US3699717A

US3699717A - Air door operator

Info

Publication number: US3699717A
Application number: US70848A
Authority: US
Inventors: Lloyd C Hedrick
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-09-09
Filing date: 1970-09-09
Publication date: 1972-10-24
Anticipated expiration: 1989-10-24

Abstract

A pivotal door is powered towards both open and closed positions by a shaft connected to a gear engaging a pair of rack members connected to double acting air cylinders inturn connected to a solenoid valve which is responsive to switches in the door carpet such that each of the air cylinders assist in both opening and closing the door. The operation of the door operator is buffered by the metering of oil between cylinders for the rack members having pistons thereon.

Description

Unite States Patent 5] Oct. 24, 1972 Hedrick [54] AIR 0R OPERATOR 3,447,423 6/ 1969 Henry ..92/68 X 7 Inventor: Lloyd C- Hedrick, 912 Washington 3,195,879 7/ 1965 BOl'ld et a1 ..49/264 X Pleasantville, Iowa 50225 I Primary Examiner-J. Karl Bell [22] Wed: Sept 1970 Attorney-Zarley, McKee & Thomte [2!] Appl. No.: 70,848

[57] ABSTRACT [52] US. Cl. ..49/264, 49/137, 49/ 334, A pivotal door is powered towards both open and 9/336, 60/52 CD closed positions by a shaft connected to a gear engag- [51 Int. Cl. ..E05i 13/00, E05f 15/04 ing a pair of rack members connected to double acting of Search air cylinders intum connected to a solenoid valve 60/52 57; 92/68 which is responsive to switches in the door carpet such that each of the air cylinders assist in both opening [56] References cued and closing the door. The operation of the door operator is buffered by the metering of oil between cylin- UNITED STATES PATENTS 4 ders for the rack members having pistons thereon. 3,040,717 6/1962 Rumsey ..92/68 X 3,056,573 10/ 1962 Matheson et al. ..92/68 X 9 Claims, 8 Drawing Figures 5 I: w I I /5 h 1 I 52 /Z II l I 36 l l I l il 5 l ,2 y 38 2". 4 I I I v a' I 26 1 l I -i I i l "/''/'"i" 'R 4Z5 60 7 7/ l l PATENTEDnm 24 m2 4/? COM/725E501? P5641419 To:

VAL v5 OPE N 2 5 Z MN mm L Wm m A w c M Z u 05 7 m Y mm AIR DOOR OPERATOR Automatic door openers heretofore used commercially have involved mechanical gear systems or hydraulically operated door openers. In each case the power train involves a substantially rigid application of power to the door during both opening and closing. Consequently, each operation of the door results in a sudden jolt to the door, operating mechanism and wall and floor structure. Additionally, if an object is hit by the door during its operation the forces through the door and operator are substantial and often times damaging to the door operator mechanism.

The door operator mechanism of this invention is totally air operated at low pressures and includes two double acting pistons connected to rack members engaging opposite sides of a gear on a shaft connected to the door such that when the door is either opened vor closed both air cylinders are applying rotational torque to the output shaft to give smooth operation. If an obstruction is hit by the door the air will permit the door to yield to the object without damage to the door, operator system or other supporting structure. Moreover, when the door operation begins towards either the open or closed positions the action will be smooth and fluid-like with a minimum of stress and strain on all moving parts.

The force transfer vehicle in the door operator system is air which is compressible as compared to oil in a hydraulic system which operates in a rigid mechanical manner. The pair of rack members operating on the gear result in even pressure on the bearings, gear and shaft eliminating many failures that would otherwise occur if the push and pull action on the gear occurred only on one side.

This invention consists in the construction, arrangements and combination of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in the claims, and illustrated in the accompanying drawings in which:

FIG. 1 is a fragmentary elevation view showing the air door operator in use on a door assembly.

FIG. 2 is an enlarged cross-sectional view of the air door operator taken along line 2 2 and showing the door in two different open positions.

FIG. 3 is a side elevational view of the air door operator.

FIG. 4 is a cross-sectional view taken along line 4 4 in FIG. 3.

FIG. 5 is a exploded perspective view of the rack and air piston rod.

FIG. 6 is a schematic of the air door operator system; and

FIG. 7 is an electrical schematic of the air door operator system, and

FIG. 8 is an alternate schematic of the air exhaust system.

The air door operator system of this invention is referred to generally in FIG. 1 by reference numeral 10 and is located in a header 12 above a doorway 14 in a wall 16. A door 18 is pivotally connected to the doorway 14 and the header for pivotal movement about the axis of a power shaft 20 in the door operator 10. In the entrance to the doorway an open carpet 22 is provided and on the exit side of the doorway 14 is a safety carpet 24.

The air door operator system as seen in FIGS. 2, 3 and 4, includes a housing 26 in the metal channel header 12. The output shaft 20 is provided with gear teeth 28 on opposite sides thereof separated by reduced radii peripheral surfaces 30. The teeth 28 are exposed into passageways 32 in which rack members 34 having teeth 36 move in engagement with the teeth 28. A piston head 40 is provided on the outer end of the rack members 34 and has a cross-sectional area close to the cross-sectional area of the passageway 32. The outer edges of the teeth 36 are in a plane inwardly offset from the peripheral surface of the piston 40 adjacent the gear teeth 28 such that the gear can turn sufficiently to provide a 90 opening of the door 18 without the gear teeth 28 hitting the piston 40.

