US2422495A - Electric piston - Google Patents

Description

June 17, 1947.

c. H. MQRROW ELECTRIC PIsToN Filed Aug. 18, 1943 2 Sheets-Sheei l BY /l/f am# ATTORNEYS.

.june 79 i943?. C, H MORROW 2,422,495

ELECTRIC PISTON Filed Aug. 18, 1943 2 Sheets-Sheet 2 ze 39a INVENToR. CL 4mm/cf fo/aww Hf@ Mf/ Patented June 17, 1947 ELECTRIC PISTON Clarence H. Morrow, Shaker Heights, Ohio, as` signor to The Hotstream Heater Company, Cleveland, Ohio, a corporation of Ohio Application August 18, 1943, Serial No. 499,093

(Cl. i4-424.8)

11 Claims. l

This invention relates to what for convenience may be called an electric piston, to-wit, a motor operated plunger capable of use for actuating many different devices, such as Valves, shutters or dampers in Ventilating, heating, air conditionlng and combustion equipment.

One object of the invention is to provide an improved electric piston which may be assembled on the bench and sold in unit form, and which includes within a casing or housing all necessary operating parts, such as an electric motor, a reciprocating plunger, a coupling between the motor and said plunger, limit switches for controlling the plunger stroke, switch actuating means, etc.

A further object is to improve the arrangement and mounting of the parts, so las to produce smooth quiet operation and reduce wear.

Still another object is to so simplify and mount the parts as to avoid bad effects of misalinement and reduce costs for manufacture and assembly.

Another object of the invention is to provide a simple :and readily adjustable actuating member for the outer one of the two limit switches, to thereby enable the length of the piston stroke to be reduced or shortened as desired, said actuating member being capable of convenient application to the plunger when its use is desired, and removal therefrom when its use is no longer desired.

Another object of theinvention is to reduce the weight and cost of metal parts and the numlber and kind of machine operations, enabling the pistons'to be made and assembled by quantity production methods, with consequent reliability and uniformity.

Further objects of the invention in part are obvious and in part will appear more in detail hereinafter.

In the drawings, which represent one suitable embodiment of the invention, Fig. 1 isa sectional elevation on the line |-I, Fig. 2, looking in the direction of the arrows;

Fig. 2 is a sectional elevation on the line 2--2, Fig. 1;

Fig. 3 is a detail cross sectional view on the line 3.-.3, Fig. 1, and showing the adju-stable actuating member for the outer one of the two limit switches;

Fig. 4 isl an enlarged detail view, showing the drive coupling; and

Fig. 5 is a, sectional plan view, somewhat enlarged, on the line 5-5, Fig. 4.

The drawings, for convenience and in no sense of limitation, illustrate a single form of the 111-.

vention, although variations and modifications are contemplated, within the scope of the claims appended hereto.

The piston Vas here illustrated includes a suitable housing or casing made of two parts, to-wit, a Ibase I0 having a rim or wall II and a cover I2, the base and cover being secured together around their peripheries, as by bolts or screws I3. The base is suitably formed for attachment to a support, its flat oor I 4 being shown a-s provided with perforated ears I5, I6 through the openings in which screws may be'passed into a wall or other support. In the rim o-r Wall I I of the base, an opening Il is provided through which lead wires for the electric circuit may be passed. The cover I2 fits the rim or wall Il of the base along the parting plane I8, and the two members I0, I2 together define a closed chamber I9 in which the operating mechanism is located. Either or both of the casing members may be provided with Ventilating openings for -carrying away the heat of the motor and that generated in friction, such openings Ibeing shown, for example, ai', 2i), 2|,in the base I0.

The roperating mechanism includes a suitable y reversible electric motor 22 having operatively connected thereto, by suitable reduction gearing (not shown), a drive shaft 24, said gearing and said drive shaft being mounted in a casing or housing 23. By the means and in the manner hereinafter described, the motor driven shaft 24 is operatively connected by a coupling 25 to a screw threaded shaft 26 provided with an internally threaded Vhead 21 for movement therealong. To said head is threaded or otherwise suitably connected a tubular plunger 28 extending through a guiding opening in the base I0 to the outside, where it is provided with an operating ear 29 having an opening Sil, the connection of said plunger to the head 21 being here maintained by a lock nut Zia. Thefaforesaid parts (with the exception of the outwardly projecting free end of the plunger 28) all lie within the easing or housing cham-ber I9, and thus are readily accessible for purposes of inspection, repair or replacement, the removal of the cover I2 being accomplished without disturbing such parts.

