US3479924A

US3479924A - Piston type operator with power checking

Info

Publication number: US3479924A
Application number: US722649A
Authority: US
Inventors: Harold W Ferguson
Original assignee: Stanley Works
Current assignee: Stanley Works
Priority date: 1968-04-19
Filing date: 1968-04-19
Publication date: 1969-11-25
Anticipated expiration: 1986-11-25

Description

Nov. 25, 1969 H. w. FERGUSON 3,479,924

PISTON TYPE OPERATOR WITH POWER CHECKING 2 Sheets-Sheet l 4 Filed April 19, 1968 N R m m m M Mn N 1 w W w W O M W H m at 3 m 15 QM Z s Q M s w .wi

ATTORNEY Nov- 1969 H. w. FERGUSON PISTON TYPE OPERATOR WITH POWER CHECKING 2 Sheets-Sheet 2 I. la I j Filed April 19, 1968 United States Patent 3,479,924 PISTON TYPE OPERATOR WITH POWER CHECKING Harold W. Ferguson, New Hartford, Conn., assignor to The Stanley Works, New Britain, Conn., a corporation of Connecticut Filed Apr. 19, 1968, Ser. No. 722,649 Int. Cl. F01b 25/00; Fb 13/044, 15/20 US. Cl. 91165 11 Claims ABSTRACT OF THE DISCLOSURE A fluid powered door operator having a double acting piston and cylinder assembly, sources of fluid at different pressures, one supplying each end of the cylinder, and a fluid flow control valve in each supply line for controlling fluid flow to the cylinder. An operator control switch initiates the flow to the cylinder of fluid under full pressure. Cam operated switch apparatus, also associated with the valve structure, is adapted, after a predetermined movement of the piston, to admit fluid under positive pressure to flow against the then advancing side of the piston while continuing the full pressure to the other side, to power check the piston and a door attached thereto and to stop the door at a predetermined point in a short distance. An adjustable valve can be utilized for providing throttled fluid flow in one direction and unthrottled exhaust flow, increasing the precision and versatility of the design.

This invention pertains generally to operators for panel members such as doors which are movable relatively to their supporting structures, and particularly to the double acting piston type of operator for such panel members, having apparatus for power checking the associated mechanism and doors to a stop.

The disposition of a series of cylinder exhaust ports which are progressively isolated from the fluid confine in the cylinder downstream of the drive piston exemplifies one well-known means for gradually decelerating a fluid operated piston. This and other heretofore known means for de-energizing and stopping a high velocity piston and cylinder assembly such as is utilized for a door operator of the type described are relatively expensive to make; require considerable installation space; and fail to positively stop a moving object at a predetermined point and within a relatively short distance.

The present invention overcomes the above recited drawbacks of the heretofore available checking devices, with a novel power checking apparatus featuring pressurized fluid simultaneously bearing against upstream and downstream sides of a moving piston during braking phases of operator function.

An object of this invention is to provide a new and improved piston type panel operator.

Another object of this invention is to provide a piston type panel operator that introduces driving fluid downstream of the traveling piston for power checking the panel, thereby eliminating extra checking devices and reducing both unit bulk and cost.

Another object of this invention is to provide a bidirectional piston type high velocity panel operator that maintains positive control of high velocity motion and can be quickly de-energized and braked to a stop at a predetermined point of transit.

Another object of this invention is to provide a bidirectional piston type high velocity panel operator in which fluid under adjustable positive pressure is caused to flow first against one side of the piston for driving the same and subsequently, simultaneously with that flow,

3,479,924 Patented Nov. 25, 1969 ice also against the other side for retarding and stopping the advancing piston.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.

In the drawing:

FIG. 1 is a front elevation, partly schematic and partly broken away, showing a portion of the novel operator of the invention;

FIG. 2 is an enlarged front view, partly schematic, showing additional detail of the operator disclosed in FIG. 1;

FIG. 3 is an end view taken along line 3-3 of FIG. 2; and

FIG. 4 is an enlarged fragmentary front view, similar to FIG. 2, of an adaptation of the novel operator of the present invention.

