US2938347A

US2938347A - Power source for hydraulically operated devices

Info

Publication number: US2938347A
Application number: US693347A
Authority: US
Inventors: Malcolm B Sturgis
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-10-30
Filing date: 1957-10-30
Publication date: 1960-05-31
Anticipated expiration: 1977-05-31

Description

May 31, 1960 M. B. STURGIS 2,938,347

POWER SOURCE FOR HYDRAULICALLY OPERATED DEVICES Filed 001:. 30, 1957 '4 Sheets-Sheet 1 FIG. I. ,7 /43 5 I49 4 Q 153 55 151 i 97 3 91 19 2/ I56 May 31, 1960 M. B. STURGIS POWER SOURCE FOR HYDRAULICALLY OPERATED DEVICES Filed Oct. 30, 1957 4 Sheets-Sheet 2 M. B. STURGIS May 31, 1950 POWER SOURCE FOR HYDRAULICALLY OPERATED DEVICES Filed Oct. 50, 1957 4 Sheets-Sheet 3 5 l 93 I 95 iol T fie] 19 5/97 awake/9,9

May 31, 1960 M. B. STURGIS POWER SOURCE FOR HYDRAULICALLY OPERATED DEVICES 4 Sheets-Sheet 4 Filed Oct. 30, 1957 United a P ent *C) rowan SOURCE FOR HYDRAULICALLY, OPERATED DEVICES Malcolm B. Sturgi s, Kirkwood, Mm, (601 S. Taylor St., St. Louis 10, Mo.)

Filed Oct. 30, 1957, Ser. No. 693,347

. 1 Claim. (Cl. 60-52) tools such as drills, rivet squeezers, broaching tools, bolt pullers and the like; the provision of a power source of the class"described which is convenient to bring into power-supply position with respect to the hydraulic devices to be served; the provision of hydraulic apparatus of the class described which for a given capacity is much lighter in weight and compact in form than prior electrically driven apparatus in the same general category and which heretofore has imposed considerable overloads on industrial'wiring; and .the provision of-apparatus of the class described which has low cost of maintenance by elimination of any constantly moving prime mover such as theformerly used pump-driving electric motors. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of which will be indicated in the following claim.

form of portable unit made according to the invention;

Fig. 2 is a longitudinal section taken on line 2-2. of Fig. l; Fig. 3 is a longitudinal section taken on line 3-3 of Fig. 1;

Fig. 4 is a transverse section taken on line 4-4 of 1' Figs. 1 and 2; i

Fig. 5 is a left end view'of Fig. 1, parts being broken away to expose certain interior parts;

Fig. 6 is an enlarged'longitudinal section, taken on line 6-6 of Fig. 1, illustrating a heat interchanger, parts being broken away; r g

N Fig. 7 is a cross section taken on line 7-7 of Fig. 6;

Fig. 8 is a combined pneumatic and hydraulic flow diagram between parts corresponding to parts shown in Figs. 1-7; A

Fig. 9 isan axial section, of an alternative form of heat interchanger;

Fig. 10 'is a cross section taken on line 10-10 of 9;and

Fig. 11 is a combined pneumatic and hydraulic flow diagram showing as alternative arrangement of parts including the heat interchanger illustrated in Figs 9 and 10. I Corresponding reference characters indicate .corre Fig.

Patented May. 31, 1960 type, such as hydraulic drills, rivet s'queezers, clamps,

broaching tools, bolt pullers and the like, which require a supply of hydraulic fiuid under substantial pressure, such as, for example, 2800 p.s.i. It is costly to pipe a factory, shop or the like to bring a supply of hydraulic fluid, particularly at such a pressure, to various'locations at which hydraulic tools are used. Consequently, it has heretofore been the practice to provide portable electric motor-driven hydraulic pumps adapted to be plugged into the usual electric wiring system. Such arrangements have not been entirely satisfactory because the electrical driving equipment required elaborate fan-cooling arrangements, imposed a considerable overload on most industrial wiring, and involved a high maintenance cost because of the constant motorizing action imposed upon the hydraulic pump systems. Such constant action could not be avoided by starting and stopping the driving motors according to fluid demand because of the complex switching and other arrangements required and because of the nonpositive lagging, starting and stopping actions.

