US3358563A

US3358563A - Air cylinder cycling apparatus

Info

Publication number: US3358563A
Application number: US470697A
Authority: US
Inventors: Selden T Williams
Original assignee: Scovill Inc
Current assignee: ROSTRA ENGINEERED COMPONENTS Inc A CORP OF CT; Scovill Inc
Priority date: 1965-07-09
Filing date: 1965-07-09
Publication date: 1967-12-19
Anticipated expiration: 1984-12-19

Description

Dec. 19, 1967 s. T. WILLIAMS 3,35

AIR CYLINDER CYCLING APPARATUS Filed July 9, 1965 2 Sheets-Sheet 1 Dec. 19, 1967 s.- T. WILLIAMS 3,358,563

AIR CYLINDER CYCLING APPARATUS Filed July 9, 1965 2 Sheets-Sheet 2 Fig.2.

United States Patent M 3,358,563 AIR CYLINDER CYCLING APPARATUS Selden T. Williams, Middlebury, Conn., assignor to Scovili Manufacturing Company, Waterbury, Conn., a corporation of Connecticut Filed July 9, 1965, Ser. No. 470,697 1 Claim. (Cl. 91-246) This invention relates to air cylinder cycling apparatus to control the automatic reciprocation of a piston for repetitive motive applications. It is intended to operate continuously as long as connected to a supply of air under pressure.

Devices of this general class are in common use where the cycling of the piston through its operating stroke and return are governed by devices which respond to the movement of the piston to a certain position. Devices of this type will shift the valve which controls admission of air to opposite ends of the cylinder mechanically upon movement of the piston a certain distance regardless of the time element involved. The timing of the stroke can, of course, be regulated to some extent by throttling the supply of air to the cylinder. Other known devices involve the use of motorized cams or direct mechanical connection between the valve and a machine being controlled.

My invention, as distinguished from these prior devices is controlled by pneumatic means supplied by air when the valve is in one or the other of its positions, preferably during the working stroke of the piston. It is thus not dependent on any mechanical connection with the piston or with the machine being controlled. Therefore, I am able to control not only the rate of travel of the piston by throttling its supply, but I am also able to vary the timing of the cycling of the piston independently. This is accomplished by additionally regulating the flow to the pneumatic control 'device, by adjustments in that device itself, or by a combination of the two. Thus, I can provide for very rapid cycling, even reversing the piston before it travels all the way to the end of the cylinder, or I can provide for any desired dwell time at the completion of the working stroke of the piston.

Other objects and advantages of the invention will hereinafter more fully appear.

In the accompanying drawings, I have shown for purpose of illustration, one embodiment which the invention may assume in practice. In these drawings:

FIG. 1 is a diagrammatic view of my improved cycling apparatus with the various parts in their positions during the working stroke;

FIG. 2 is a similar view but showing the parts in their positions during the return stroke; and

FIG. 3 is a section on line 33 of FIG. 1.

The cycling apparatus is shown as connected to a cylinder 6 containing a piston 7 with an operating rod 8 extending through one end of the cylinder. For controlling the admission and exhaust of air from opposite ends of the cylinder, there is provided a valve casing 9 connected at 10 to a source of air under pressure and having exhaust ports 11 and 12 on opposite sides of the inlet connection. Air is supplied to and exhausted from that end of the cylinder opposite the operating rod 8 through a suitable connection 13, and another connection 14 leads from the valve casing to the opposite end of the cylinder for controlling admission of air to that end for the return stroke and for exhausting air on the working stroke.

The valve 15 may be of the cylindrical type operating in a cylinder bore 16 of the valve casing 9. It has the space 17 in constant communication with the supply line 10 and from this space leads the passage 18 which supplies air under pressure to the connection 13 in the position of FIG. 1. The passage 19 supplies air under pressure 3,358,563 Patented Dec. 19, 1967 to the connection 14 when the parts are in the position shown in FIG. 2.

In the FIG. 1 position, an exhaust passage 20 in the valve establishes communication between the connection 14 and the exhaust port 11 while in FIG. 2, a similar passage 21 opens the connection 13 to the exhaust port 12.

The

needle valves

22 and 23 are provided at convenient places in the valve casing to throttle the flow of air to and from opposite ends of the cylinder. The valve is shifted to and held in the FIG. 1 position by a solenoid 24 and to the reverse position by a solenoid 25 after deenergization of the solenoid 24. The solenoids are activated for shifting the valves at the desired times by means of a pneumatically controlled device supplied with air under pressure when the valve is in its working stroke position through a connecting line 26. In this line, there is an adjustable regulating valve 27 effective to throttle the air flowing from the valve to a reservoir or compartment 29 and if desired, there may also be employed a one- Way pressure reducing valve 28.