One embodiment of the operator 70 of the invention is illustrated in association with a sliding door that is movably disposed between open and closed positions relatively to a passageway (not shown) in wall 102. Track 104, fixed to the wall above the passageway sup ports trolleys 106 which in turn are mounted on and support the door 100, and provide for smooth operation of the same. Drive arm engages one of the trolleys 106 and is appropriately attached to the operator 70 for drivingly linking the door thereto.

The novel operator 70 is shown in FIG. 2 during an opening stroke thereof, and includes a fluid cylinder 10, which is of uniform size along its length, having end ports 18 and 22, a double acting piston 14 reciprocably driven within the cylinder, and a piston rod 12 attached to said piston. Cylinder 10 is equipped with an upstream end cap 16, and the opposite end of the cylinder through which the rod 12 passes, is fitted with a downstream end cap 20 suitably apertured to guide the rod as it reciprocates within the cylinder 10.

During an opening stroke of the operator 70, pressurized fluid from source 24 is supplied to flow regulating three way valve 26, which is opened by means of operator switch 50 for supplying fluid to cylinder 10 to drive the piston 14 toward downstream end cap 20 and the door 100 toward its open position. When the switch 50 is positioned at A, energy from electrical source 48 flows through the switch and opens valve input port 30 so that fluid from source 24 flows therethrough and across output port 34 into conduit 44 for delivery to the upstream end of cylinder 10 through end port 18, whereafter it bears against the upstream side of piston 14 to drive the same as indicated above. Fluid is exhausted from the downstream end of the cylinder 10 during each opening stroke, through end port 22 in the cylinder 10, into conduit 46 and thence through valve 45 and a flow regulating three way valve 28 also associated with electrical source 48 and discharged therefrom during an opening stroke, via output port 36 and exhaust port 40 communicating therewith.

As piston 14 and piston rod 12 move along within the cylinder 10, camshaft 56 moves in step with the rod, carried by cross-link 58 attached to adjacent ends of the rod and shaft and externally of the cylinder. The opposite end of the shaft 56 is supported by traveler 60 riding on the cylinder to maintain uniform spacing between the said shaft and the cylinder. Cam 62 is so disposed upon the camshaft 56 that it contacts microswitch 52 at an adjustable time predetermined with respect to the position of the piston 14 in the cylinder 10. The microswitch 52 is closed upon contact with cam 62, and energy source 48 is connected therethrough with valve 28, shifting the same from its exhaust condition described above to its-driving condition in which the input port 32 and the output port 36 are brought into communication and the exhaust port 40 is closed. Positive pressure from source 24a shown as being separate from source 24, is now applied through conduit 42a, and the valve 28 so that positive pressure is applied simultaneously into both the upstream and downstream ends of the cylinder 10. The fluid thus delivered to the downstream end of the cylinder normally has greater pressure than that delivered to the upstream end to compensate for the reduction of effective area of the piston 14 caused by the piston rod 12. While separate fluid sources 24 and 24a having different pressure levels are shown, it is apparent that other arrangements for compensating for the different effective areas of the two sides of the piston could be used. The positive pressure delivered downstream of piston 14 opposes and quickly checks the motion of the piston, thus deenergizing and stopping the same and the door 100 linked thereto.

Cross-link 58 is adjustably disposed on piston rod 12; camshaft 56 is axially adjustably disposed in the crosslink; and the cam 62 is positionable along the camshaft 56. This arrangement of structure facilitates presetting the exact moment at which cam 62 will contact switch 52, close the same and introduce the flow of braking fluid to cylinder 10. That contact is normally set to occur slightly before the door is fully opened. Positive reduction of velocity of the piston and the door linked thereto is obtained, therefore, at a predetermined point of beginning the downstream injection of fluid after the optimum movement of the piston 14. Refinement of the duration of downstream injection of fluid can be accomplished by using different sizes and numbers of replaceable cam segments 66, thus controlling the time during which microswitch 52 is held closed by the cam 62. The cam is thus sized to hold the switch closed long enough to completely stop the advancing piston and therefore the door. Positive control of high velocity motion in a relatively short distance of piston and door travel is thus also readily achieved by the invention, and is further refined by the valve 45 which offers adjustable resistance to fluid flow. In the power checking direction of fluid flow, plug member 47 seats against stop 48 cutting off fluid flow through passage 49 so that fluid for checking passes through the valve only along passage 51. In the exhaust direction, flow through the valve is unthrottled as the plug 47 unseats and opens the conduit 49 so that fluid passes through both the conduits 49 and 51.