A tapered groove or slot 44 extends from the outer end of the passageways 32 to the gear shaft 20. An end plate 46 is secured by bolts 48 to the housing 26 and includes a passageway 50 for placing the passageways 32 in communication with each other. An adjustable valve 52 is provided for varying the amount of hydraulic oil 54 that is permitted to flow between the rack member passageways 32.

Each of the rack members 34 include a T-shaped slot 56 extending transversely of the rack members longitudinal axis to receive a T-shaped male member 58 on the inner end of a piston rod 60. The piston rods 60 extend from double acting air cylinders 62 which include outwardly extending threaded portions 64 threadably engaging the housing 26 in alignment with the passageways 32 to secure the cylinders 62 to the housing 26 as best seen in FIG. 4.

The double acting cylinders 62 include pistons 68 having

air chambers

70 and 72 on opposite sides thereof. A pair of

crossover lines

74 and 76 interconnect the chamber 70 of one cylinder 68 with the chamber 72 of the other cylinder 68 as seen in FIG. 2. It is seen that the pistons 68 always move in opposite directions due to their connection with the shaft 20 through the rack members 34.

The

crossover lines

74 and 76 are in turn connected to L-

members

80 and 82, respectively, which are connected to

air lines

84 and 86 having valves 88. The

air lines

84 and 86 are in turn connected to a four-way solenoid valve 90 in communication with an air compressor 92 through an air regulator valve 94 in an air line 96. An exhaust muffler 98 is attached to the fourway valve 90.

The electrical schematic for the air door operator system is shown in FIG. 7 and includes the four-way solenoid valve 90 controlled by a conventional automatic door opening relay box 100 in turn connected to the open and

safety carpets

22 and 24 respectively.

Thus in operation it is seen that upon stepping on the open carpet 22 a switch 102 in the carpet is closed thereby energizing the relay box 100 which in turn operates the solenoid valve 90 to direct air to opposite ends of the air cylinders 62 to turn the shaft 20 in a counterclockwise direction as viewed in FIG. 2 to open the door to the 90 position shown by the dash lines. It is seen that air will pass through the line 86 and apply air pressure on the right side of the top piston as viewed in FIG. 2 while applying pressure on the left side of the bottom piston through the crossover line 76. Simultaneously air is being exhausted from the left side of the top cylinder in FIG. 2 through the crossover line 74 connecting with the line 84 also receiving exhaust air from the right-hand side of the bottom cylinder and this air returns to the four-way valve to be returned to the atmosphere through the exhaust muffler 98. When the door 18 is being closed the operation is reversed by the switch 102 returning to its normally open position thus causing the relay box 100 to actuate the solenoid valve such that air is then directed through the line 84 to the right-hand side of the bottom piston in FIG. 2 and the left-hand side of the top piston through the crossover line 74. Similarly, air is being exhausted from the righthand side of the top cylinderand the left-hand side of the bottom cylinder through the line 86 to the four-way valve and out the exhaust muffler. Thus it is seen that uniform pressures are applied to both sides of the output shaft 20 through the rack members 34 to provide a smooth and even torque to the shaft.

Additionally it is seen that the air drive is buffered by the metering of oil between the passageways 32 in which the rack members 34 move. Thus, as the top piston 40 on the rack member 34 moves to the left, as seen in FIG. 4, oil is permitted initially to escape rearwardly along the rack member due to the enlarged cross-section of the elongated slot 44 whereby door movement begins instantly and later comes to a gentle stop as the piston 40 of the top rack member 34 moves further to the left due to the amount of oil escaping past it becoming less and slowing down the speed of the door movement towards an open position. When the door is being closed the same sequence will occur with regard to the other metering piston thereby providing for instant starting and smooth gentle stopping. It is also seen that the gear and rack members are self-oiled by the circulation of oil and the oil is metered back and forth through the passageway 50 to further smooth out the operation of the door operator. If desired, the oil metering may be stopped completely and the operation of the door as well by the closing off of the passageway 50 by operation of the valve 52. The speed of the door operation may also be controlled by the adjustment of the air flow control valves 88.

The safety mat 24 is seen to include a switch 110 connected to the relay box 100 and this switch serves to either hold the door open when it is actuated or to hold the door closed in a conventional manner.

The air door operator can operate at very low air pressure on the order of 40 p.s.i. It is seen that additionally a very little volume of air is used. The inherent resiliency of the air door operator eliminates the need for springs to wind up or compress to close the door as is required by some door operators. The rack and gear assembly are so constructed that a short stroke will cause a 90 turn of the door. In case of failure of the power system the door may be manually operated by overriding the air pressure. The speed of the door is controlled by the flow control valves both as to the rate of air flow on the intake and the exhaust for each of the cylinders. The metering and dampening or buffering provided by the V-shaped slots in the rack member passageways permit the door to start instantly and bring the door to a smooth and gentle stop.