' -The present invention takes account of the fact that for quick-detachable connection to such an air supply and to the tools, wherein the parts are called upon to move only when there is a demand by one or more tools for pressurized hydraulic fluid. Movement when required sets in promptly and positively at full pressure. Cool operation is brought about without the use of fans.

Referring now more particularly to the drawings, Figs. 1-7 showpractical physical shapes and arrangements of the parts of one 01m of the invention in order to form a portable unit 1. These parts are related as-diagrammatically shown in Fig. 8. Numeral 3 indicates a light-weight supply tank for a small amount of hydraulic fluid (several gallons, for example), such as oil or the like, having an adjustable low-pressure relief valve 4 set to operate, say, at 5 p.s.i. This tank has a hydraulic outlet or supply line 5 passing through a cooling coil 7 of a heat interchanger 9 (indicated by the dash lines in Fig. 8). The line 5 is branched, as shown at 1-1 and 13. One branch 11 passes to the intake port 15 ofv a hydraulic pump cylinder 17, and a branch 13 passes to the intake port 19 of a second hydraulic pump cylinder 21.

Inlet check valves

23 and 25 are located in the branches 11 and '13, respectively.

The

hydraulic cylinders

17 and 21 constitute doubleacting hydraulic pump parts of a pressure booster 27. This booster includes an air cylinder 29 in which is a double-acting reciprocating piston 31 which carries on opposite sides

hydraulic plungers

33 and 35 operating in

cylinders

17 and 21, respectively. Thus the

plungers

33 and 35 reciprocate in the

hydraulic cylinders

17 and 21, respectively, forming what will be referred to as hy, draulic plunger pumps (.17, 33) and (21, 35) on oppo'- site sides of a double-acting air engine (29,31). The area of thepneumatic piston 31 exposed to air pressure is greater than the area of either of the ends of the

hydraulic plungers

33 and 35 exposed to hydraulic pres sure. Thus the booster 27 is constituted by a double? acting air engine constituted by the cylinder 291and a relatively large-area piston 31, driving opposite hydraulie pumps constituted by the parts (17, 33) and (21, 35), respectively having relatively small-area plungers. 33 ass tachable two-way shut-off hydraulic tilting (55, 5.7). The i male element '57 of the fitting is connected with a flexible hydraulic supply line 59 which leads to the inlet of a hydraulic tool to be served with hydraulic fluid under pressure. Further description of the elements of fitting (-55, 57) will be unnecessary, it suflicing to say that upon engaging

elements

55 and 57 fluid flow may take place, and upon disengaging them outflow from either

member

55 or 57 is prevented. A small (say, one-quart) accumulater 61 is branched from the line 47. This has an air pocket for preventing hydraulic hammer in known manner.

At numeral 63 is shown a hydraulic return line from the exhaust port of said tool. Line 63 ends in another female element 55' adapted to couple with another male element 57' of a quick-detachable two-way shut-elf fitting (55, '57); The relief valve 51 has a connection 65 back to the supply tank 3. The male-female relation between parts 55' and 57' is reversed relative to

elements

55, 57, in order to prevent mistakes in coupling the correct lines '59 and 63 to he lines 47 and 67, respectively. The male element '57 is also connected by a line 67 with the return line 635.

(69, 71) requires no further description because it is of I the same general nature as fittings (55, 57), (-55, 57'), except that itfcarries air when coupled but prevents escape of air from female element 71 when decoupled. In this case the male element 69 will contain no shut-oil check valve. This upon decoupling allows the pressure to exhaust from the booster 27. For example, with 80 p. s.i. air pressure available and 2800 p.s.i. hydraulic pressure desired, the pressurized area ratio of piston 31 to either plunger 33 or 35, is thirty-five to one t 'ni n l f 5 is ho a air s pp y i e ea ing rom the fitting 6 9 in 'whieh are located "in order an air filter 77, a pressure regulator 79 including the usual gauge, for reading regulated pressure, a l ubricator 83 and a manual flow-control needle valve 85 (having an operating handle 167),. Line 75 is branched, one part 87 extending to an inlet 89 of a two-position three-connection normal ly open directional valve 91. This valve 91 is shown in closed position in Fig. 8. Another branch 93 from supply line 75 leads to the inlet 95 of a two-position threeconnection normally closed directional valve 97. This valve is shown in its open position in Fig. 8.

