US2297025A - Air pump - Google Patents

Description

Sept. 29, 1942- G. w. RUSSELL AIR PUMP Filed July 14, 1941 4 6 52 a .5 5, MW H a 1M 1 H m Z 57 Z 7 z 0 .0 a 59 x 4 wwww yea/ya 14/ Randell,

INVENTOR.

ATTO NEY.

Patented Sept. 29, 1942 UNETED STATES PATENT- OFFICE AIR PUMP George W. Russell, Denver, Colo.

Application July 14, 1941, Serial No. 402,295

2 Claims.

This invention relates to improvements in air pumps.

For certain purposes it is necessary to provide a source of air under pressure, as, for example, where beer is dispensed it is necessary to keep the containers supplied with air to prevent the carbon dioxide from escaping and to cause the liquid to flow; dentists and physicians require a supply of compressed air to be constantly available, service stations must maintain a supply of compressed air for tire inflation, etc.

It is the object of this invention to produce an electrically operated pump that can be employed for providing compressed air for any of the above purposes as well as for any other purpose where the quantity is not too great.

Another object is to produce a pump that shall be of extremely simple construction and which can therefore be manufactured and sold at a moderate price.

A still further object is to provide a pump of such construction that its capacity can be readily adjusted and which can also be adjusted to vary the pressure of gas delivered.

The above and other objects that may become i apparent as this description proceeds are attained by means of a construction and an arrangement of parts that will now be described in detail and for this purpose reference will be had to the accompanying drawing on which the invention has been illustrated and in which:

Figure 1 is a vertical section through a pump constructed in accordance with this invention;

Figure 2 is a fragmentary section similar to that shown in Figure 1 and shows a diaphragm pump substituted for the plunger pump shown in Figure 1;

Figure 3 is a vertical section showing a slightly modified form of construction;

Figure 4 is a section taken on line l4, Figure 3, and shows a switch for opening and closing the energizing circuit for the electromagnet; and

Figure 5 is a view .partly in section and partly in elevation showing a slightly modified form of construction.

In the drawing reference numeral l designates a base which may be secured to a stationary support which has been indicated by reference numeral II in Figure 1. Attached to the upper surface of the base is a solenoid |2 comprising an I inner tubular member |3 of nonmagnetic material and an outer covering M of soft iron. At the bottom of the opening in the tubular member 3 a rubber cushion I may be located, if desired. A core I6 is attached to the lower end of a bar I! that passes through an opening H3 in the top I9 of a housing or supporting member whose side has been designated by reference numeral 20. A tubular housing 2| is secured at its lower end to the top I9 and is provided with a cap 22 through which the rod |1 extends. A collar 23 is attached to the rod near the top of the tubular member 2| and serves as an abutment for the upper end of spring 24 whose lower end rests on the upper surface of the top ill. The spring is under compressive strains and tends to move the rod I! upwardly. A collar 25 is secured to the rod I! below the top I9 and this collar is so positioned that the spring will urge it into engagement with a rubber cushion or rebound member 26 that is secured to the under side of the top I9 by means of a clamping member 21. The collar 25 is so positioned that when the rod I! is in its uppermost position, the lower end of the core IE will extend into the central opening in the solenoid. An arm 28 is attached to the rod directly above the solenoid, and serves as a switch operating member in the manner which will be presently described. One end of the solenoid is connected 'by means of a conductor 29 with a source of electrical energy which has been indicated as a battery, but which may be the ordinary service wires of any building. The other end of the solenoid winding is connected to a switch contact 30. A switch arm 3| is pivoted at 32 and can be moved on to the contact 3| or ofi from it as may be desired. A conductor 33 connects the switch arm 3| with one terminal of a mercury switch 34. Extending from the other terminal of this switch is a conductor that connects with the opposite side of the battery. When switch 34 is in the position shown in Figure 1, mercury therein establishes electrical contact between the conductors 33 and 35 and if switch arm 3| is in the position shown in Figure 1, current will flow through the solenoid, which thereupon attracts the core l3 causing the latter to move downwardly and compress the spring When the core has reached its lowermost position, switch 3| is opened .by a mechanism which will now be described. Secured to the wall 20 is a guide member 36 that is provided with two arms 31 and 38. A rod 39 is slidably mounted in two vertically aligned openings in members 31 and 38 and the ends of this rod are reversely bent so as to form a downwardly extending member 4-0 that projects through an opening in the arm 37 and an upwardly extending member 4| that projects through an opening in the arm 38. The switch connector 28 is positioned between the ends of parts 40 and 4| and .63 surrounded by a flange 34.