Once opened as described above, the door 100 will be held open by the operator 70 as long as both

valves

26 and 28 remain open, that is, with their input ports in communication with their output ports. In other words, after cam 62 contacts and closes microswitch 52, fluid from the common source 24 ordinarily will impinge upon both the upstream and downstream sides of piston 14 as long as switch 50 remains in A position, and therefore the door will be immobilized in the open position.

In order for the door 100 to be closed, the fluid in the upstream end of the cylinder must have an exhaust route. Shifting the operator switch 50 out of A position opens the needed route by closing the valve 26, whereupon it assumes its exhaust condition, and output port 34 communicates with exhaust port 38 so that fluid from the upstream end of the cylinder can vent through conduit 44, port 34 and thence through port 38. In this condition of the valve 26, input port 30 is closed off from fluid flowing through conduit 42.

Effective reversal and closing drive of the piston 14 and door 100 is achieved by placing the switch 50 in B position directly from A position, whereby valve 28 is opened, without respect to the condition of microswitch 52. That is, as the switch 50 is positioned at B, input port 32 and output port 36 are interconnected and fluid flows from source 24, through conduit 42 and the valve 28, through conduit 46 and downstream aperture 22, bearing against piston 14 and driving the same toward the upstream end of the cylinder 10 and the closed position of the door as valve 28 is closed to exhaust conduit through

ports

34 and 38. Suitable braking means, such as a check spring (not shown) contacting the door prior to completion of its return movement, could be installed to prevent the retracting piston from impacting at full velocity against the end cap 16.

The invention is shown in FIG. 4 adapted for bidirectional power checking, that is to say, power checking of the return or closing stroke in addition to power checking of the opening stroke. As has been disclosed above, power checking of the opening stroke is effected with appropriately disposed microswitch 52 and cam means 62. Power checking of the door upon the return stroke of piston 14 is provided by means of a second microswitch 54 and cam means 64, as shown. The traveler 60 maintains uniform camshaft-to-cylinder clearance, as in the FIG. 2 embodiment. With the switch 50 in A position, the operator 70 functions as indicated for the first embodiment: fluid passes through valve 26 to bias the upstream side of the piston 14, driving the piston, the camshaft 56 and the door 100 downstream toward the open position of the door. At the appropriate moment cam 62 contacts and closes microswitch 52, causing fluid to flow into the downstream end of the cylinder 10 and quickly brake the motion of the piston and door. Changing the switch 50 to B position causes valve 26 to shift to exhaust condition and also causes valve 28 to maintain fluid flowing to the downstream side of the piston 14, thus driving the piston and the door in reverse. In addition, in this embodiment, the bidirectional adaptation includes the microswitch 54 and the cam 64 so disposed relatively to each other and to the camshaft 56 that the cam 64 is adapted to contact and close switch 54 and thereby open the valve 26, causing fluid to flow against the upstream side of the piston 14, via conduit 44. This flow begins at the appro riate moment which is predetermined with respect to the position of the piston 14. during its return stroke in the cylinder 10. That moment occurs during the interval when driving fluid is still being injected in the downstream end of the cylinder 10. The

' timing of the fluid injection for return stroke braking is based on the same principle, and except for the cam 64, the switch 54 and the adjustable valve 43, which is identical to valve 45, is obtained with the same structure as is the opening stroke braking in the FIG. 2 embodiment. Normally, therefore, the injection of the braking flow upstream is timed to occur slightly before the door is fully closed. The effect of this braking flow is to quickly check the motion of the piston 14 and door 100 as the latter reaches its closed position. Control of the duration of the fluid flow which functions to check piston and door closing motion is achieved by using different sizes and numbersof replaceable cam'segments 68 for the cam 64, just as various segments '66 can be used for the cam 62. Moreover, with proper relative positioning of cam 62 with respect to microswitch 54 as well as microswitch 52, both microswitches may be actuated by a single cam '62.