Valves

91 and 97 are under control of air-operated pilot controls 99 and 101, respectively, air being movable to and released from them through pilot line 103.

Branches

105 and 107 lead from this line. Atthe left end oi the cylinder 29 is shown at numeral 109 a momentary c'ontact spring-returned two-way shut-off valve, which is normally closed, Thus branch 105 is connectiblethrough 109, to an exhaustport Z111 of valve 109. -At numeral 113 is shown another mechanically operated momentarycontact spring-returned two-way shut-off valve113 which is normally closed. Branch 197 connects with this valve 113 T e e r so h s a n t :5 i h i s pp e over a pilot supply line1-17 from the branch 93 of the supply l ne is; Numerals 1 19 and illustrate mechanical actuators fo

h a v

1, ,9 an 1. e p v Th se actua ors.

are adapted to be contacted by the piston 31 at theeni ls of its stroke so as alternately to actuate the

valves

109 and 113. When the piston '31 contacts actuator 1'19, valve 109 forms an exhaust connection to port 111 for pilot controls 99 and 101. When the piston '31 contacts actuator 121, valve 113 forms a pilot pressure connection through

lines

117 and 107, 103 to the pilot controls 99 and 101.

At the opposite ends of; the cylinder 29 are

air con nections

123 and 125, which lead through

valves

91 and 97, respectively, to a heat interchanger air loop 127. This loop connects both to the exhaust 129 of valve 9 1 and the exhaust 131 of valve 97.

Operation Operation is as follows, referring to Fig. 8:

Pressure enter over

lines

75, 93 to the open port of valve 97. This port is open because at this time air pressure over pilot line 117 has entered pilot control 101 through inlet port 115, valve 113 and

lines

107 and 103. It will be understood that at this time the actuator 121 has been momentarily contacted by piston 31, thus opening valve 113. The result is pressure flow through valve 97 and, line 125 to the right side of piston '31, driving it to the left. This forces hydraulic fluid under pressure from cylinder "17 via loop 41 and line 47 to the tool inlet line 59 (assuming that a coupling between parts '55 and 57 has previously been made). Return liquid from the tool flows through closed connection (55,57) through

lines

67 and, 65, back to the supply tank or reservoir 3. It will be noted that the hydraulic pressure supplied to the tool will be higher than the air pressure supplied to line 75 in the inverse ratio of the pressurized areas of pistons 3-1 and '33. Therefore, the. combined air-engine and hydraulie pump device 27 is injthe nature of a pressure booster, as stated. Its double actionand the action of accumulator 61, minimize pressure pulsations in tool line 59. Accumulater 61 further minimizes pressure, drop due to instantfaneous demand. n

As piston 31 proceeds to the left in its operation of hydraulic pump (17, 33), it exhausts air over line 123 through valve 91 to the air loop 127. Port 13-1 'of valve 97 is at this time closed. After the piston 31 has proceeded to the left for a full stroke, it momentarily contacts the actuator 119, thus connecting and exhausting pilot controls 99 and 101 through. lines 103, and valve 109 out, oi the exhaust 111, valve 109 being momentarily open d. f r he P pose by the a tuator 1519. Since pres: sure is exhausted from the pilot controls 99 and "101, the valves, 21 and 97 are set in their alternate. positions with he renownr ult-:- Air flows. from, th upp y line 7-5 through valve 91 and line 123 to the left of piston 31, driving it to the right. Exhaust from the right of piston 31 proceeds over line 125 through valve, 97 to loop 127. At this time, the port 129 of valve 91 is closed." The result is first to operate the hydraulic pump (21, 35), driving hydraulic fluid via loop 41 and line 47 to line 59. Thus for each cycle of movement, the tool receives two pulses of hydraulic pressure, the pressure variations of which are damped by the accumulator 61. Likewise, upon'each cycle oi operation, the air loop receives two pulses of exhaust air. This air is used for cooling purposes, air nozzle ports 133 being employed in the loop to direct expanding air 'over the coil 7. As shown in Figs. 6 and 7, this coil 7 is in a housing 135 forming a cooling chamber 137. The coil 7 is provided in the housing-135 with heat-radiating fins 139, the housing being provided with -a baffie 141 below which area series o'fi outle't lonv'ers In view of the above, it will be seen that the exhaust air in traveling from the booster 27 to the loop 127'has time forsome cooling by; radiation and convection.

