US3534500A - Hydraulic power unit for an automatic door opener - Google Patents

Description

Oct. 20, 1970 N. ETAL Y 3,534,500

HYDRAULIC PCWER UNIT FOR AN AUTOMATIC DOOR OPENER Filed Dec. 18, 1968 3 I l I l Q Q I I F l I I v o A N I NV EN To Z 5 en vma/vo H. 80 sum 6- EQR6E 4 Even/w kg w MMIKMM-QM YATTORNEYS 3,534,500 HYDRAULIC POWER UNIT FOR AN AUTOMATIC DOOR OPENER Raymond H. Boehm, 3411 McArthur Place, and George L. Boehm, 3520 Standish Lane, both of Racine, Wis.

Filed Dec. 18, 1968, Ser. No. 784,808 Int. Cl. Ef 13/04, /04

US. Cl. 49-264 11 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Door openers of the type contemplated herein use a single acting hydraulic piston and cylinder assembly to open the door with a return spring being used to close the door. The door conventionally should be fully opened within one and a half seconds and should remain open for approximately three and a half seconds. The hydraulic cylinder conventionally requires a charge of four cubic inches of hydraulic fluid at a pressure of 500 psi. in order to open the door under positive control. The hydraulic fluid supply unit capable of providing the above volume of hydraulic fluid at the specified pressure in one and one half seconds requires a one-third horsepower motor which is housed in a very large housing. Where gas-oil pressure accumulators have been used to provide the hydraulic fluid for the piston-cylinder assembly, an even bulkier unit is required. The resupply switch for these accumulators operates in the 500 p.s.i. range and is not very sensitive. A rather large fluid reservoir is therefore necessary in order to assure suflicient hydraulic fluid in the accumulator to operate the door until the resupply switch starts the motor to operate the pump.

SUMMARY OF THE INVENTION The self-contained door opener of the present invention provides a sufficient charge of hydraulic fluid to freely open a door using a unit of substantially reduced size. This is accomplished by utilizing the diaphragm of a gasoil accumulator to actuate a pump switch on the initial movement of the diaphragm to start the supply pump, rather than depending on a pressure change requiring discharge of a volume of fluid. Whenever a diaphragm is referred to, it will be understood that any switch actuating structure solely responsive to a predetermined position of the boundary defined by the gas-oil medium such as a piston or other equivalent is included. The pump will then operate during the entire time that it takes to open and close the door. Since the door will be opened for approxiamtely five seconds, a one-eighth horsepower pump can operate the door and resupply the accumulator with a full charge at the prescribed pressure. This self- 3,534,500 Patented Oct. 20, 1970 contained operator can be readily adapted to various sizes and weights of doors, since it will always operate at the pressure set in the gas chamber because the diaphragm must return to its initial position before the pump switch is opened.

Other objects and advantages will be apparent from the following detailed description when read in connection with the accompanying drawings, in which:

FIG. 1 is a top view of the door operator shown connected to the hydraulic piston and cylinder actuator for an automatic door.

FIG. '2 is a side elevation view partly. in section of the self-contained operator.

FIG. 3 is a view taken on line 3-3 of FIG. 2 showing the recirculation path from the pump to the reservoir.

FIG. 4 is an enlarged view partly in section of the solenoid control valve.

DESCRIPTION OF THE INVENTION Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. The scope of the invention is defined in the claims appended hereto.

Referring more particularly to the drawing, the selfcontained door operator 10 of this invention is shown in FIG. 1 connected to open a typical door 12 which is mounted in frame 14 to swing about pivot post 16 through an are indicated by arrow 18. A single acting spring return type hydraulic piston and cylinder assembly 20 is used to swing the door 12 about post 16 by means of a rack 22 connected to a piston 24 in assembly 20 and a gear 26 connected to the post 16. A spring 28 in cylinder 30 is used to bias the piston 24 and door 12 to a closed position in frame 14. Conventional treadle switches 32 and 34 are provided on each side of the door 12 to initiate the operation of the door operator 10.