Screwed or otherwise suitably firmly secured within the casing or housing chamber I9 is a rigid brackets! having an opening for the mounting of the hereinafter described coupling 25. As here shown, the bracket wall surrounding rsaid open-` ing is enlarged at each end of said opening to provide a pair of spaced recesses with a wall portion 32 therebetween. Located within said recesses are standard thrust bearings, the bearing 33 seating against one face of the intermediate wall portion 32 and the bearing 34 seating against the other face thereof, said faces being flat and parallel for the accurate positioning of said bearings. Engaging the bearing 34 is the shoulder 35a of the headed end 35 of the coupling member 25a, said shoulder being normal to the longitudinal axis of said coupling member, as flat as possible and in parallel relation with the faces of thev Engaging intermediate bracket wall portion 32. the bearing 33 is the flat face of a collar 36 Vwhich surrounds the other and recessed `end of the coupling member 25a. In order that said collar face may be located in generally parallel relation with the faces of the bracket intermediate wall portion 32 and with the shoulder 35a of the headed end 35 of the coupling member 25a, and thus properly engage the bearing 33, the collar 36 is pinned to the recessed end of said coupling member. Preferably, the bracket and coupling parts are held in a suitable jig or the like while the position of the collar is being determined, and while so held, the holes for the pins 36a are produced and the pins driven into such holes, thereby insuring a proper kmounting of the coupling in the bracket opening, with the coupling member 25a freely rotatable about its longitudinal axis.

VFor the mounting of the motor 22 and the casing 23 for the reduction gearing and the drive shaft 24, a supporting plate 31 is screwed or otherwise suitably secured to the bracket 3l, the ymotor 22 being secured to said plate on one side thereof and the casing 23 being secured to said plate on the other side thereof, all as clearly shown in the accompanying drawings.

As will now appear, the drive shaft 24 and the threaded shaft 26 are operatively connected to the coupling' member 25a in such manner as to avoid any objectionable effects of possible misalinement, due to inaccuracies of workmanship or beyond the tolerances permitted by the quantity production methods employed in manufacf ture of the piston. As shown, these connections are of simple androf more or less crude universal joint form. For example, at its power receiving end, the coupling member 25a is socketed or recessed at 38 to receive an end portion of the drive shaft 24 said shaft being provided with a Vcross pin 39 having its ends extending into slots 39a in the socketed recessed end of the coupling .memben As shown, the shaft 24 is slightly smaller than the socket or recess 38, so that the drive effect is transmitted, without loss, even thoughthe ,axis of shaft 2Q is slightly offset or askewY with relation to the axis of the coupling member 25a.

Likewise, the opposite headed end 35 of the coupling member 25a is provided with a socket or recess 36 to receive the slightly smaller end portion 26a of the threaded screw shaft 26, a driving connection between such parts being effected by a cross pin lll, as will be readily understood.

The tubular plunger 26 is guided, during its endwise motion, by the walls of the casing base opening 132 in which said plunger slides,. and

also'by a rigidV rod 43 passing through an openingr 24 inY the casing base and screwed into or otherwise secured Yin an opening in the bracket 3|, as at d5, said rod( also passing through' an opening in an ear 46 onV one side of the threaded head 2,1. Thus, the rodVr 43 not'only serves vto guideY and support the inner end of the plunger but also, to prevent itsv rotation, thus I areservihgY the position of the perforated ear 29 at the free or outer end of the plunger which serves as the connection thereof to the device which the plunger is intended to operate.

The plunger 28 serves to support and guide the free or outer end of the threaded shaft 26, the external diameter of which is smaller than the internal diameter of the plunger.` As here shown, the shaft 26 is provided on its free or outer end with a ball-shaped ring `il closely fitting the internal surface of the plunger, and preserving alinement between the plunger and the threaded shaft 26. A similar ball-shaped ring, such as the one designated by the reference numeral t3A in Fig. 5, may be used, if desired, at the joint between the drive shaft 23 and the coupling member 25a. s

ToA lubricate the parts, the bracket 3l is here provided with a lubricant passageway leading to the relatively rotatable surfaces at and adjacent the coupling, the outer end of saidV passageway being provided with a suitable fitting 5l)v for the connection thereto of a lubricating device.` A similar lubricant passagewaymay be, and here is, provided in the head 21 which travels along the threaded shaft 26 and to which the plungerr 28 is connected, said passageway leading to the cavity 5I at the inner end of the shaft 26 `and being provided at its outer end with a fitting 52 corresponding to the tting 50. Likewise, the packing 53 at the plunger-guiding4 opening in the casing base Il) may be lubricated through a channel normally closed by a removable cap 54, as shown in Fig. 1.

