooperative engagement with said ramp portions.
7. The subject matter of claim 6 wherein said interconnecting means comprises arcuately spaced apart driving surfaces arranged on one of said members and diametrically oppositely extending shoulders arranged on the other two of said members for alternate engagement with said driving surfaces.
8. The subject matter of claim 5 wherein said interconnecting means includes a crescent shaped body on said drive member and means on said brake band and rotatable member defining drive shoulders cooperable with said body for rotating said brake band and rotatable member.
Description:
BACKGROUND OF THE INVENTION
This invention relates generally to operating mechanisms for rolling doors and more particularly to novel safety clutch devices for driving and braking the travel of a counterbalanced rolling door curtain upon malfunction or disablement of the counterbalance mechanism.
Rolling doors consist of an articulated curtain which is adapted to be raised and lowered to open or close an aperture or doorway. The curtain is rolled about or unrolled from a barrel mechanism which is rotatably mounted adjacent the top edge of the opening. As the barrel is rotated, the curtain is payed off from it to close the door, or rolled around it to open the door. To counterbalance the weight of the articulated curtain, a coiled, torsion spring is mounted within the barrel mechanism. Energy is stored in the spring upon unrolling the curtain from the barrel and energy is released from the spring when the curtain is again rolled around the barrel.
To insure that the articulated curtain will not fall to the lowered position upon failure of the counterbalance mechanism, it is desirable that a safety device be included in the operating mechanism. It is also desirable that the safety mechanism halt overwinding of the curtain, should for some reason the forces in the counterbalance mechanism overpower the restraining forces in the operating system. Rolling doors may include either or both a hand or motor actuated operating mechanism as exemplified by U.S. Pat. Nos. 3,134,273 and 3,007,342. In view of the use of both manually and motor actuated operating mechanisms, it is desirable that a safety device for the purposes above outlined be includable in either arrangement.
SUMMARY OF THE INVENTION AND OBJECTS
In summary, the invention concerns a rolling door operating mechanism for raising and lowering a rolling door of the type which includes a rotatable axle, a barrel having a counterbalance means cooperating with the axle, and a curtain adapted to be rolled onto and off of the barrel. The improvement therein which comprises a rotatable driving member in the operating mechanism and a rotatable driven member coaxially arranged with respect to the driving member. Connection means on the driving member extends axially therefrom to be received by the driven member so that the same may be rotated bidirectionally by said driving member. A safety clutch, including a stationary clutch support, is provided and comprises a brake drum rigid with the support, and coaxially arranged with said driving member. A brake band is arranged within said brake drum and means are provided on said brake band cooperable with said connection means serving to rotate said brake band with said driving member in the normal condition. Cam means are provided on said driven member cooperable with cam follower means disposed between said cam and a gap in the brake band. Should the counterbalance mechanism fail, relative motion created thereby between the cam means and the brake band serves to urge said cam follower means to expand said brake band against said brake drum, halting rotation of said operating mechanism.
It is a general object of the invention to provide an improved operating system for a rolling door having a counterbalanced barrel wherein novel safety features are provided in the drive system to arrest door movement upon failure of the counterbalance system.
Another object is to provide a safety device of the type described which can be mounted directly on the shaft of the counterbalanced barrel.
Another object is to provide a safety clutch for incorporation in a rolling door operating mechanism of either the manually operated or motor operated variety.
Another object is to provide in a rolling door operating mechanism a safety device preventing overwinding on the counterbalanced barrel of the articulated curtain due to overtensioning of the counter balance mechanism.
Additional objects and features of the invention will appear from the following description in which the preferred embodiments are set forth in detail and illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view illustrating a rolling door operating mechanism containing the safety clutch of the present invention.
FIG. 2 is a fragmentary front elevational view of the mechanism and safety clutch shown in FIG. 1.
FIG. 3 is an enlarged, cross-sectional view taken along the line 3--3 of FIG. 1, the chain guard being omitted for clarity.
FIGS. 4 and 5 are each cross-sectional views taken along the line 4--4 in FIG. 3, these figures illustrating two of the operational modes of the safety clutch device.
FIG. 6 is an exploded perspective view of the safety clutch device of the present invention.
FIG. 7 is a side elevational view illustrating a rolling door operating mechanism containing a second form of safety clutch of the present invention.