, when the core moves downwardly from the position shown in Figure 1, due to the tractive efiort of the solenoid, the latter :will be energized until arm 28 engages the upper end of 4| and moves it downwardly until the switch comprising the switch arm 3| is open. As soon as the circuit is open, spring 24 moves the rod I! and :core I6 upwardly until the collar 25 engages the rebound member 26. Just before the upper limit of the stroke is reached, arm 28 engages the end 40 and moves member 39 upwardly, thereby closing the switch 3|, whereupon the solenoid is reenergized and pulls the core 16 downwardly. This reciprocation of the core continues as long as current is supplied.

In the present embodiment, the reciprocating motion of rod I1 is employed to operate an air pump. This pump has a cylinder 42' that is supported on the upper end 43 of a bracket whose vertical arms have been designated by reference numeral 44. The lower end of the cylinder has been shown as provided with a flange 45 that has openings for the reception of bolts E8 by means of which it is attached to the top 45, The upper end of'rod I? is provided with a piston All that has an airtight fit with the under cylinder wall. A

cylinder head 48 is removably attached to the upper end of the cylinder by means of bolts 39. This cylinder head is provided with an inlet port and an outlet port 5!. These ports are provided with check valves 52 that permit air to flow from the inlet to the outlet, but not in the opposite direction. When the piston M is reciprocated by the means above described, it will suck air into the pump cylinder through the inlet and discharge it through the outlet opening. A pipe 53 'extends from the outlet to any suitable reservoir 54. If it is desired to make the mechanism automatic so as to maintain a constant pressure in the reservoir 54, this is atained by providing a pressure operated means foropening and closing the mercury switch 34. In the drawing the pressure responsive switch operating means has been shown in a diagrammatic manner and comprises a stationary support 55 to which a cylinder 55 is attached. A piston 51' is mounted for reciprocation in the cylinder and is connected by means of a piston rod 58 with an arm 59 to the mercury opening 50 and an outlet opening 5! controlled by check valves 52, the same as in Figure 1. A plate 66 is attached to the top 45 by means of screws or bolts 45 and this, in turn, supports brackets 51 by means of which the head 63 is attached to the plate 65. When the rod I1 is reciprocated by the means above described, the diaphragm will be flexed and will cause air to enter the chamber in the pump and to be expelled therefrom in a manner well understood. The diaphragm pump shown in Figure 2 is better suited for the purpose than the plunger pump shown in Figure 1 where larger quantities of air are to be compressed at moderate pressures.

It is sometimes desirable to be able to adjust the pump so as to reduce its stroke in comparison with the distance through which the bar I! reciprocates, so as to obtain a greater discharge switch mount which is pivoted at 68. A tension 7 spring 5| serves to hold the mercury switch in closed position. The interior of cylinder 55 is connected with the pressure pipe 53 by means of a tube 6|. The tension of tube 60 is so adjusted with respect to the diameter of the piston 5'! that when the pressure in the pipe 53 reaches a predetermined value, the mercury switch will open, thereby disconnecting the solenoid from the source of power. As soon as the pressure decreases below the predetermined value,'the parts will be moved to switch closing position, whereupon the reciprocating electric motor will begin to function and to pump air into the cylinder 54 until the desired pressure is again attained.

In Figure 1, the pump has been shown as an ordinary plunger pump and this is very well suited where high pressures and moderate capacisurface of flange '54, The head 62 has/an'inl'e't pressure with the same attractive forces of the magnet.

In "Figure 3 a modification has been shown in which the spring 24 has been dispensed with and the tubular guide member 2i has been replaced by a bearing 61 through which the bar 1-! passes. The upper end of bar I? is connected by means of a pivot pin 53 with one end of the flexible cantilever spring 39, the other end of this spring is clamped between the outwardly extending edges 10 and H of the bracket 12 and the top 13. A diaphragm pump like that shown in Figure 2 and above described is attached to the upper surface of member I3 and spaced from the latter by means of spacers 67a. A connecting rod Ha is attached to the under surface of the diaphragm .65 and has its lower end pivoted at 14 to a clamping member '55 that can be longitudinally adjusted along thespring 69 and held in adjusted position by means of a set screw '16. By moving the pump and the clamping member 15 towards and away from the pivot 61, the length of stroke can be adjusted so as to obtain the optimum .oper

ation for the work to be done.

