US3921416A

US3921416A - Spring bias for damper door of an air conditioning unit

Info

Publication number: US3921416A
Application number: US517975A
Authority: US
Inventors: Raymond J Murnane; Theodore S Bolton
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 1974-10-25
Filing date: 1974-10-25
Publication date: 1975-11-25
Anticipated expiration: 1992-11-25
Also published as: IN145341B

Abstract

A device for biasing a damper door covering the port of a partition separating the evaporator and condensing sections of an air conditioning unit comprises an over-center leaf spring. The spring is an open-ended element connected at one end to the partition on one side of the axis about which the damper door pivots and at its other end to the door on the opposite side of the axis. The axis is within the confines of the line of force between the ends of the spring and the spring itself when the damper door is in its closed position so that the bias force is at its maximum value. As the door is pivoted about its axis towards the open position, the line of force moves towards the axis so that the bias decreases as the door opens.

Description

United States Patent Murnane et al.

[ Nov. 25, 1975 1 1 SPRING BIAS FOR DAMPER DOOR OF AN AIR CONDITIONING UNIT [73] Assignee: Carrier Corporation, Syracuse, NY.

[22] Filed: Oct. 25, 1974 [21] Appl. No.: 517,975

3,831,395 8/1974 Levy 62/427 Primary Examiner-William J. Wye Attorney, Agent, or FirmJ. Raymond Curtin; Barry E. Deutsch [57] ABSTRACT A device for biasing a damper door covering the port of a partition separating the evaporator and condensing sections of an air conditioning unit comprises an over-center leaf spring. The spring is an open-ended element connected at one end to the partition on one side of the axis about which the damper door pivots and at its other end to the door on the opposite side of the axis. The axis is within the confines of the line of force between the ends of the spring and the spring itself when the damper door is in its closed position so that the bias force is at its maximum value. As the door is pivoted about its axis towards the open position, the line of force moves towards the axis so that the bias decreases as the door opens.

4 Claims, 5 Drawing Figures US. Patent Nov. 25, 1975 Sheet10f2 3,921,416

1 SPRING BIAS FOR DAMPER DOOR OF AN AIR CONDITIONING UNIT BACKGROUND OF THE INVENTION 1. Field of the Invention V v The present invention relates to air Conditioning units, and in particular to means for biasing ventilation and exhaust dampers disposed over ports in the partition separating a condenser and evaporator sections of such units.

2. Description of the Prior Art Air conditioning units such as room air conditioners generally include refrigeration circuits having an evaporator and a condenser. The unit is generally divided by a partition into an evaporator section and a condenser section. The unit is normally mounted with the evaporator section being adjacent the space being cooled by the unit and in communication with the air in that space, and the condenser section is in communication with outdoor air. Refrigerant flows through the refrigeration circuit and absorbs heat from the room air flowing through the evaporator section causing the refrigerant therein to evaporate and flow towards the condenser section. Refrigerant in the condenser section gives up absorbed heat to the outdoor air flowing over the condenser causing the refrigerant to condense. In addition to the capability of controlling the temperature of the air in the space being conditioned, it is often desirable to remove stale air from the space or to admit fresh, outdoor air to the space. This is accomplished in various air conditioning units by the provision of appropriately positioned ports in the foregoing partition which can be selectively opened and closed to control the flow of air between the evaporator and condenser sections. Although it is common to provide a port for exhaust air and a second port for ventilation air, it is entirely possible to provide but one of the foregoing ports.

Ports of the aforementioned type are usually located to make use of pressure differentials for forcing the air in the desired direction through the partition. Such pressure differentials are normally created by means of appropriate fans and blower wheels disposed in the respective sections. The use of such ports is known in the art, as evidenced by US. Pat. No. 2,986,016 which issued on May 30, 1961, to Gillham et al.

Damper doors are conventionally provided for selectively opening and closing exhaust and vent port doors in room air conditioners. An effective construction of damper doors of the foregoing type and the associated apparatus for selectively opening and closing the doors is disclosed in US. Pat. No. 3,823,574 which issued on July 6, 1974 to Theodore 5. Bolton. The latter patent discloses a pair of pivotally mounted damper doors which are biased towards the closed positions by compression springs connected at one end to the partition and at the other end to one of the doors. The doors are opened by means of a lever which selectively engages the doors and overcomes the bias of the respective springs.

SUMMARY OF THE INVENTION An object of the present invention is to bias the damper doors of air conditioning units towards their closed position in an approved manner.

A more specific object of the present invention is to provide a device for biasing a damper door of a room air conditionertowards its closed position in a manner I which assures strong closing of the dooryet which facilitates the opening thereof.