FIG. 8 is a fragmentary, front elevational view of the mechanism and safety clutch device shown in FIG. 7.
FIG. 9 is an enlarged cross-sectional view taken along the line 9--9 of FIG. 7.
FIGS. 10 and 11 are each cross-sectional views taken along the line 10--10 in FIG. 9, these figures showing two operational modes of the safety clutch device of the present invention and;
FIG. 12 is an exploded perspective view of the safety clutch device of the second form of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The first embodiment of our safety clutch for inclusion in a rolling door operating mechanism is shown in FIGS. 1-6 and includes a support bracket 11 which serves as a mounting for the rolling door 12 and the operating mechanism 13 which includes the hand chain mechanism 14. Two support brackets 11 are mounted on the wall 16 on the opposite sides of the opening formed by the door jambs 17 and near the lintel level 18 so that the rolling door can be raised above the lintel level. Mounting can be accomplished by an suitable means such as by fastening the bracket 11 to the wall angles 19 by means of the bolts 21. The wall angle can be fastened to the wall plate 22 by any suitable means such as screws or bolts.
The rolling door 12 may be of conventional construction wherein a main shaft 24 is suitably journaled in the brackets 11, and a barrel 26 is fixed to the shaft 24 and is coaxially aligned with the same. For counterbalancing, within the barrel there is mounted a coiled torsion spring 27. The torsion spring is suitably anchored in the barrel, as by a fastening clamp 25, so that when the barrel is rotated clockwise as viewed in FIG. 1, the spring 27 is energized, and deenergized when the barrel is rotated counterclockwise. A curtain 28 is mounted upon the barrel 26. The curtain may comprise, for example, an arrangement of interlocking slats fabricated from a suitable material such as cold-rolled steel, or a grille constructed as disclosed in U.S. Pat. No. 2,940,520 issued on an application by Harold W. Cookson, Jr., and Russell Wardlaw. The subject mechanism is also useful on vertical lift and sectional doors as well as most all types of rolling doors. The sides of the curtain 28 are adapted to run in curtain guides 29, which may be fastened to the wall angles 19 by any suitable means such as bolts. The tops of the guides are well flared at 31 to facilitate entry of the curtain. The entire curtain barrel assembly is covered by a hood 32 which can be fabricated from sheet steel and attached to the brackets by means of bolts or sheet metal screws (not shown).
The main shaft 24 is adapted to be rotated by the hand chain mechanism 14 which consists of a hand chain loop 36 which has one end looped about and engaging the teeth on a chain sprocket wheel 37. The chain should be of sufficient length so that it can be reached with ease by a person standing on the floor near the door. A chain guard 33 is provided to prevent the hand chain 36 from jumping off the sprocket wheel 37 and may be attached to the bracket 11 by suitable means such as bolts 34. As shown in FIG. 3, the sprocket 37 is equipped with a bushing 40 and arranged on a shaft 38 which is fixidly secured to the support bracket 11, the shaft being equipped with a portion of a reduced section 39 received within the bracket and suitably welded thereto. A pinion gear 41 equipped with a suitable bushing 45 is drivingly connected to the sprocket 37 by means of an off-centered mounted drive pin 42 which is fixidly secured to the sprocket 37 and projects through a crescent of kidney shaped opening 43 (FIGS. 4 and 5) in the pinion 41. Each end of the opening 43 is provided with a circular seat 44 having a radius generally complementary to that of the drive pin 42 and the seats 44 are connected by uniformly spaced arcuate or curved walls 46 and 47, so that the pin 42 may traverse the slot smoothly in driving the pinion gear in either direction. Included on the pinion 41 and the support brackets 11 there is arranged a safety clutch 49, the details of which will be fully considered hereinafter. The sprocket 37, pinion 41, safety clutch 49 are held in operative position upon the shaft 38 by a collar 51 equipped with a set screw 52 for locking the collar of the shaft.
A main gear 56 is arranged on the main shaft 24 and is secured thereto by means of a key 57 and set screw 58. Thus, rotation of the sprocket wheel 37 in either direction will serve to drive the pinion 41 by means of the drive pin. The pinion, being in meshing engagement with the main gear 56, will serve to rotate the main shaft 24 and barrel 26 for raising or lowering curtain 28.