In the casing or housing chamber I9 are mounted two limit switches 55 and 56, the operating parts of which are actuated by spring arms 51, each provided with a roller ESL Although the roller 58 ofeach switch may be depressed, for

Switch actuation, by a lug 59 on the head 21 which travels along the screw shaft 26, only the inner limit switch 55 is here actuated by such lug. In the present embodiment of the invention, a separate member 60 is provided (see Figs. 1, 2 and 3) for the depression of the roller 58 of .the outer limit switch 56, said nember having the position ofthe member 6l) on said plungerv can be varied to shorten the plunger stroke asY desired. A lug 6| on the body portion of member 60 coacts with the roller 58 of the switch 56 to effect switch actuation, and a pair of armsV 62 on said bodyportionV straddle the guide'rrod 43 and thus prevent rotary movement of this switch actuating member 66 relative to the 'stopping operation of themotor 22, by actuation of such switch, awaiting motor reversal bymanual control, or as here, effecting automaticreversal of said motor.

roller 58 of the inner limit switch 55, as will be readily understood. l Y i Inward movement ofthe plunger 28is controlled,of course, by/the'en7. gagement of the lugY 59" of .the head 21 with thev The construction described is of simple form capable of manufacture and sale at relatively low cost,rand is durable and sturdy in service. It is capable of assembly on the bench and most of its parts are either of more or less standard form, capable of purchase in-the open market, or lend themselves to quantity production at low cost. The device is smooth and quiet in operation, unnecessary friction and wear being eliminated, and is certain in operation. When in use, all parts are conveniently accessible for repair or replacement. Moreover, the drive shaft 24 and the screw shaft 26 are so coupled that misalignment thereof due to quantity production methods and the like, is of no consequence.

To those skilled in the art, other advantages of pistons embodying the invention will be apparent from the foregoing description of one such embodiment.

What I claim is:

1. A device of the character described, comprising a chambered casing having a support rigidly mounted therein, a coupling member mounted in an opening of said support to rotate on a fixed axis, motor means mounted in the casing at one end of the coupling member and including a driving shaft generally coaxial with the coupling axis, a threaded shaft on the other end of the coupling member `and also generally alined with its axis, operating connections between the coupling member and said two shafts, and a tubular plunger extending to the outside of the casing and operated by said threaded shaft.

2. A device ofthe character described, comprising a chambered casing having a support rigidly mounted therein, a coupling member mounted in an opening of said support to rotate on a fixed axis, motor means mounted in the casing at one end of the coupling member and including Va driving shaft generally coaxial with the coupling axis, a threaded shaft on the other end of the coupling member and also generally alined with its axis, self-accommodating universal joint connections between said coupling member and each o-f said two shafts, and an op erating plunger actuated by said threaded shaft.

3. A device of the character described, comprising a chambered casing having a support rigidly mounted therein, a coupling member mounted in an opening of said support to rotate r on a fixed axis, motor means mounted in the casing at one end of the coupling member and including a driving shaft generally coaxial with the coupling axis, a threaded shaft on the other end of the coupling mem-ber and also generally alined with its axis, operating connections between the coupling member and said two shafts, and a tubular plunger enclosing the threaded shaft and at its inner end having a nut traveling on the threads thereof, the outer end of the plunger extending to the outside of the casing.

4. A device of the character described, comprising a, chambered casing having a, support rigidly mounted therein, a coupling member mounted in an opening of said sup-port to rotate on a xed axis, motor means mounted in the casing at one end of the coupling member and including a driving shaft generally coaxial with the coupling axis, a threaded shaft on the other end of' the coupling member and also generally alined with its axis, operating connections between the coupling member and said two shafts, a tubular plunger enclosing the threaded shaft and at its inner end having a nut traveling on the threads thereof, the outer end of the plunger extending to the outside of the casing, andL guiding means between the outer end of the plunger and both the casing and threaded shaft.

5. A device of the character described, comprising a chambered casing having a support rigidly mounted therein, a coupling member mounted in an opening of said support to rotate on a xed axis, motor` means mounted in the casing at one end of the coupling member and including a driving shaft generally coaxial with the coupling axis, a threaded shaft on the other end of the coupling member and also generally alined with its axis, operating connections between the coupling member and said two shafts, a tubular plunger enclosing the threaded shaft and at its inner end having a nut traveling on the threads thereof, the outer end of the plunger extending to the outside of the casing, and means connected to the aforesaid support for preventing plunger rotation.