More specifically, the self-contained door operator 10 includes a housing 36 divided by a wall 38 into a fluid reservoir 40 and a pressure chamber 42. A working fluid, i.e. oil, is pumped by means of a pump 54 from the reservoir 40 to the assembly 20. The pump 54 is not capable of fully opening the door in the required time and additional hydraulic fluid must be combined with the fluid supplied by the pump 54 to open the door fully in the required time. This additional fluid is accumulated within a compartment 44 formed at one end of chamber 42 by means of a resilient diaphragm 46 secured to the open end of chamber 42 by end wall 48. The volume of working fluid accumulated in compartment 44 should be sufficient when combined with the volume of fluid supplied by pump 54 to completely charge the cylinder 30 in assembly 20 and open the door 12 in the required time interval. In a conventional system the cylinder volume is approximately four cubic inches and must be fully charged in one and one-half seconds. This can be accomplished with a one-eighth horsepower pump which is capable of supplying four cubic inches of oil at 500 p.s.i in three seconds. The accumulator, therefore, must provide two cubics inches of oil at 500 p.s.i. in one and one-half seconds.

The fluid in compartment 44 is pressurized by maintaining a compressible medium such as gas or air under a substantially constant pressure in chamber 42. Gas or air under pressure is admitted to chamber 42 by means of a one-way type check valve positioned in passage 52 in wall 38. Any type of one-way valve may be used for check valve 50, such as a tire type needle valve as shown in the drawing. The fluid in compartment 44 should be maintained at a pressure of 500 psi. to assure positive opening of the door 12. However, this pressure may be varied according to the size and weight of the door. The air in chamber 42 is brought up to this pressure by admitting air under pressure through valve 50 and is maintained at that pressure by the valve 50.

The accumulator compartment 44 is charged with fluid by means of the pump 54 which is mounted on the inside of end wall 56 and driven by a motor 58 mounted on the outside of end wall 56. The pump 54 is provided with an inlet 60 located in the reservoir 40 and an outlet 62 connected to a passage 64 in the end wall 56. Hydraulic fluid is pumped from the reservoir 40 through inlet 60 to a flow line 66 connected to the passage 64 and to passages 68 and 70 in end wall 48. Reverse flow of fluid from the accumulator 44 back through flow line 66 and pump 54 is prevented by means of a check valve provided in passage 64. This valve may be a ball type check valve of the type shown in my copending application Ser. No. 782,632, filed Dec. 10, 1968.

The flow of fluid from the door operator 10 to the piston and cylinder assembly 20 is controlled by means of a solenoid activated valve 72 which is electrically connected to respond to the actuation of treadle switches 32 and 36. The control circuit valve 72 is not shown since it only requires a power source connected between the treadle switches 32 and .34 and valve 72. Fluid flows from the pump 54 and compartment 44 through passages 68 and in end wall 48 through pipe 74 connected to the control valve 72 and from the control valve 72 through pipe 76' to the cylinder 20. Referring to FIG. 4, the solenoid control valve 72 includes a housing 80 having a central passage 82. A spool valve 84 is provided in the passage 82 and is moved by means of a solenoid 86 against the bias of a spring 88 to complete a flow path from conduit 74' through ports 90 and 92 in the housing 80 to conduit 76. When the solenoid 86 is de-energized, the spring 94 will move the spool valve 84 to the end of the passage 82 closing port 90 and completing a flow path through pipe 76, ports 92 and 08 to return conduit connected to a return passage 102 in end wall 56 to reservoir 40.