The details of the safety clutch 49 are shown clearly in FIGS. 3-6, and include a collarlike element or brake drum 61 fixidly secured as by welding to the support bracket 11, and coaxially arranged with the support shaft 38. A brake band 62 having an outside diameter complimentary to the brake drum inside diameter is disposed within the brake drum 61. When the brake band is rotated in the normal mode within the brake drum, there is a small amount of frictional force created by the rubbing surfaces of the brake band and drum. The brake band is provided with an axial slit or gap 63 affording spring action to the band. The brake band 62 is caused to rotate within the stationary brake drum 61 by engagement of the sprocket drive pin 42 with one or the other of two inwardly projecting dogs 64. Preferably the faces of the dogs 64 contacted by the drive pin are spaced apart a distance substantially equally to the arc between the curved seats 44 in the opening 43 of the pinion as measured along the same circle.
Integral with the pinion gear 41 is an axially extending cam body 66 which projects into the central portion of the brake band 62. A cam face 67 on one side of the cam body 66, in cooperation with two spaced retaining lips or ramps 68, 69 adjacent the axial gap 63 of the brake band, support and retain a cylindrical cam follower pin 71 as the pinion gear and brake band are rotated together by the drive pin 42. The retaining lips 68, 69 are shaped so as to provide ramplike surfaces inclined towards the gap 63, as shown in FIGS. 4 and 5.
OPERATION
Operation of the unit may now be briefly described as follows:
When the main gear 56 is rotated by the pinion gear in the normal operational mode, through operation of the hand chain unit 14, the cam follower pin 71 and cam drive pin 42, take the position depicted in FIG. 4. In this mode there is no relative motion between the pinion, cam, and brake band, all being driven by the sprocket drive pin 42. The cam follower pin 71 is somewhat free between the lips 68, 69 to move along the cam face 67 without falling off. Should the counterbalance torsion spring 27 become disengaged from the barrel 26 permitting the weight of the curtain 28 to seek to rotate the main gear 56, the safety clutch assumes a braking mode, shown in FIG. 5, furnishing a braking action. In the transition from the normal operational mode of FIG. 4 to the braking mode of FIG. 5 the normal friction force between the brake band and the brake drum has a clockwise rector as viewed in FIG. 5 and serves to prevent the brake band from rotating freely with respect to the drum in the direction of the counterclockwise arrow shown in FIG. 5. Thus the brake band becomes substantially stationary with respect to the brake drum as the drive pin 42 is moved by the pinion (surface 44) from engagement with the brake band drive dog 64. As the main gear seeks to rotate the pinion 41 and the cam body 66 in the direction of the arrow of FIG. 5 there is, momentarily, relative motion between the brake band and cam. The cam face 67 takes an angular relationship with respect to the gap 63 and the cam follower pin 71 is urged outwardly toward the gap 63 in the brake band and between the retaining lips 68, as shown in FIG. 5. The inclination of the cam face 67 serves to drive the cam pin forcefully between the retaining lips, tending to widen the gap, expanding the brake band into frictional engagement with the stationary brake drum, thus braking the operating mechanism to a halt. As long as the main gear tends to drive the pinion 41, the cam follower pin will attempt to wedge itself in the gap 63 maintaining the safety clutch in a braking condition as shown. The brake action is released upon rotation of the sprocket 37 whereby the drive pin is again brought into engagement with one of the two drive dogs 64 and the cam body of the pinion is rotated so the parts again assume the position shown in FIG. 4.
SECOND PREFERRED EMBODIMENT
The second preferred embodiment of our safety clutch for inclusion in a rolling door operating mechanism is shown in FIGS. 7-12 and includes a support bracket 76 which serves as a mounting for the rolling door 12, previously described, and the operating mechanism 77 which includes a motor unit 78 including a gear reduction unit 79. Two support brackets 76 are mounted on the wall 16 similar to the mounting of the support bracket 11. The rolling door 12 included in this embodiment includes the main shaft 24 supported with respect to the brackets 76 by a bearing assembly 81 and a bushing 80, FIG. 9, the bearing being fixedly secured by the bolts 82 of the bracket. The barrel 26 is secured to the shaft 24, as previously described, and there is mounted therein a coiled torsion spring 27 suitably anchored to the barrel to act as a counterbalance when the curtain 28 is unrolled. The curtain 28, curtain guides 29, and hood 32 may be all constructed and arranged as described previously.