6. A device of the character described, comprising a chambered casing having a support rigidly mounted `therein and provided with an opening surrounded by a wall portion, a coupling member rotatable on a fixed axis in said opening and provided with end thrust bearing means engaging opposite faces of said wall portion, a driving motor mounted in said casing on one side of said support, a threaded shaft on the other side of said support, a plunger operated by said threaded shaft, and universal joint connecting means between said coupling member and each of said motor and threaded shafts.

7. A device of the character described, comprising a chambered casing having an apertured support rigidly mounted therein, a coupling member mounted in said aperture for rotation about its longitudinal axis, said coupling member having a shouldered portion on one side of Said aperture to prevent endwise movement of said coupling member in one direction, a collar pinned to said coupling member on the other side of said aperture to prevent endwise movement of said coupling member in the opposite direction, axially disposed recesses in said coupling member on opposite sides o-f said aperture, a motor -driven shaft extending into one of said recesses and operatively connected to said coupling member, a screw threaded shaft extending into the other of said recesses and operatively connected to said coupling member, and a plunger connected to said threaded shaft and projecting outside said casing for reciprocatory movement.

8. A device of the character described, comprising a chambered casing having an apertured support rigidly mounted therein, a couplingl member mounted in said aperture for rotation about its longitudinal axis, said coupling member having a shouldered portion on one side of said aperture to prevent endwise movement of said coupling member in one direction, an end thrust bearing between said shouldered portion and said support, a collar pinned to said coupling member on the other side of said aperture to prevent endwise movement of said coupling member in the opposite direction, an end thrust bearing between said collar and said support, axially disposed recesses in said coupling member on opposite sides of said aperture,A a motor driven shaft extending into one of said recesses and operatively connected to said coupling member, a screw threaded shaft extending into the other of said recesses and operatively connected to said coupling member, and a plunger connected to said threaded shaft and projecting outside said casing for reciprocatory movement.

9. A device of the character des'cribed, comprising a chambered casing having a support rigidly mounted therein, said support being provided With'an apertured Wall portion and having recesses surrounding said aperture on opposite sides of said Wall portion, a coupling member mounted in said aperture for rotation about its longitudinal axis, end thrust bearings mounted in said recesses, said coupling member having a .shouldered portion on one side of said aperture and engaging one of said bearings to prevent endvviseV movement of said coupling member in one direction, a collar pinned to said coupling member on the other side of said aperture and engaging the other bearing to prevent endwise movement of said coupling member in the opposite direction, axially disposed recesses in said coupling member on opposite sides of said aperture, a motor driven shaft extending into one of said recesses, a screw threaded shaft extending into the other of said recesses, said shafts being generally co-axial with said coupling member, self-adjusting connections between said shafts and said coupling member, and a plunger connected to said threaded shaft and projecting outside said casing for reciprocatory movement'.

10. A device of the character described, comprising a chambered casing having a support de- Vtachably mounted therein, said support being provided with an apertured wall portion and'having recesses surrounding said aperture on opposite sides of said Wall portion, a coupling member mounted in said aperture for rotation about'its longitudinal axis, end thrust bearings mounted in said recesses, said coupling member having a shouldered portion on one side of said aperture and engaging one of said bearings to prevent endwise movement of said coupling member in one direction, a collar pinned to said coupling member on the other side of said aperture and engaging the other bearing to prevent endwise movement of said coupling member in the opposite direction, axially disposed recesses in said lNumber coupling member Von opposite sides of said aperture, a motor driven shaft extending into one of said recesses, a screw threaded shaft extending into the other of said recesses, said shafts being generally co-axial With said coupling member, self-adjusting connections between said shafts and said coupling member, and a plunger connected to said threaded shaft and projecting outside said casing for reciprocatory movement.

11. A device of the character described, come prising a chambered casing having an apertured bracket detachably mounted therein, a coupling member mounted in said aperture for rotation about a fixed axis, a supporting plate carried by said bracket, motormeans carried by said plate on one side thereof, a housing carried by said plate on the other side thereof and supporting a drive shaft and reduction gearing operatively connecting said shaft and saidmotor means, means operatively connecting said drive shaft and said coupling member, a threaded shaft operatively connected with said coupling member, said drive shaft and said threaded shaft lying on oppositesides of said support and generally coaxial With said coupling member, and a plunger connected to said threaded shaft for reciprocation thereby and extending to the outside of said casing.

CLARENCE I-I. MORROW.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Name Date Stapelfeldt July 28, 1942 Konig Jan. 5, 1943 Santen July 1, 1941 Gill Sept. 7, 1943 Strong May 11, 1943 Simpson Feb. 23, 1943

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