Inlet Vane Damper

Abstract

An inlet vane damper having a rigid ring interconnecting the vane shafts for closing or opening the vanes simultaneously. A crank arm of spring material interconnects each shaft with the ring to tolerate minor variations in the movement of the various arms with respect to the ring to obviate the necessity for precision in the manufacture and assembly of the damper control elements.

Description

This invention relates to fluid control apparatus and more particularly, to a damper intended for use in carefully controlling the flow of a fluid to a fan or the like by means of a plurality of vanes extending radially across a damper opening. These devices are commonly referred to in the trade as "inlet vane" dampers.

The vanes of dampers of this type are mounted on rotatable shafts which extend radially across the damper opening. The vanes serve to close off the opening or, when partially open, admit the air in a swirling path of travel into a fan or other apparatus. The shafts are preferably interconnected by a common bar or member so that they may all be operated in unison by a single control device. The common bar takes the form of a circular ring member extending around the damper opening and connected to the respective shafts through torque arms. This requires that the arms and connecting structures be of precisely the same length and the arms must be situated in precisely identical geometric arrangements if the damper is to operate smoothly and efficiently. Further, the ring member has been required in previous constructions to be carefully guided along a fixed, circular path of travel. The member itself had to be precision manufactured wherein relatively close tolerances were adhered to so that the member would move freely relative to its fixed guides. Lost motion devices were utilized to accommodate for the swinging of the torque arms along paths of travel that were quite different from the circular path of travel of the common ring member.

All of the foregoing resulted in a damper which was quite costly to manufacture and relatively hard to maintain in good working order. Accordingly, it is the primary object of this invention to provide an inlet vane damper having novel structure connecting the separate shafts to the common ring member which automatically compensate for minor manufacturing and assembly imperfections so that the cost of the damper is reduced.

Another object of the invention is the provision of a damper in which the requirement for expensive and difficult to maintain ring guides is completely eliminated.

Still a further object of the present invention is the provision of an assembly of two dampers having interconnecting structure which permits the two separate dampers to be operated simultaneously by a single controller.

These and other important objects and advantages of this invention will be further explained or will be apparent from the following specification and claims, and from the drawings.

In the drawings:

FIG. l is a fragmentary, side elevational view of a fan equipped with a pair of inlet vane dampers constructed pursuant to the principles of this invention;

FIG. 2 is an end elevational view of the fan of FIG. 1, parts being broken away and shown in cross section to clarify the illustration of the construction;

FIG. 3 is an enlarged end elevational view of a connector, the ring and torque arm appearing fragmentarily, parts being broken away and shown in cross section to reveal details of construction;

FIG. 4 is an enlarged, fragmentary, vertical cross-sectional view through a damper embodying the principles of this invention, and showing the torque arm in side elevation;

FIG. 5 is a view similar to FIG. 4, but taken 90.degree. to the latter and showing the torque arm in end elevation;

FIG. 6 is a view similar to FIG. 5, but showing the relative position of the arm and ring when the vane shaft is in its fully rotated position;

FIG. 7 is a fragmentary, top plan view of the damper, the positions for the ring and torque arm when the shaft is in its fully rotated position appearing in dash lines; and

FIG. 8 i a view taken along line 8-8 of FIG. 7.

An inlet vane damper embodying the principles of this invention is broadly designated in the drawings by the reference numeral 10. Damper 10 is used for carefully controlling the flow of fluid such as air or the like. In FIGS. 1 and 2 of the drawing, damper 10 is shown installed at the inlet of a fan broadly designated 12, the latter having a second damper 14 identical to damper 10 installed on the second inlet of fan 12. Manifestly, dampers embodying the principles of this invention may be utilized in conduits or the like but, in the main, have been used for controlling the flow of air at the inlet of a fan. The damper comprises an annular frame member 16 having outwardly extending annular flanges 18 and 20 rigidly secured to member 16.

Flange 20 is adapted to be secured to a corresponding flange 22 forming a part of the inlet 24 of fan 12.