The main shaft 24 is equipped to be rotated by the motor unit with gear reduction and to that end a main sprocket 83 is rotatably mounted on the shaft 24. The driving connection between the sprocket 83 and the main shaft 24 includes a cam member 86 mounted upon the shaft 24 and fixedly secured thereto by means of a key 87 and setscrews 88 (FIGS. 10-12). In cross section, the cam is generally tee shaped having diametrically oppositely extending arms 89 and 91, and shoulders 92, 93. The shoulders 92, 93 are adapted to be engaged alternately by the driving faces 94, 96 of a crescent or circular segment shaped member 97 mounted upon a spacer or sprocket plate 98. The fasteners 99 and 100 hold in a connected unit the segment 97, the sprocket plate 98, and the sprocket 83. Thus rotation of the main sprocket 83 serves to rotate the segment 97 into engagement with one of the other of the shoulders of the cam 86 for rotating the main shaft 24 in the selected direction.
A safety clutch 101 includes a stationary brake drum 102 rigidly secured as by welding to the support bracket 76, and a rotatable brake band 103 an outside diameter complimentary to the brake drum inside diameter disposed within the brake drum when the brake band 103 is located in the normal mode in the brake drum, as shown in FIG. 10, there is a small amount of traction force created by the rubbing surface of the brake band and drum. The brake and 103 is spreadable to act against the brake drum as a friction brake. The opposite free ends of the brake band are each equipped with retaining lips or ramps 106, 107 which, with the substantially planar cam face 108, serve as a retaining means for a cylindrical cam follower member or pin 109, as shown in FIG. 10.
The inside surface of the brake band is provided with inwardly extending projections or dogs 111 diametrically oppositely arranged, and adapted to be engaged by associated driving faces 94, 96 of the drive segment 97, as the shaft 24 is driven by the main sprocket.
The sprocket wheel 83, equipped with a bushing 110, and cam 86 are maintained in proper operative relation on the shaft 24 by a collar 113 which is held in place by a setscrew 114.
Operation of the second preferred embodiment may now be briefly described as follows:
Assume that the parts are in the position as indicated in FIG. 10, the normal position for driving, wherein the driving segment 97, fixed to the main sprocket 83, has one of its faces, 94, in driving engagement with shoulder 92 on the cam 86 and in driving engagement with the projection or dog 111. As these parts rotate there is no relative motion between the cam and brake band. The cam follower or pin 109 is retained between the lips 106, 107 and the cam face 108 as the brake band and cam follower pin rotate in a clockwise direction as seen in FIG. 10. Power is supplied for this purpose from the motor unit 78 through the sprocket chain 84, thus, the shaft 24 is driven to either wind or unwind the curtain in the normal situation.
Assume that the counterbalance torsion spring 27 became disengaged from the curtain barrel 26 and became ineffective as a suitable counterbalance. The weight of the curtain 28 would tend, if unrestrained, to rotate the main shaft 24. In this condition, referring particularly now to FIG. 11, the main shaft would tend to rotate counterclockwise, carrying with it the cam member 86 which in turn would urge the drive segment to disengage from the dog 111 of the brake band. There would then be relative motion between the cam and brake band. At the same time the cam face 108 would assume an angular relationship with respect to the brake band gap it confronts and urge the cam follower into firm engagement against the retaining lips 106, 107, spreading the brake band into frictional braking engagement with the brake drum. The greater the turning force of the main shaft upon the cam, the greater will be the wedging action of the cam follower 109, tending to spread the brake band. The result is a quick and effective braking to halt the tendency of the runaway lowering action of the curtain and preventing what could otherwise be a dangerous condition.
To release the brake effect, it is only necessary to apply driving power in either direction through the sprocket and to again place the driving segment in engagement with the dog 111 to rotate together the brake band and cam. The cam face is thereby angled away from the retaining lips of the brake band and the cam follower pin is once again loosely carried between the retaining lips and cam face.
It will be noted that the safety clutch-brake unit is operable in either direction, being that the pertinent parts are axially symmetrical in both embodiments disclosed herein. It will be further recognized that the subject brake is quick operating, being that the cam follower is driven into a wedging relationship with the brake band in less than one quarter of a revolution of the cam. It will be apparent from the above that there has been provided a safety clutch mechanism which may be incorporated in either manually operated or motor operated drive mechanisms for rolling doors. The safety clutch mechanism does not interfere with proper operation of the rolling door but is always available as a safety device in the event of a malfunction in the counterbalance system and further requires little or no maintenance to retain its intended operational characteristics.