In addition to controlling the operator 70, the switch 50 enhances smooth functioning of the mechanism by maintaining the valves opened as needed to first reverse and then sustain the drive, independently of the microswitch and cam operation of the valves. That is, as the cam 62 and switch 52 disengage after power checking during'an opening stroke of the operator, the switch 50 maintains the fluid flow. In the same. manner, as the cam 64 and switch 54 disengage after power checking during a closing stroke of the operator, the switch 50 maintains the fluid flow. The switch 50 always ensures, therefore, that the door 100 will be held open or closed depending upon whether itthe switchis left in A or B position.

The present invention thus provides means for quickly power braking or checking a high velocity fluid operated piston assembly at a predetermined point of the piston travel, and within a relatively short distance. The usually severe impacting forces experienced under high velocity conditions are nullified by de-energizing and stopping the piston with fluid introduced against the advancing side of the piston simultaneosuly with the flow of fluid driving the upstream side of the piston. The usual extra checking devices are thus eliminated and machining costs and the bulk of the apparatus are reduced. The operator is disclosed in a sliding door environment but is readily adaptable to other types of installation such as are used for swinging doors.

I claim:

1. A fluid powered door operator for controllably driving a door between open and closed positions comprising a cylinder having longitudinally spaced first and second ports for both receiving and exhausting driving fluid, a

fluid actuated piston movable within said cylinder between said ports under the driving force of the fluid, first and second fluid flow regulating valves associated with the first and second ports, respectively, for regulating the flow of fluid through the ports into and out from the cylinder, and means associated with at least the second fluid regulating valve for braking the travel of the piston as it approaches the second port, said means including a sensor for sensing the approach of the piston toward the second port and for opening the second valve to permit flow of fluid into the cylinder through the second port without interrupting fluid flow to the first port to thereby brake the travel of the piston by the simultaneous flow of fluid against both sides of the piston.

2. An operator as claimed in claim 1 in which the sensor includes a piston actuated cam and a cam actuated switch connected with and controlling the operation of the second valve.

3. An operator as claimed in claim 2 in which the cam is adjustably disposed relatively to the switch to ensure timely switch actuating contact by the cam as the piston approaches the second port, said cam consisting essentially of a plurality of replaceable cam segments facilitating change in the duration of contact between the cam and the switch.

4. An operator as claimed in claim 1 including a throttling valve communicating both with the second valve and the second port of the cylinder for providing resistance to fluid flow in one direction and affording full flow exhaust.

5. An operator as claimed in claim 1 wherein said throttling valve is adjustable.

6. An operator as claimed in claim 1 including apparatus for supplying one end of the cylinder with fluid at a pressure diflerent from that supplied to the other end, to compensate for the different effective areas of the piston created by the piston rod.

7. An operator as claimed in claim 1 including additional means associated with the first valve for braking the travel of the piston as it approaches the first port, said additional means including a sensor for sensing the approach of the piston toward the first port and for opening the first valve to permit flow of fluid into the cylinder through the first port without interrupting flow of fluid to the second port to thereby brake the travel of the piston by the simultaneous flow of fluid against both sides of the piston.

8. An operator as claimed in claim 7 in which the valves are movable between fluid flow and fluid exhaust positions and said sensors include cam operated switches responsive to the movement of the piston for independently controlling the movement of the valves into said positions.

9. An operator as claimed in claim 7 including valve control means for alternately controlling fluid flow through each of said valves independently of the braking means associated with the valves.

10. An operator as claimed in claim 7 including an adjustable valve communicating both with the first valve and the first port of the cylinder for throttling the fluid flow in one direction and providing unthrottled flow in the other direction.

11. An operator as recited in claim 7 wherein the sensor includes a cam mounted on a camshaft one end of which is connected to the piston rod and the other end of which is connected to a traveler slidably mounted on the cylinder for maintaining the camshaft in fixed position prallel to the piston rod.

References Cited UNITED STATES PATENTS 711,102 10/1902 Foote 91324 821,663 5/1906 Mitchell 91-465 2,578,894 12/1951 Maurer 914l5 3,007,454 11/1961 Joelson 91321 3,329,068 7/1967 Klaw 91399 PAUL E. MASLOUSKY, Primary Examiner US. Cl. X.R.