The line 26 leads to the reservoir 29 which may house a suitable form of pressure responsive element. For this purpose, I prefer to use a body 30 consisting of foam material made from rubber or plastic and having closed cells. This body can be either a single hollow cylindrical piece or a plurality of doughnut-shaped pieces cemented together. It is anchored to the end wall 31 of the reservoir 29 by adhesive and its other end to a movable plate 32. An operating rod 33 extends through a suitable packing 34 extending through a hole in the frame 35.

The cylindrical reservoir 29 can be threaded into a boss 36 of the frame member 35. The rod 33 which is moved outwardly on increase in pressure in the reservoir 29 carries a switch operating cam 37 and the free end of the rod is supported in a boss 39. A spring 40 may be placed between the boss and cam 37 to assist in the return movement of the rod 33.

Solenoid 24 is energized from power line L, through

wires

41 and 42, normally closed switch 43 and wire 44 back to L During the working stroke as seen in FIG. 1, the foam material body 30 will decrease in length at a rate dependent on the adjustment of the

valves

22 and 27, and upon lapse of the desired time, the cam 37 will move to the right enough to lift the switch operating arm 45 to open switch 43 and de-energize solenoid 24. Upon a slight further predetermined movement, the cam 37 will push the switch operating arm 46 downwardly to close switch 47. This will energize the solenoid 25 from L through

wires

48 and 49, switch 47 and wire 50 so as to cause the valve 15 to shift to the FIG. 2. position which, of course, will effect the return stroke of the piston 7. At the same time, the air in reservoir 29 will flow freely through the line 26 to the exhaust port 12 and allow the switch operating cam 37 to return quickly to a starting position. As soon as the cam 37 moves far enough to open switch 47, solenoid 25 will be de-energized and shortly thereafter on the return movement of the switch operating rod 33, the arm 45 will drop and allow switch 43 to close so as again to energize solenoid 25 to complete the cycle.

The switches and their operating arms are carried on a block 51 slidably mounted on rods 52 in the frame 35 and a long threaded rod 53 can be manipulated by a knob 54 to adjust the switch-carrying block 51 relative to the cam 37. The

switches

43 and 47 together with their operating arms, are adjustable relative to the cam 37 and relative to each other. For this purpose, each switch and its operating arm are fixed to a plate 55 having

slots

56 and 57 at opposite ends. By loosening the hold-down screws 58, these plates can be adjusted to the exact position desired. The block 51 also carries the boss 39 previously mentioned.

By the adjustments provided for the switches, the time required for their operation is changed because the length of the operating rod movement depends on the pressure build-up in the compartment or reservoir 29. For example, the switches can be adjusted so that they will operate after only a slight movement of the pressure responsive element; or if the time interval desired for the piston cycle is greater, then the switches can be adjusted to require maximum build-up, of pressure in the reservoir 29.

The speed of the piston stroke is controlled by the

needle valves

22 and 23 which will also regulate to some extent, the rate of the return stroke. Besides the throttling accomplished by valve 22, the regulating valve 27 can also be adjusted to vary the time required for the pressure build-up in reservoir .29. A very small bleed opening 59 is for the purpose of preventing build-up of heat in the reservoir, which might result from the continuous flexing of the foam material body 30.

, It will accordingly be seen that I have utilized a pressure responsive switch actuating means governed by the air pressure between the valve and the cylinder during the operating stroke which is capable of regulation over a very wide range to provide the desired time cycle of the piston independent of mechanical devices actuated by the piston itself. Such a device is capable of being set up at a remote station rather than being stationed directly to the machine to be controlled.

What I claim is:

In combination with an air cylinder, a piston in the cylinder having an operating rod extending through one end of the cylinder;

(a) a valve casing having separate connections to opposite ends of said cylinder;

(b) a valve in said casing movable between a first position which admits air to one end of the cylinder while opening the other end to exhaust, and a second position to admit air to said other end while exhausting the first end of said cylinder;

(c) means for shifting said valve from the first position to the second position;

(d) a pneumatically controlled device supplied by air from said valve in said first position for activating said shifting means;

(e) additional means for regulating the flow of air to said pneumatically controlled device, said pneunatically controlled device comprising a compartment in communication with said valve, a pressure responsive element in said compartment, a switch actuator connected to said element, a switch actuated thereby A and a solenoid connected to said valve and Whose energizing circuit is controlled by said switch; A

(f) means for manually adjusting the position of said switch relative to said actuator to vary the time of cycling by said valve;

(g) a second solenoid connected to the valve for returning it from its second position to its first position, and a second switch controlled by said switch actuator, said second switch being in the energizing circuit of said second solenoid; and

(h) means for manually adjusting the position of one of said switches relative to the other.

References Cited UNITED STATES PATENTS 2,302,232 11/1942 MacNeil 91--3 18 2,691,962 10/1954 Johnson 91-275 2,698,517 1/1955 Witt 91-318 3,045,704 7/1962 Williams 92-90 3,168,012 2/1965 Wililams 9290 FOREIGN PATENTS 599,876 6/ 1960 Canada.

MARTIN P. SCHWADRON, Primary Examiner.

PAUL E. MASLOUSKY, Examiner.