, 1. .9r. er,,as h air escap om t e nozzles 133, i

hydraulic fluid iscooled. It will also beapparentthat when the hydraulic tool being supplied with fluid is shut oif, a'condition of equilibrium will be obtained inwh'ich the pressure built up in loop 41 and line 47 will stall the piston 31, the relief valve 51 being set at a high enough pressure value that this will occur. Thus the pumping system ceases movement as soon as the tool supplied therefor is shut off. This saves wear on parts by and eliminates the generation of heat in the hydraulic circuit during nonoperating periods. Thus also, in addition to the cooling efiected by the heat interchanger 9, additional cooling occurs during rest periods. As an example, suppose that 80 p.s.i. is admitted to line 75 through the pressure regulator 79.. As stated, the areas of the piston 31 and plungers33 and 35 are suchthat 2800 lbs. hydraulic pressure will be supplied over line 47 to the tool at the end of line 59. Then thepressure relief valve 51 would be set at, say, 3000 lbs. relief pressure. If the tool is shut off, the reciprocating system will stall at a pressure somewhere between 2800 p.s.i. and 3000 p.s.i. On the other hand, should someone change the setting of the pressure regulator 79 in, say, an attempt to drive a stalled tool by raising the air pressure applied to booster 27, no more than 3000 lbs. of pressure could be exerted, either upon the'lines of the system or the tool. It may be observed in this connection that an opening 153 is located in the cover 154 above'the location of the control element 156 of the regulator 79.

The

needle valves

53 and 85 control the tool operating speed atany given hydraulic pressure as determined by the setting of the air pressure regulator 79. Valve 53 also acts as a cut-olf of liquid supply to the hydraulic tools.

All of the parts thus far described are diagrammatically shown and numbered in Fig. 8. As many as may be of these parts are shown and correspondingly numbered in Figs. 1-5. All parts, including the

coupling parts

55, 57, 69, valve handles 165, 167 and the gauge 81, are combined as an assembly carried on the wheels 163 of the unit 1. All but said

parts

55, 57', 69, 165, 167 and 81 are surrounded by

side panels

147, 149,

end panels

151, 153 and the removable cover 154 (note cover screws 219). A handle 155 is attached as at -7 to bottom stiifener pieces 159. These pieces carry an axle 161 for a pair of supporting wheels 163. The air inlet coupling member 69 is exposed on the outside face of panel 147 and the

hydraulic coupling member

55, 55 are carried on the outside face of panel 151. The operating handle 165 for control valve 53 is also exposed on this panel. Likewise, the operating handle 167 of valve 85 is exposed on the outside face of panel 149. The face of gauge 81 is exposed on the outside of thepanel 153. The louvered outlets 143 are in the panel 149.

In view of the above, it will be apparent that the unit may be transported on wheels 163 by use of handle 155 to a point at which a hydraulic tool or tools are to be supplied with hydraulic fluid under pressure. The tool lines 59 and 63 are then coupled to the

lines

47 and 67, respectively, through the couplings (55, 57) and (55', 57). The available air hose 73 is coupled to line 75 through coupling (69, 71), whereupon the air engine component of booster 27 operates to generate and maintain static pressure in the hydraulic system. Then no further operation occurs until the tool valve is opened, whereupon the system starts at once at operating pressure and continue to operate, supplying the required pressure until the tool is again shut ofi, whereupon the system stops operating while the pressure is maintained. The cooling due to idle periods and due to the action of the heat interchanger 9 is eflfective to prevent overheating of the hydraulic fluid due to operation of the system and of the tool. Starting and stopping are instantaneous under full operating pressure, especially with the added efiect of the accumulator.

Figs. 9 and 10 show an alternative form of heat interchanger and Fig. 11 shows an alternative pneumatic;- -hydraulic circuit arrangement with which such a heat is substituted for'the two directional valves 91 and 97 a single directional valve 169 of the two-position, four-con- ,nection variety, which hasoppositely acting pilot controls 17.1, 173. The air supply line 75 is connected to an inlet .175 ofthe valve 169. Thevalve outlet isshown at 177 connected with an outlet line 179 leading to a heat interchanger 181 of the form show for example in Figs. 9

and 10. The heat interchanger as such will be described below.