This invention relates generally to operating mechanisms for rolling doors and more particularly to novel safety clutch devices for driving and braking the travel of a counterbalanced rolling door curtain upon malfunction or disablement of the counterbalance mechanism.
Rolling doors consist of an articulated curtain which is adapted to be raised and lowered to open or close an aperture or doorway. The curtain is rolled about or unrolled from a barrel mechanism which is rotatably mounted adjacent the top edge of the opening. As the barrel is rotated, the curtain is payed off from it to close the door, or rolled around it to open the door. To counterbalance the weight of the articulated curtain, a coiled, torsion spring is mounted within the barrel mechanism. Energy is stored in the spring upon unrolling the curtain from the barrel and energy is released from the spring when the curtain is again rolled around the barrel.
To insure that the articulated curtain will not fall to the lowered position upon failure of the counterbalance mechanism, it is desirable that a safety device be included in the operating mechanism. It is also desirable that the safety mechanism halt overwinding of the curtain, should for some reason the forces in the counterbalance mechanism overpower the restraining forces in the operating system. Rolling doors may include either or both a hand or motor actuated operating mechanism as exemplified by U.S. Pat. Nos. 3,134,273 and 3,007,342. In view of the use of both manually and motor actuated operating mechanisms, it is desirable that a safety device for the purposes above outlined be includable in either arrangement.
SUMMARY OF THE INVENTION AND OBJECTS
In summary, the invention concerns a rolling door operating mechanism for raising and lowering a rolling door of the type which includes a rotatable axle, a barrel having a counterbalance means cooperating with the axle, and a curtain adapted to be rolled onto and off of the barrel. The improvement therein which comprises a rotatable driving member in the operating mechanism and a rotatable driven member coaxially arranged with respect to the driving member. Connection means on the driving member extends axially therefrom to be received by the driven member so that the same may be rotated bidirectionally by said driving member. A safety clutch, including a stationary clutch support, is provided and comprises a brake drum rigid with the support, and coaxially arranged with said driving member. A brake band is arranged within said brake drum and means are provided on said brake band cooperable with said connection means serving to rotate said brake band with said driving member in the normal condition. Cam means are provided on said driven member cooperable with cam follower means disposed between said cam and a gap in the brake band. Should the counterbalance mechanism fail, relative motion created thereby between the cam means and the brake band serves to urge said cam follower means to expand said brake band against said brake drum, halting rotation of said operating mechanism.
It is a general object of the invention to provide an improved operating system for a rolling door having a counterbalanced barrel wherein novel safety features are provided in the drive system to arrest door movement upon failure of the counterbalance system.
Another object is to provide a safety device of the type described which can be mounted directly on the shaft of the counterbalanced barrel.
Another object is to provide a safety clutch for incorporation in a rolling door operating mechanism of either the manually operated or motor operated variety.
Another object is to provide in a rolling door operating mechanism a safety device preventing overwinding on the counterbalanced barrel of the articulated curtain due to overtensioning of the counter balance mechanism.
Additional objects and features of the invention will appear from the following description in which the preferred embodiments are set forth in detail and illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view illustrating a rolling door operating mechanism containing the safety clutch of the present invention.
FIG. 2 is a fragmentary front elevational view of the mechanism and safety clutch shown in FIG. 1.
FIG. 3 is an enlarged, cross-sectional view taken along the line 3--3 of FIG. 1, the chain guard being omitted for clarity.
FIGS. 4 and 5 are each cross-sectional views taken along the line 4--4 in FIG. 3, these figures illustrating two of the operational modes of the safety clutch device.
FIG. 6 is an exploded perspective view of the safety clutch device of the present invention.
FIG. 7 is a side elevational view illustrating a rolling door operating mechanism containing a second form of safety clutch of the present invention.
FIG. 8 is a fragmentary, front elevational view of the mechanism and safety clutch device shown in FIG. 7.
FIG. 9 is an enlarged cross-sectional view taken along the line 9--9 of FIG. 7.
