Aircraft toilet flush valve

• US 4,783,859 A
• Filed: 11/04/1987
• Issued: 11/15/1988
• Est. Priority Date: 09/24/1985
• Status: Expired due to Fees

• Current Assignee: MAG Aerospace Industries Incorporated
• Original Assignee: Monogram Industries, Inc.
• Inventors: Allen, Jon E., Jung, Anna M., Rozenblatt, Mike M.
• Primary Examiner(s): Recla, Henry J.
• Assistant Examiner(s): Sholl, Linda J.
• Application Number:
  US07/119,203
• Time in Patent Office: 377 Days
• Field of Search: 4/316, 4/321, 4/323, 4/431, 4/432, 4/433, 4/434, 4/435, 4/DIG. 13, 4/DIG. 17, 4/DIG. 16, 251/129.12, 251/9, 251/4, 251/80, 251/77
• US Class Current: 4/316
• CPC Class Codes: B64D 11/02 Toilet fittings of general application A47K
• CPC Class Codes: E03F 1/006 Pneumatic sewage disposal systems; accessories specially adapted therefore
• CPC Class Codes: F16K 3/0281 Guillotine or blade-type valves, e.g. no passage through the valve member
• CPC Class Codes: F16K 31/04 using a motor
• CPC Class Codes: Y10S 4/13 Toilet having deformable trap

Abstract

A flush valve is provided for opening and closing a drain connecting a toilet bowl to a waste holding tank maintained at a partial vacuum. The flush valve is located external to the drain and comprises a pinch or nip mechanism surrounding a flexible section of the drain and an electro-mechanically operated actuator for moving the pinch mechanism to close the drain by pinching it shut or to open the drain by pulling it apart. The actuator includes a motor for moving a piston in opposite directions, and a cylinder having one end connected to the pinch mechanism and another end containing an enclosure. The piston is retained and reciprocable a limited distance within the enclosure, and a spring is interposed within the enclosure to provide biasing means between the piston and the cylinder. The spring has sufficient stiffness relative to the force needed to shut the flexible drain section, in the absence of an obstruction, so that the flexible drain section may be fully closed without compression of the spring by the piston. However, when the flexible drain section is nipped shut, or if an obstruction is encountered, the spring will be compressed within the enclosure by the piston, causing operation of a switch to deactivate the motor and prevent motor stalling and damage to the valve. A manually operable shut-off flush valve also is provided, comprising a plate slidable through a coupling in the drain line to bring an opening in the plate in or out of registration with the drain line to open or close it, respectively.

Claims

1. A flow control assembly for controlling flow through a drain from a toilet bowl to a waste tank maintained at a partial vacuum, the control assembly comprising:

(a) a flexible drain section connected in line in the drain;

(b) a nip mechanism movably connected to said drain section for nipping said flexible drain section shut to stop flow and for dilating said drain section open to enable flow;

(c) a drive motor having

an output shaft selectively driven in opposite directions by said drive motor, and

control means for starting and stopping said drive motor; and

(d) linkage means connecting said output shaft to said nip mechanism for nipping said flexible drain section shut on shaft motion in one direction and for dilating said flexible drain section open on shaft motion in the opposite direction, said linkage means including

lost motion means for permitting motion of said output shaft over a limited range of travel without opening or shutting of said nip mechanism,

resilient biasing means connected with said lost motion means for preventing operation of said lost motion means until said linkage means encounters a predetermined level of force resisting motion of said nip mechanism, said biasing means having sufficient stiffness relative to the force needed to shut said flexible drain section in the absence of an obstruction that said drain section is nipped fully to the shut condition without operation of said lost motion means, application of force beyond that necessary to fully shut said flexible drain section overcoming said biasing means to enable operation of said lost motion means, and

stop means actuated by said lost motion means and operably connected to said control means for stopping said motor when said linkage means applies a predetermined level of force to said nip mechanism and said lost motion means has travelled a predetermined distance.