An inner frame ring 26 concentric with ring 16 is secured in the position illustrated in FIG. 2 by means of three braces 28 having opposite ends secured to members 16 and 26 respectively. A plurality of shafts 30 have opposite ends journaled in members 16 and 26 respectively and project radially across the frame opening defined by frame member 16 as illustrated in FIG. 2. Suitable bearings 32 and 34 are provided members 26 and 16 respectively so that each shaft is free to rotate about its longitudinal axis. A blade 36 is rigidly secured to each shaft 30 and the blades 36 are shaped to complementally close the damper frame opening when the respective shafts 30 are rotated to a predetermined position. Obviously, when the shafts are simultaneously rotated about their longitudinal axes, the blades are swung to positions of relative angularity with respect to the closed positions thereof thus permitting the flow of fluid through the damper opening. Manifestly, the degree of swinging between the fully closed position to the fully open position of the respective blades controls the effective size of the orifice through the frame opening thereby permitting careful regulation of the flow of fluid through the damper.

Each shaft 30 is provided proximal its outermost end with a torque arm 38 which is rigidly secured to its respective shaft by means of a collar 40. Arm 38 may be secured to collar 40 by any suitable means such as welding or the like. Further, the collar 40 is preferably adjustably secured to its respective shaft 30 by a setscrew (not shown) or the like. Arm 38 is constructed from relatively thin yieldable spring material such as spring steel or the like and has a considerably greater width dimension than its thickness dimension to permit bending of arm 38 toward or away from its respective shaft 38 and about an axis extending transversely of arm 38 along the width dimension of the latter. The relatively great width of the arm will likewise resist bending of arm 38 about an axis parallel to shaft 30 so that the arms 38 may be utilized for applying sufficient torque to rotate shafts 30 for adjustment of the positions of the damper blades 36.

An elongated continuous ring 42 constructed of rigid material such as steel or the like is disposed in circumscribing relationship around frame member 16 and between flanges 18 and 20. This ring is disposed outwardly beyond the arms 38 and is connected to the outer end of each arm 38 by means of a swivel fastener broadly designated 44. The fastener 44 is best illustrated in FIG. 3 and comprises a body 46 drilled to receive ring 42 therethrough. A bolt 48 is threadably received in body 46 as illustrated and extends into physical engagement with ring 42 for rigidly clamping body 46 to the ring 42. A ball 50 is integral with the innermost pointed end of body 46 and is complementally received within a socket 52 at the outermost end of a pedestal 54 having an inwardly projecting bolt 56 adapted to releasably secure the pedestal to its corresponding arm 38. The socket 52 has a restricted neck 58 which permits a wide range of swinging movement of body 46 with respect to pedestal 54 thereby presenting a universal joint between the arm 38 and ring 42.

The ring 42 may be constructed from an elongated rod bent in circular fashion, the opposite ends of the rod being interconnected by any suitable fastener (not shown) after the ring is installed on the damper in the position illustrated.

In use, one or more dampers 10 or 14 may be installed as shown in FIG. 1. A controller 60 such as an electric motor, solenoid or the like is operably coupled with one shaft 30 for rotating the shaft responsive to signals which may be sent to controller 60 from a remote source through an electric cable 62. The shaft 64 from the fan prime mover 66 may be received through the central opening 68 defined by the innermost frame member 26. In any event, member 26 is aligned with a corresponding tubular portion of the fan motor (not shown) or may be otherwise closed so that the effective orifice through the damper is controlled by blades 36.

Although controller 60 is illustrated coupled with damper 14, it will be understood that controller 60 might just as well be coupled with any of the shafts 30 of damper 10. In the assembly illustrated in FIG. 1, damper 14 is identical in construction with damper 10 and will not be described in detail. A flexible cable or shaft 70 has one end thereof secured to one of the shafts 30 of damper 14 and the other end of cable 70 is coupled with one of the shafts 30 of damper 10. This interconnects the shafts of the respective dampers so that rotation of a shaft of one damper causes a resultant identical rotation of the corresponding shaft of the other damper.

Any rotation of any of the shafts 30 causes a consequent swinging movement of its respective torque arm 38. Since each arm 38 is secured to ring 42, there must be a movement of the ring in response to the swinging of the torque arm. Obviously, since all of the torque arms for each damper are coupled with the common ring member 42, the swinging of one arm 38 results in a corresponding swinging of all arms 38.

Heretofore, inlet vane dampers have utilized a common ring member for interconnecting of torque arms so that the damper blades all move simultaneously and in corresponding directions and through corresponding distances. However, it has heretofore been necessary to provide elaborate guide rollers or other confining means to the ring to insure that it maintains a fixed circular path of travel to obtain the precision necessary in the movement of the blades. The necessity for precision guide means has also required that the ring itself be precisely constructed for movement through the guide means. Further, elaborate lost motion mechanisms have been required to permit the swinging of the torque arms through a fixed plane about the shafts 30 while the common ring moved on a different, circular path of travel.