Another object of the present invention is to provide an economical spring for biasing a damper door towards its closed position while facilitating the opening of the door. 1

Another object of the present invention is to provide a spring of the preceding type which can be modified to also bias the damper door towards its open position after the door has been opened by a predetermined amount.

Another object of the present invention is to provide a spring of the foregoing type which is simple in construction, reliable in operation, and easy to fabricate and assemble.

Other objects will be apparent from the description to follow and from the appended claims.

The preceding objects are achieved'according to a preferred embodiment of the invention by the provision of an overcenter open-ended leaf spring connected at one end to the partition separating the evaporator and condenser sections of a room air conditioner on one side of the axis of pivotal movement of a damper door,'and at its other end to the damper door on the opposite side of the axis. When the damper door is in its closed position, the axis is within the confines of the line of force extending between the ends of the spring and the spring, and the spring bias is at its maximum amount. As force is exerted on the door to open the door from its port closing position, the line of force moves towards the axis so that the force required to open the door decreases as the door is opened. The spring can be so constructed and assembled on the partition and the door so that the line of force passes over the axis whereby the spring then biases the door towards its open position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a pictorial representation of a portion of the interior of a room air conditioner showing damper doors over the vent and exhaust ports in a partition in the unit, and the apparatus for operating the doors.

FIG. 2 is a pictorial representation of a spring according to the invention for biasing the damper doors towards their closed positions.

FIGS. 3 and 4 are top partial views of the apparatus shown in FIG. 1 with one of the damper doors in its open and closed positions respectively.

FIG. 5 is a schematic side view of a self-contained room air conditioning unit having dampers of the type described herein.

- DESCRIPTION OF THE PREFERRED EMBODIMENT The embodiment of the invention described below is adapted for use in a self-contained room air conditioning unit, although it is to be understood that the invention defines applicability in other forms .of air conditioning units. The air conditioning unit described below includes a wall or partition separating the unit into a condenser or outdoor section which communicates with the outdoor or external air, and an evaporator or indoor section which is in communication with the room being air conditioned. An exhaust port is defined in the partition wherein the pressure on the evaporator side of the partition is greater than that on the condenser side of the partition. and a vent port is provided at a section of the partition where the pressure on the condenser side is higher than that on the evaporator side. Thus. air can be exhausted from the room to the outdoors through the exhaust port by virtue of the pressure differential existing across that port. while fresh air can be vented into the room by virtue of the pressure differential existing across the vent port. A pair of doors are pivotally mounted adjacent each of the ports for opening and closing the ports. The doors are biased to their closed positions by over center springs according to the present invention. A rotatable lever can be provided having an arm for exerting force on the doors to effect their opening.

Referring now to the drawings. FIG. shows in schematic form a self-contained room air conditioning unit having appropriately placed exhaust and vent ports. The unit includes a condenser section in which are located a condenser 1 and a fan 3 for directing ambient air over the condenser coils as indicated by the arrow, and an evaporator section including an evaporator 5 and a blower wheel or other fan 7 for drawing room air over the evaporator coil and directing that air back into the room as indicated by the arrow. The two sections of the unit are separated and isolated by a partition or wall 9. The unit is adapted for installation in a room so that the evaporator section communicates with the room air while the condenser section communicates with the outdoor air. The condenser and evaporator are part of a conventional refrigeration circuit which also includes a compressor and an expansion device (not shown). with the evaporator serving to absorb heat from room air drawn over the evaporator coils by the blower which then returns the cooled air back into the room. The heat absorbed by the refrigerant in the evaporator is thereafter transferred to the air being blown across the condenser coils by fan 3. Partition 9 is located considerably closer to blower wheel 7 and to fan 3 so that the pressure P in the region of blower wheel 7 is less than the pressure P on the condenser side of partition 9. Both of the pressures P and P, are suction pressures and are thus below the ambient pressure P The pressure P above blower wheel 7 is higher than the ambient pressure and is also higher than the pressure P above fan 3 because of the relative characteristics of the two air moving devices. An exhaust port 13 is defined in wall 9 between the region of pressure P and the region of pressure P so that when port 13 is opened, air flows through the port into the condenser section. Similarly, a vent port 15 is defined in partition 9 between the region of pressure P and the pressure P so that when port 15 is opened. air flows from the condenser section into the evaporator section and thereafter into the room.