FIGS. 10 and 11 are each cross-sectional views taken along the line 10--10 in FIG. 9, these figures showing two operational modes of the safety clutch device of the present invention and;
FIG. 12 is an exploded perspective view of the safety clutch device of the second form of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The first embodiment of our safety clutch for inclusion in a rolling door operating mechanism is shown in FIGS. 1-6 and includes a support bracket 11 which serves as a mounting for the rolling door 12 and the operating mechanism 13 which includes the hand chain mechanism 14. Two support brackets 11 are mounted on the wall 16 on the opposite sides of the opening formed by the door jambs 17 and near the lintel level 18 so that the rolling door can be raised above the lintel level. Mounting can be accomplished by an suitable means such as by fastening the bracket 11 to the wall angles 19 by means of the bolts 21. The wall angle can be fastened to the wall plate 22 by any suitable means such as screws or bolts.
The rolling door 12 may be of conventional construction wherein a main shaft 24 is suitably journaled in the brackets 11, and a barrel 26 is fixed to the shaft 24 and is coaxially aligned with the same. For counterbalancing, within the barrel there is mounted a coiled torsion spring 27. The torsion spring is suitably anchored in the barrel, as by a fastening clamp 25, so that when the barrel is rotated clockwise as viewed in FIG. 1, the spring 27 is energized, and deenergized when the barrel is rotated counterclockwise. A curtain 28 is mounted upon the barrel 26. The curtain may comprise, for example, an arrangement of interlocking slats fabricated from a suitable material such as cold-rolled steel, or a grille constructed as disclosed in U.S. Pat. No. 2,940,520 issued on an application by Harold W. Cookson, Jr., and Russell Wardlaw. The subject mechanism is also useful on vertical lift and sectional doors as well as most all types of rolling doors. The sides of the curtain 28 are adapted to run in curtain guides 29, which may be fastened to the wall angles 19 by any suitable means such as bolts. The tops of the guides are well flared at 31 to facilitate entry of the curtain. The entire curtain barrel assembly is covered by a hood 32 which can be fabricated from sheet steel and attached to the brackets by means of bolts or sheet metal screws (not shown).
The main shaft 24 is adapted to be rotated by the hand chain mechanism 14 which consists of a hand chain loop 36 which has one end looped about and engaging the teeth on a chain sprocket wheel 37. The chain should be of sufficient length so that it can be reached with ease by a person standing on the floor near the door. A chain guard 33 is provided to prevent the hand chain 36 from jumping off the sprocket wheel 37 and may be attached to the bracket 11 by suitable means such as bolts 34. As shown in FIG. 3, the sprocket 37 is equipped with a bushing 40 and arranged on a shaft 38 which is fixidly secured to the support bracket 11, the shaft being equipped with a portion of a reduced section 39 received within the bracket and suitably welded thereto. A pinion gear 41 equipped with a suitable bushing 45 is drivingly connected to the sprocket 37 by means of an off-centered mounted drive pin 42 which is fixidly secured to the sprocket 37 and projects through a crescent of kidney shaped opening 43 (FIGS. 4 and 5) in the pinion 41. Each end of the opening 43 is provided with a circular seat 44 having a radius generally complementary to that of the drive pin 42 and the seats 44 are connected by uniformly spaced arcuate or curved walls 46 and 47, so that the pin 42 may traverse the slot smoothly in driving the pinion gear in either direction. Included on the pinion 41 and the support brackets 11 there is arranged a safety clutch 49, the details of which will be fully considered hereinafter. The sprocket 37, pinion 41, safety clutch 49 are held in operative position upon the shaft 38 by a collar 51 equipped with a set screw 52 for locking the collar of the shaft.
A main gear 56 is arranged on the main shaft 24 and is secured thereto by means of a key 57 and set screw 58. Thus, rotation of the sprocket wheel 37 in either direction will serve to drive the pinion 41 by means of the drive pin. The pinion, being in meshing engagement with the main gear 56, will serve to rotate the main shaft 24 and barrel 26 for raising or lowering curtain 28.