It is to be pointed out at this juncture that the novel torque arms 38 which are connected to ring 42 by the universal connectors 44 obviate all necessity for such precisely constructed guide and lost motion mechanisms. The yieldability of the torque arms 38 permit the same to bend or deflect as a result of the rotation of the common ring member 42 about a fixed central axis responsive to the swinging of a torque arm 38. The deflection of the torque arm 38 as a result of the swinging of the arm 38 from an intermediate position shown in FIG. 7 to a position at the end of the path of travel for its corresponding blade (shown in dash lines in FIG. 7) is graphically designated by the reference numeral 72 in FIG. 8 This bending is a result, of course, of the tendency of the torque arm to rotate in a plane extending perpendicular to the axis of rotation of shaft 30 while the movement of ring 42 proceeds on the circular path of travel about its central axis. Obviously, the swinging of the torque arms 38 which are uniformly distributed around the damper will result in the shifting of the ring 42 toward or away from the respective shafts 30 as shown in dash lines in FIG. 7. The ring, however, automatically remains concentric to its initial position throughout its entire range of movement and this concentricity insures uniformity of movement of all of the blades as they are operated simultaneously upon movement of the ring 42. It is contemplated, of course, that the blades and connecting structures are of uniform size and are disposed in identical positions of angularity in the composite damper.

The swivel connection effected by fastener 44 is necessitated by virtue of the geometry of the interconnected ring, shaft and torque arm. Although the torque arm would normally rotate about its shaft in a fixed plane, the deflection of the torque arm results in such movement occurring in a curvilinear path. Were it not for the universal joint of the connector 44, a longitudinal twisting of the torque arm 38 would result. Such twisting is avoided with the ball and socket connection and the body 46 and pedestal 54 may assume relative positions throughout the entire range of movement as are necessary to prevent such longitudinal twisting of the torque arms 38.

Not to be overlooked is the fact that ring 42 need not be precisely constructed in the damper described herein. The deflection permitted by arms 38 permit ring 42 to free-float and follow the movement of the interconnected torque arms. The elimination of the necessity for a precisely constructed common ring member substantially minimizes the cost of dampers of this type.

Claims

I claim:

1. In a damper having a plurality of shafts extending radially across a damper opening, means mounting the shafts for rotation about respective longitudinal axes, a vane carried by each shaft respectively, each vane being disposed to block its corresponding portion of said opening when its shaft is rotated to a predetermined position, and control means operably coupled with said shafts for simultaneously rotating the latter to move the vanes toward or away from respective closed positions, said control means comprising:

a rigid annular member extending around the opening;

an operating crank for each shaft respectively, each crank including an elongated arm of substantially flat spring material projecting from its corresponding shaft and deflectable longitudinally toward said shaft to produce a biasing force toward said annular member; and

a ball and socket assembly pivotally coupling the member with each arm respectively, each ball and socket being disposed between the corresponding arm and the member in position for said biasing force to hold the ball against its corresponding socket, each assembly including means for securing the assembly to the member at a position longitudinally thereof bending the arm to produce said biasing force, whereby the biasing force holds the ball and socket against rattling and rotation of any of said shafts rotates the member about the central axis of the latter to simultaneously swing the arms for rotating the remaining shafts.

2. The invention of claim 1, wherein each of said arms comprises an elongated, substantially flat strip of spring steel, and means rigidly securing said strip to its corresponding shaft.

3. The invention of claim 2, wherein the width dimension of said arm is substantially greater than the thickness thereof to restrict the bending of the arm to a path of travel toward and away from said shaft.

4. The invention of claim 1, wherein is provided an assembly comprising a pair of said dampers, and herein is included a flexible shaft having its opposite ends rigidly coupled with a shaft of each respective damper, whereby all of said shafts of both dampers rotate together responsive to rotation of any of said shafts.

5. The invention of claim 4, wherein is provided power means operably coupled with one of the shafts of one damper for operating both of said dampers of the assembly.

6. The invention of claim 1, wherein said assembly securing means includes clamp means carried by each of said assemblies and shiftable along said member for adjustably securing the respective arms to the member at any desired position longitudinally of the member, whereby to permit adjustment of the magnitude of the biasing force on each assembly respectively.