The air power for the door makes the operation on recycling much smoother such that when the door is on the way closed and another person starts through the door the air valve switches from the closed to open position and air will compress preventing the door from opening again with the sudden violence associated with hydraulic or gear driven doors which causes damage and maintenance problems. It is seen that there is a uniform load on the bearings and shaft since pressures are even on both side of the shaft due to the pushing and pulling on the air cylinders connected to the rack members in turn connected to the output gear.

An alternate air exhaust system is illustrated in FIG.

8 which permits the door to more instantaneously move towards an open position upon the open carpet 22 being actuated. The air being exhausted from the air cylinder 62 through the

conduit

74 and 76 passes through a Humphrey quick dump valve 88A commercially available, into a relatively larger diameter conduit 149 which is connected to an expansion chamber 150 having a needle valve in its outlet conduit 153. Thus the air escapes instantaneously and the door opens without any hesitation upon the open carpet 22 being stepped upon by a person passing through the door. Adjustment of the needle valve 152 controlling the exhaust of the expansion chamber to the atmosphere will give the fine adjustment necessary for a particular door system. The remaining components and operation illustrated in the schematic of FIG. 6 remain the same since any hesitation in the closing of the door will not be objectionable. The needle valve 152 allows the exhaust chamber 150 to accumulate air as the door moves towards the end of its open movement and thus cushions the door at its fully opened position.

I claim:

1. An air powered hydraulic controlled door operator comprising, a pivotal door,

a rotatable output shaft connected to said pivotal door for opening and closing said door,

a gear coupled to said output shaft and rack members engaging said gear on opposite sides thereof,

said gear and rack members are disposed in a housing and said rack members each have a piston head moveable in hydraulic fluid cylinders in communication with each other through a restricted passageway,

a separate double acting air cylinder connected to each of said rack members,

an air control system coupled to each of said air cylinders and connected to an air pressure supply means,

crossover conduits placing opposite ends of said air cylinders in communication with each other whereby said air control system at times selectively places opposite ends of said air cylinders in communication with said air pressure means and at other times places the other ends of said air cylinders in communication with said air pressure means such that at all times each of said air cylinders are operating in opposite directions and are cooperating to turn said output shaft in a common direction,

a foot door mat including a normally open switch operatively connected to said air control system whereby said air cylinders will be operated to operate said hydraulic cylinders to open said door under air pressure upon said switch being closed and close said door under air pressure upon said switch being opened with said hydraulic cylinders controlling the opening and closing of the door.

2. The structure of claim 1 wherein each of said rack members includes a loose fitting coupling between it and the piston rod of the associated air cylinder.

3. The structure of claim 2 wherein said coupling includes a T-shaped element matingly received in a T- shaped slot such that engagement and disengagement occurs through lateral movement therebetween relative to the longitudinal axis of said rack members and piston rods.

4. The structure of claim 1 wherein said control system includes a four-way valve for operatively reversing directions of operation of said air cylinders.

5. The structure of claim 1 wherein said cylinders each include a tapered longitudinally extending slot in the side walls thereof increasing in size towards said gear for passing a smaller amount of fluid past said pistons the farther said pistons are moved from said gear.

6. The structure of claim 5 wherein said restricted passageway includes an adjustable valve.

7. The structure of claim 6 wherein said gear includes teeth only on opposite sides for engagement with the teeth on said rack members and the outer plane of the rack teeth is transversely inwardly offset from the outer peripheral edge of said pistons adjacent said gear and said shaft has a smaller radius along the periphery between said teeth thereon than the radius to the outer periphery of said shaft teeth.

8. The structure of claim 1 wherein said air control system includes a four-way solenoid valve electrically connected to said switch.

9. The structure of claim 8 wherein said door operator is located in a header above said door and said output shaft extends downwardly into engagement with said door.

Claims

1. An air powered hydraulic controlled door operator comprising, a pivotal door, a rotatable output shaft connected to said pivotal door for opening and closing said door, a gear coupled to said output shaft and rack members engaging said gear on opposite sides thereof, said gear and rack members are disposed in a housing and said rack members each have a piston head moveable in hydraulic fluid cylinders in communication with each other through a restricted passageway, a separate double acting air cylinder connected to each of said rack members, an air control system coupled to each of said air cylinders and connected to an air pressure supply means, crossover conduits placing opposite ends of said air cylinders in communication with each other whereby said air control system at times selectively places opposite ends of said air cylinders in communication with said air pressure means and at other times places the other ends of said air cylinders in communication with said air pressure means such that at all times each of said air cylinders are operating in opposite directions and are cooperating to turn said output shaft in a common direction, a foot door mat including a normally open switch operatively connected to said air control system whereby said air cylinders will be operated to operate said hydraulic cylinders to open said door under air pressure upon said switch being closed and close said door under air pressure upon said switch being opened with said hydraulic cylinders controlling the opening and closing of the door.

3. The structure of claim 2 wherein said coupling includes a T-shaped element matingly received in a T-shaped slot such that engagement and disengagement occurs through lateral movement therebetween relative to the longitudinal axis of said rack members and piston rods.