The details of the safety clutch 49 are shown clearly in FIGS. 3-6, and include a collarlike element or brake drum 61 fixidly secured as by welding to the support bracket 11, and coaxially arranged with the support shaft 38. A brake band 62 having an outside diameter complimentary to the brake drum inside diameter is disposed within the brake drum 61. When the brake band is rotated in the normal mode within the brake drum, there is a small amount of frictional force created by the rubbing surfaces of the brake band and drum. The brake band is provided with an axial slit or gap 63 affording spring action to the band. The brake band 62 is caused to rotate within the stationary brake drum 61 by engagement of the sprocket drive pin 42 with one or the other of two inwardly projecting dogs 64. Preferably the faces of the dogs 64 contacted by the drive pin are spaced apart a distance substantially equally to the arc between the curved seats 44 in the opening 43 of the pinion as measured along the same circle.
Integral with the pinion gear 41 is an axially extending cam body 66 which projects into the central portion of the brake band 62. A cam face 67 on one side of the cam body 66, in cooperation with two spaced retaining lips or ramps 68, 69 adjacent the axial gap 63 of the brake band, support and retain a cylindrical cam follower pin 71 as the pinion gear and brake band are rotated together by the drive pin 42. The retaining lips 68, 69 are shaped so as to provide ramplike surfaces inclined towards the gap 63, as shown in FIGS. 4 and 5.
OPERATION
Operation of the unit may now be briefly described as follows:
When the main gear 56 is rotated by the pinion gear in the normal operational mode, through operation of the hand chain unit 14, the cam follower pin 71 and cam drive pin 42, take the position depicted in FIG. 4. In this mode there is no relative motion between the pinion, cam, and brake band, all being driven by the sprocket drive pin 42. The cam follower pin 71 is somewhat free between the lips 68, 69 to move along the cam face 67 without falling off. Should the counterbalance torsion spring 27 become disengaged from the barrel 26 permitting the weight of the curtain 28 to seek to rotate the main gear 56, the safety clutch assumes a braking mode, shown in FIG. 5, furnishing a braking action. In the transition from the normal operational mode of FIG. 4 to the braking mode of FIG. 5 the normal friction force between the brake band and the brake drum has a clockwise rector as viewed in FIG. 5 and serves to prevent the brake band from rotating freely with respect to the drum in the direction of the counterclockwise arrow shown in FIG. 5. Thus the brake band becomes substantially stationary with respect to the brake drum as the drive pin 42 is moved by the pinion (surface 44) from engagement with the brake band drive dog 64. As the main gear seeks to rotate the pinion 41 and the cam body 66 in the direction of the arrow of FIG. 5 there is, momentarily, relative motion between the brake band and cam. The cam face 67 takes an angular relationship with respect to the gap 63 and the cam follower pin 71 is urged outwardly toward the gap 63 in the brake band and between the retaining lips 68, as shown in FIG. 5. The inclination of the cam face 67 serves to drive the cam pin forcefully between the retaining lips, tending to widen the gap, expanding the brake band into frictional engagement with the stationary brake drum, thus braking the operating mechanism to a halt. As long as the main gear tends to drive the pinion 41, the cam follower pin will attempt to wedge itself in the gap 63 maintaining the safety clutch in a braking condition as shown. The brake action is released upon rotation of the sprocket 37 whereby the drive pin is again brought into engagement with one of the two drive dogs 64 and the cam body of the pinion is rotated so the parts again assume the position shown in FIG. 4.
SECOND PREFERRED EMBODIMENT
The second preferred embodiment of our safety clutch for inclusion in a rolling door operating mechanism is shown in FIGS. 7-12 and includes a support bracket 76 which serves as a mounting for the rolling door 12, previously described, and the operating mechanism 77 which includes a motor unit 78 including a gear reduction unit 79. Two support brackets 76 are mounted on the wall 16 similar to the mounting of the support bracket 11. The rolling door 12 included in this embodiment includes the main shaft 24 supported with respect to the brackets 76 by a bearing assembly 81 and a bushing 80, FIG. 9, the bearing being fixedly secured by the bolts 82 of the bracket. The barrel 26 is secured to the shaft 24, as previously described, and there is mounted therein a coiled torsion spring 27 suitably anchored to the barrel to act as a counterbalance when the curtain 28 is unrolled. The curtain 28, curtain guides 29, and hood 32 may be all constructed and arranged as described previously.