As soon as the fluid in compartment 44 starts to discharge, the motor 54 is started by means of a switch 104 which senses the motion of diaphragm 46. More particularly, the switch 104 is mounted on a bracket on end wall 48. The switch is actuated by means of a switch actuating rod 106 mounted for reciprocal motion in an opening 108 in mounting bracket 110 and secured to a plate 112 on the resilient diaphragm 46. The switch 104 is connected to the motor 58 by means of leads 114 and 116 connected to sealed terminals and 117, respectively, provided in the wall of the housing 36. The circuit between the terminals 115 and 117 and motor 58 is not shown since it only requires a power source connected between the terminals 115 and 117 and the motor 58. When the plate 112 moves from abutting engagement with the bracket 110, the switch 104 will be closed to energize the motor 58 to pump fluid from the reservoir 40 into the accumulator compartment 44. The motor 58 will continue to run until the plate 112 on the diaphragm 46 is moved back into abutting engagement wtih the support bracket 110. If, for any reason, the pump motor 58 should continue to run after the accumulator compartment 44 has been recharged, the excess fluid will flow through bypass passage 120 provided in the end wall 56 between passages 64 and 102. A one-way check valve 122 is provided in passage 120 to restrict the flow of fluid until the pressure of the fluid exceeds 500 psi.

Because of the structure of the accumulator, the pressure required to open switch 104 may be adjusted merely by altering the pressure behind diaphragm 46. Since the air chamber is closed, the pressure must return to the pre-set pressure in order that the diaphragm. may return to the switch opening position. Within the capacity of the pump, if more torque is needed, more air is added to raise the operating pressure. If less torque is desired, air is bled from the chamber. This uniquely simple adjustment is a. consequence of the novel structure described.

What is claimed is:

1. A self-contained door operator to open a framed door which is biased to a closed position in the frame and opened by a hydraulic door actuator, said operator comprising a housing having a reservoir for hydraulic fluid,

means for pumping fluid from said reservoir to the actuator,

means within said housing to accumulate a predetermined charge of hydraulic fluid,

means for controlling the discharge of fluid from said accumulator to the door actuator, and

means for actuating said pumping means eflective immediately and solely upon the initial discharge of fluid from the accumulator and to maintain said actuation until the initial quantity of fluid is restored to the accumulator.

2. A self-contained door operator according to claim 1 wherein said accumulating means includes a chamber within said housing and a resilient diaphragm separating said chamber into a gas pressure chamber and a fluid chamber.

3. A sel f-contained door operator according to claim 1 wherein said actuating means includes a switch responsive to the discharge of fluid from said accumulating means.

4. A self-contained door operator according to claim 1 wherein said pumping means is connected to said accumulating means.

5. A door operator for opening a framed door which is equipped with treadle operated control switches and opened by a hydraulic piston and cylinder assembly, said operator comprising a housing having a fluid supply reservoir and a gas liquid pressure chamber,

a resilient diaphragm dividing said chamber into a gas pressure compartment and a fluid compartment, means to supply fluid from said reservoir to said fluid compartment,

means to maintain a predetermined pressure in said gas-pressure compartment,

means in said gas-pressure compartment responsive to the movement of said diaphragm to control said supply means, and

means responsive to the actuation of the treadle switches to control the flow of fluid from said fluid compartment to the piston and cylinder assembly.

6. A door operator according to claim 5 wherein said responsive means includes a switch having a switch actuator positioned to respond to the motion of said diaphragm.

7. The sub-combination comprising an accumulator having a fixed initial volume of working fluid,

a volume of compressible medium at a pre-set initial pressure,

there being a boundary between said working fluid and said compressible medium,

a switch,

and means effective to actuate said switch responsive solely to the position of said boundary.

8. The device of claim 7 including a motor adapted to utilize said working fluid,

a source of additional working fluid capable of achieving said initial pressure and connected to supply said fluid to said accumulator and said motor,

and means to release fluid from said accumulator to said motor.

9. The device of claim -8 in which said switch controls 2,276,338 said source of working fluid. 3,026,576

10. The device of claim 8 further comprising 5 References Cited UNITED STATES PATENTS I. KARL BELL, Primary Examiner U.S. Cl. X.R.

Images