2. The flow control assembly of claim 1, wherein said nip mechanism comprises a pinch knife assembly having an upper pinch knife on one side of said flexible drain section and a lower pinch knife on an opposite side of said flexible drain section, the pinch knife being connected together by a pivot arm so that movement of the upper pinch knife in the one direction towards the lower pinch knife nips said flexible drain section shut, and movement of the upper pinch knife in the opposite direction away from the lower pinch knife opens said flexible drain section.

3. The flow control assembly of claim 1, wherein said linkage for connecting said output shaft to said nip mechanism comprises:

a cylinder having one end connected to said nip mechanism and the other end having an enclosure;

a piston having one end connected to said output shaft and the other end being retained and reciprocable a limited distance within the enclosure of said cylinder; and

a spring interposed within the enclosure of said cylinder between said cylinder and the other end of said piston, said spring being in a compressed condition when said flexible drain section is closed,

motion of the output shaft in the one direction pushing said piston against said spring and said cylinder and moving said nip mechanism to close said flexible drain section, and motion of the output shaft in the opposite direction pulling said cylinder away from the drain and moving said nip mechanism to open said flexible drain section.

4. The flow control assembly of claim 3, wherein said spring has a spring force greater than the force necessary to close said flexible drain section in the absence of an obstruction.

5. The flow control assembly of claim 1, wherein said resilient biasing means is a spring having a spring force that is greater than the force necessary to close said flexible drain section in the absence of an obstruction.

6. The flow control assembly of claim 1, wherein said control means includes means connected to said drive motor for adjusting the rotational speed of said output shaft to enable said nip mechanism to open and close said flexible drain section at different rates.

7. The flow control assembly of claim 1, wherein said drive motor is a D.C. motor and said control means includes means for connecting the positive and negative terminals of said drive motor to provide dynamic breaking to counteract motor inertia when said stop means stops said drive motor.

8. A toilet valve assembly for controlling the flow of waste from a toilet bowl to a waste holding tank through a drain, comprising:

(a) a flexible drain section in line in the drain;

(b) a pinch mechanism for movement in a first direction by an actuating force to dilate said flexible drain section to an open position for enabling the flow of waste through the drain, and for movement in a second direction by the actuating force to pinch said flexible drain section to a closed position for stopping the flow of waste through the drain;

(c) an actuator for applying the actuating force in the first and second direction to said pinch mechanism, said actuator having

a drive motor connected to a source of power,

an output shaft connected to said drive motor selectively driven in the first and second directions,

a first member connected to said output shaft,

a second member connected to said pinch mechanism, and

a resilient member interposed between said first member and said second member; and

(d) switch means actuated by movement of said first member relative to said second member and operably connected to said actuator for connecting and disconnecting power to said motor, said switch means disconnecting power to said motor after said actuator has applied a predetermined level of force to said pinch mechanism and the resilient member has been compressed a pre-determined amount.

9. A flush valve for opening and closing a drain connecting a toilet bowl to a waste holding tank, comprising:

(a) a pinch knife assembly having an upper pinch knife on one side of the drain and a lower pinch knive on an opposite side of the drain, the pinch knives being connected by a linkage so that movement of the upper pinch knife away from the lower pinch knife opens the drain, and movement of the upper pinch knife towards the loewr pinch knife closes the drain;

(b) a first member having an upper end with an enclosure and a lower end connected to said pinch knife assembly for movement with the upper pinch knife;

(c) a second member having a lower end retained within the enclosure, said second member being moveable a limited distance with respect to said first member;

(d) a resilient member within the enclosure of said first member and positioned between the lower end of said second member and said first member;

(e) reciprocating means connected to an upper end of said second member for reciprocating said second member in opposite directions, movement of said second member in a first direction pulling said second member, said first member and the upper pinch knife to open the drain, movement of said second member in a second opposite direction pushing said second member against said resilient member, said first member and the upper pinch knife to close the drain; and

(f) switch means for actuating and disabling said reciprocating means in response to movement of said second member, said switch means being actuated to disable said reciprocating means by movement of said second member relative to said first member and by application of force to compress said resilient member a predetermined amount.