The main shaft 24 is equipped to be rotated by the motor unit with gear reduction and to that end a main sprocket 83 is rotatably mounted on the shaft 24. The driving connection between the sprocket 83 and the main shaft 24 includes a cam member 86 mounted upon the shaft 24 and fixedly secured thereto by means of a key 87 and setscrews 88 (FIGS. 10-12). In cross section, the cam is generally tee shaped having diametrically oppositely extending arms 89 and 91, and shoulders 92, 93. The shoulders 92, 93 are adapted to be engaged alternately by the driving faces 94, 96 of a crescent or circular segment shaped member 97 mounted upon a spacer or sprocket plate 98. The fasteners 99 and 100 hold in a connected unit the segment 97, the sprocket plate 98, and the sprocket 83. Thus rotation of the main sprocket 83 serves to rotate the segment 97 into engagement with one of the other of the shoulders of the cam 86 for rotating the main shaft 24 in the selected direction.
A safety clutch 101 includes a stationary brake drum 102 rigidly secured as by welding to the support bracket 76, and a rotatable brake band 103 an outside diameter complimentary to the brake drum inside diameter disposed within the brake drum when the brake band 103 is located in the normal mode in the brake drum, as shown in FIG. 10, there is a small amount of traction force created by the rubbing surface of the brake band and drum. The brake and 103 is spreadable to act against the brake drum as a friction brake. The opposite free ends of the brake band are each equipped with retaining lips or ramps 106, 107 which, with the substantially planar cam face 108, serve as a retaining means for a cylindrical cam follower member or pin 109, as shown in FIG. 10.
The inside surface of the brake band is provided with inwardly extending projections or dogs 111 diametrically oppositely arranged, and adapted to be engaged by associated driving faces 94, 96 of the drive segment 97, as the shaft 24 is driven by the main sprocket.
The sprocket wheel 83, equipped with a bushing 110, and cam 86 are maintained in proper operative relation on the shaft 24 by a collar 113 which is held in place by a setscrew 114.
Operation of the second preferred embodiment may now be briefly described as follows:
Assume that the parts are in the position as indicated in FIG. 10, the normal position for driving, wherein the driving segment 97, fixed to the main sprocket 83, has one of its faces, 94, in driving engagement with shoulder 92 on the cam 86 and in driving engagement with the projection or dog 111. As these parts rotate there is no relative motion between the cam and brake band. The cam follower or pin 109 is retained between the lips 106, 107 and the cam face 108 as the brake band and cam follower pin rotate in a clockwise direction as seen in FIG. 10. Power is supplied for this purpose from the motor unit 78 through the sprocket chain 84, thus, the shaft 24 is driven to either wind or unwind the curtain in the normal situation.
Assume that the counterbalance torsion spring 27 became disengaged from the curtain barrel 26 and became ineffective as a suitable counterbalance. The weight of the curtain 28 would tend, if unrestrained, to rotate the main shaft 24. In this condition, referring particularly now to FIG. 11, the main shaft would tend to rotate counterclockwise, carrying with it the cam member 86 which in turn would urge the drive segment to disengage from the dog 111 of the brake band. There would then be relative motion between the cam and brake band. At the same time the cam face 108 would assume an angular relationship with respect to the brake band gap it confronts and urge the cam follower into firm engagement against the retaining lips 106, 107, spreading the brake band into frictional braking engagement with the brake drum. The greater the turning force of the main shaft upon the cam, the greater will be the wedging action of the cam follower 109, tending to spread the brake band. The result is a quick and effective braking to halt the tendency of the runaway lowering action of the curtain and preventing what could otherwise be a dangerous condition.
To release the brake effect, it is only necessary to apply driving power in either direction through the sprocket and to again place the driving segment in engagement with the dog 111 to rotate together the brake band and cam. The cam face is thereby angled away from the retaining lips of the brake band and the cam follower pin is once again loosely carried between the retaining lips and cam face.
It will be noted that the safety clutch-brake unit is operable in either direction, being that the pertinent parts are axially symmetrical in both embodiments disclosed herein. It will be further recognized that the subject brake is quick operating, being that the cam follower is driven into a wedging relationship with the brake band in less than one quarter of a revolution of the cam. It will be apparent from the above that there has been provided a safety clutch mechanism which may be incorporated in either manually operated or motor operated drive mechanisms for rolling doors. The safety clutch mechanism does not interfere with proper operation of the rolling door but is always available as a safety device in the event of a malfunction in the counterbalance system and further requires little or no maintenance to retain its intended operational characteristics.