The remaining figures illustrate apparatus for controlling the opening and closing of ports 13 and 15. The apparatus depicted enables the alternate opening of one of the ports and permits the closing of both ports; however, the apparatus is not adapted to open both ports simultaneously, since this would have the undesir able effect of simply circulating air between the ports rather than transferring air to and from the room being air conditioned. An exhaust port door 17 has a portion 18 configured to cover and close exhaust port 13 and is mounted for pivotal movement about an axis XX by a pair of tabs 19 extending through wall 9 adjacent port 13. An open-ended, over-center leaf spring 21 connected-at one end to door 17 on one side of axis XX and at its other end to partition 9 on the other side of axis XX biases door 17 to its closed position. Spring 21 is shown in detail in FIG. 2, and includes a generally arcuate portion 23 having a generally straight, opposing end portions 24 which are inclined slightly towards each other. Portions 24 terminate in small hooks or tabs 25 which are adapted to extend through corresponding openings in exhaust door 17 and in bent back portion 26 of partition 9. A portion 27 of wall 9 is configured to enable the air conditioning unit to accommodate a control box 29 which contains the operating buttons or the like for the unit. A second tab 31 includes a first section 33 which is coplanar with portion 18, a second section 35 which is bent back transversely towards wall portion 27, and a third section 37 which is generally parallel to section 33. The function of tab 31 will be apparent from the description to follow. A gasket 39 fabricated from some suitable material such as urethane foam is advantageously applied to door portion 18 engaging the wall surface surrounding exhaust port 13 when the door is moved to its exhaust port closing position. The engagement of gasket 39 and the port edge enhances the degree to which the door seals the port against the passage of air. In order to prevent any materialswhieh could damage the air conditioning unit from passing through discharge port 13, a filter 41 can be affixed across the port. Filter 41 may comprise a common filtering material such as fine mesh screen.

Vent port 15 is disposed between condenser fan 3 and blower 7 to take advantage of the previously described pressure differential existing in this area. A vent port door 43 is mounted for pivotal movement to open and close vent port 15. Vent door 43 includes a vent port closing portion 45 which is dimensioned to shut port 15 to the passage of air. Means are provided for biasing door 43 to its closed position, and it is contemplated that a spring similar or identical to spring 21 be connected to door 43 and partition 9 for this purpose in a manner similar to spring 21. However, for the sake of clarity, the provision of such biasing means has been omitted with regard to door 45. For the purposes of this description, it should be assumed that spring means are provided for biasing door 45 about an axis parallel to axis XX towards its vent port closing position. Again, it may be assumed, that the operation of doors l7 and 43 can be coordinated so that the desired sequence of door opening and closing events may be readily obtained. A gasket 55 fabricated from an appropriate material such as urethane foam is attached to door 43 for engaging the wall surface around vent port 15 when door 43 is in its port closing position. A filter 57 which can be in the form of a fine mesh screen is advantageously provided across vent port 15 for preventing potentially damaging materials from passing through vent port 15 into the evaporator section of the air conditioning unit.

In order to effect the selective opening and closing of the two ports, an operating lever 61 is provided in the unit. Lever 61 is preferably a unitary piece which can be fabricated from molded plastic. and comprises an actuating arm 63 engageable with tab 31, and a control arm 65 having a manually engageable portion 67 for operating the lever.

Arms

63 and 65 extend transversely from a rotatable shaft 69 having a longitudinal axis of rotation Y-Y which is parallel to the axes of rotation of exhaust port door 17.

Actuating arm 63 includes at its end portion furthermost spaced from shaft 69,

cylindrical portions

51 and 71 which are engageable with tab 31 of exhaust door 17. Control arm 65 is angularly displaced from actuating arm 63 so that when the exhaust door is in its closed position, manually engageable portion 67 is centrally disposed in a slot 73 in the exterior of control box 29. In other words, the foregoing elements are arranged so that when the door is shut, control arm, 65 is movable left or right as shown in FIGS. 4 and 5.

When exhaust port door 17 is closed,

cylindrical portions

51 and 71 of actuating arm 63 are in engagement with parallel section 33 of the tab as indicated in FIG. 2. When control arm 65 is moved counterclockwise or to the right as indicated in the drawings, a force is exerted transversely on section 33 of tab 31 of the exhaust door, with the resulting torque causing door 17 to pivot about axis XX to open exhaust port 13. When control arm 65 has been so moved to a predetermined extent,

cylindrical portions

51 and 71 slide over section 35 onto section 37 as shown in FIG. 4. When this occurs, the apparatus remains in the condition shown in the drawing even after manual pressure is released from control arm 65. This occurs because the line of force FF extending between the ends of end portions 24 of spring 21 passes across the axis XX of door 17 as the door is pivoted from its closed position as shown in FIG. 3 to its open position as shown in FIG. 4. It can be seen from these drawings that spring 21 biases door 17 to its closed position until such time as the line of force FF of the spring crosses the axis XX. In addition, the maximum closing force exerted by spring 21 is exerted when the door is closed, and this force diminishes as the door is pivoted towards its open position. When arm 65 is moved clockwise,

portions

51 and 71 slide over section 35 onto section 33 and thereby exert a force on the tab to return the door to its port closed position.