In Figure 3, a slightly different switch has been shown for opening and closing the circuit to the solenoid. This switch consists of an arm I! that is pivoted at 18 and is provided'at one end with opposed stop -members -19 and -80. The

stop members are spaced apart and so positioned that they can be-engaged by the arm (28 during the operation of the motor. The battery is connected to one end of the solenoid by means of a wire 29 and has its other end connected with switch terminal 3i! by means of a conductor 8|. Arm II has a projection 82 that in one position bridges the gap betweenconductors 39 and 83 as shown in Figure 4. When arm82 is in the position shown in Figure 4, current will flow to the solenoid provided the mercury switch 34 is closed. When the core I6 is moved downwardly by the attraction of the solenoid, arm 28 will engage the stop '89 and move the switch contact 82 upwardly onto the contact 83 until the electrical connection between the two contacts 3B and 83 is broken. To prevent excessive sparking, contacts 36 and 83 are bridged by a condenser 84.

In Figure 5 a slightly modified form of construction has been shown. .In this embodiment the diaphragm pump 63 is shown as attached to the upper surface of member l3 and connected with the rod 11 by means of a rocker arm -85. This rocker arm has adjustably secured thereto a clamp 86 that carries a pivot 81. The pivot is journaled in a bearing member .88 that is adjustably attached to a'horizcntal bar .69. The pivotal connection between the rocker arm and rod [1 has been designated by reference numeral 90 and. the other end of the rocker arm has a rod 9| pivotally connected therewith at 92. The rod 9| is slidably connected with a tube 93 that, in turn, is connected with the diaphragm by a pivot 94. A set screw or equivalent device 95 serves to hold the members 9| and 93 against longitudinal movement. It is evident that by shifting the fulcrum 81 the leverage between the pump and the rod I! can be adjusted so as to decrease the stroke and increase the pull or vice versa.

It is to be understood that the mechanism shown in Figure is diagrammatic only and that it may be changed in its specific details so long as it accomplishes the function of changing the ratio of the lever by adjusting the position of the fulcrum.

It is evident from the above description that the mechanism illustrated on the drawing and described herein is very simple and that it can therefore be manufactured and sold at a comparatively small cost.

Attention is called to the fact that the solenoid merely compresses the spring 24 and moves the piston 41 downwardly during the intake stroke of the pump and that the exhaust stroke of the pump is effected by means of the spring 24. In the embodiment illustrated, the pumps are single acting. The length of the pump stroke is determined by the distance between the stops 4!] and 4| and means may be provided for adjusting this distance if desired. It is also evident that the length of the pump stroke can be varied by changing the transverse dimension of the arm 28 as well as by changing the distance between the stops.

Having described the invention what is claimed as new is:

1. An electrically operated pump comprising a base, a solenoid supported thereon, a member positioned above the solenoid, said member having a guide opening in axial alignment with the solenoid, a rod slidably mounted in the guide opening, a core on the lower end of the rod for movement into and out of the solenoid, a switch in series with the solenoid winding, means comprising a switch arm and a cooperating arm engaging member operatively connected with the core for opening the switch when the core is in attracted position within the solenoid and for closing it when the core is withdrawn from the solenoid, a cantilever spring having one end clamped to the base and the other end pivotally connected with the upper end of the rod, the spring being biased to normally move the core upwardly and out of the solenoid, a pump support carried by the base and positioned above the spring, the pump having a stationary and a movable element, the stationary element being adjustably attached to the support, a connecting rod having its upper end attached to the movable pump element, and means for attaching the lower end of the connecting rod to the cantilever spring, said means being adjustable along the spring for varying the capacity of the pump per stroke.

2. An electrically operated pump comprising a base, an electromagnet supported thereon, a member positioned above the electromagnet, said member having a guide opening in alignment with the electromagnet, a rod slidably mounted in the opening, an armature on the lower end of the rod for movement towards and away from the electromagnet, a switch in series with the electromagnet winding, means comprising a mechanism operated by the movement of the armature for opening the switch after the armature has moved to a predetermined position in response to the attraction of the electromagnet, and for closing it when the armature has moved a predetermined distance away from the electromagnet, a cantilever spring lever having one end clamped to the base and the other connected with the rod, the spring being biased to normally move the rod and armature away from the electromagnet, a pump support carried by the base, the pump having a stationary and a movable element, the stationary element being adjustably attached to the support, a connecting rod having one end attached to the movable pump element and its other end adjustably connected with the spring for movement therealong for varying the capacity of the pump per stroke.

GEORGE W. RUSSELL.

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