As noted before, control arm 65 may be suitably designed to operate door 43 as well as door 17. Thus, clockwise movement of arm 65 will provide a force to open door 43 as well as close door 17. Similarly, counterclockwise movement of arm 65 will cause door 43 to close as well as door 17 to open. To further simplify construction of the air conditioning unit, a spring similar to spring 21 and a tab similar to tab 25 may be incorporated in conjunction with door 43.

Spring 21 is of an extremely simple construction, comprising a unitary member of an appropriate material such as spring stock. The part can be stamped on conventional equipment and should have a negligible cost. Installation of the part is extremely easy, merely requiring the insertion of tabs 25 into appropriate openings in the door and partition in which it is to be attached. The part is advantageously designed to be symmetrical so that it makes no difference which end is attached to the respective openings of the air conditioning unit. Furthermore, it is also advantageous to use the same spring designed for both the exhaust and vent port doors, whereby the cost of the individual springs is reduced and the likelihood of confusion is eliminated.

The invention has been described in detail with particular reference to a preferred embodiment thereof. but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

We claim:

1. In an air conditioning unit having a casing, a partition dividing the unit into an evaporator section and a condenser section, and a port extending through said partition for enabling the flow of air between the evap orator section and the condenser section, apparatus for selectively opening and closing said port, said apparatus comprising:

a door dimensioned to cover said port;

means for mounting said door for pivotal movement about an axis between port opening and port closing positions; and

an open-ended leaf spring for biasing said door to the port closing position, one end of said spring being attached to said partition on one side of said axis and the other end of said spring being attached to said door on the opposite side of said axis, the line of force of said spring extending between the ends of said spring and said spring surrounding said axis when said door is shut and said line of force shifting toward said axis as said door pivots towards the port opening position, whereby said bias decreases from a maximum value as said door is moved from the port closing towards the port opening position.

2. The invention according to claim 1 wherein said axis is outside the confines of said line of force and said spring when said door is in the door opening position. whereby said spring biases said door in the door opening position when said door is in said door opening po sition.

3. A control mechanism for selectively opening and closing a door dimensioned to cover a port provided in a partition between the evaporator section and condenser section of a refrigeration unit comprising:

spring means for biasing said door toward a port closing position, said spring means having one end connected to a selected portion of the refrigeration unit, fixed in position relative to said door, the other end of said spring means being connected to said door, a first force developed by said spring means acting on said door, when said door is in a closed position, to maintain intimate contact between said door and the portion of the partition defining said port and a second force developed by said spring means acting on said door, when said door is moved toward a port open position, to bias said door in said open position.

4. A control mechanism in accordance with claim 3 wherein the magnitude of the first force is greater than the magnitude of the second force developed by said

Claims

1. In an air conditioning unit having a casing, a partition dividing the unit into an evaporator section and a condenser section, and a port extending through said partition for enabling the flow of air between the evaporator section and the condenser section, apparatus for selectively opening and closing said port, said apparatus comprising: a door dimensioned to cover said port; means for mounting said door for pivotal movement about an axis between port opening and port closing positions; and an open-ended leaf spring for biasing said door to the port closing position, one end of said spring being attached to said partition on one side of said axis and the other end of said spring being attached to said door on the opposite side of said axis, the line of force of said spring extending between the ends of said spring and said spring surrounding said axis when said door is shut and said line of force shifting toward said axis as said door pivots towards the port opening position, whereby said bias decreases from a maximum value as said door is moved from the port closing towards the port opening position.

2. The invention according to claim 1 wherein said axis is outside the confines of said line of force and said spring when said door is in the door opening position, whereby said spring biases said door in the door opening position when said door is in said door opening position.

3. A control mechanism for selectively opening and closing a dOor dimensioned to cover a port provided in a partition between the evaporator section and condenser section of a refrigeration unit comprising: means for mounting said door for pivotal movement about an axis between port opening and port closing positions; and spring means for biasing said door toward a port closing position, said spring means having one end connected to a selected portion of the refrigeration unit, fixed in position relative to said door, the other end of said spring means being connected to said door, a first force developed by said spring means acting on said door, when said door is in a closed position, to maintain intimate contact between said door and the portion of the partition defining said port and a second force developed by said spring means acting on said door, when said door is moved toward a port open position, to bias said door in said open position.

4. A control mechanism in accordance with claim 3 wherein the magnitude of the first force is greater than the magnitude of the second force developed by said spring means.