At numeral 183 is a pilot lineleading from line 75 to a port 185 of a momentary-contact spring-returned threeway selector valve 187. -At numeral 189 is a pilot line leading from the supply line 75 to an inlet port 191 of a second momentary-contact spring-actuated three-way selector valve 193. The

valves

187 and 193 has

exhaust ports

195 and 197, respectively; As the piston 31 reciprocates, it alternately strikes the mechanical actuators 119. and 121 at the opposite ends of its stroke.

In the position of valve 169 shown in Fig. 11, air will flow to the left side of piston 31 through

lines

75 and 123. Air on therig'ht side of the piston is exhausted through the valve 169 via lines and 179 to and through the interchanger 181. When the piston strikes the right-hand'actuator 121, it sets selector valve 193 into a position connecting port 191 with a line 199 leading to the pilot control 173. This resets the valve 169, air also exhausting from the pilot control 171 over a line 201 to the exhaust port 195.

With the reverse position of valve 169, air is fed from line 75 to the right-hand side of the piston 31 over line 125. As the piston 31 moves to the left, air is exhausted through valve 169 over

lines

123 and 179 to the heat interchanger 181. Finally, when the piston 31 strikes the left-hand actuator 119, the valve 187 is reset, so that pressure flows from the pilot line 183 through the inlet to the pilot control 171 via pilot line 201. At this time, pilot control 173 exhausts over line 199 to 197. Otherwise the actuation of this alternative system is the same as that already described in connection with Fig. 8. However, the exhaust line 179 is not in the form of a loop but has a through connection with a heat interchanger such as shown in Figs. 9 and 10. In this case the air inlet connection is shown at 215 and outlet connection at 217, these being located in a double-walled shell 207. A heat-insulating and soundproofing filler 209 is located between the walls of the shell and additional like material 210 is infilled around the tubes 213, such as asbestos, glass wool, steel wool, fibre or other suitable packing.

. Within the shell 207 are headers 211 between which extend tubes 213. Hydraulic fluid flows from inlet 203 to outlet 205 through these tubes 213. Exhaust air flows through the material 210 around the tubes 213 from line 179 via the inlet and

outlet ports

215 and 217, respectively, effecting cooling. If desired, the material 210 in the shell may be omitted. Use of material 210 improves the diffusion of air around and into contact with the tubes 213 for efficient heat exchange. It also acts-as a condensate trap which upon reevaporation of the condensate improves the cooling. The advantage of this form of heat-transfer device is that it not only effects heat transfer but also acts to mufile exhaust puffs from the air engine.

Among the advantages of the invention are that a double-acting air engine having a reciprocating piston is directly coupled to the pump plungers, which in a simple manner minimizes surging by providing two plunger strokes per cycle. The direct connection between the reciprocating piston and the pump plungers, in view of the relatively large area of the piston exposed to air pressure and the relatively small areas of the pump strokes per cycle;

In view of the above, it will be seen that the several objects of theinvention are achieved and other advanf ta'geous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall beinterpreted as illustrativ'eand not in a limiting sense.

I claim: 7

A portable hydraulic'pres'sure generatingandholding unit for hydraulic lines of hydraulic tools and the like comprising a movable assembly of a liquid supply container, a pressure booster including coaxial alternately operable reciprocating hydraulic pumps having relatively small coaxial plungers and an air engine having a cylinder and a relatively large double-acting reciprocating air piston therein, which piston is attached to said plungers, each of said pumps having an inlet check valve and an outlet check valve, a first hydraulic connection from said container having branches respectively connecting with said inlet check valves, a second hydraulic connection serving as a pressure outlet and having branches respectively connecting with said outlet check valves, a normally closed air inlet device, partof which is on an air pressure line adapted to be opened upon connection ofsaid air pressure line, normally closed hydraulic outlet and return devices'adapted to be opened upon connection of said hydrauliclines, said second hydraulic connection ex tending to'said hydraulic outlet device, said hydraulic return device being hydraulically connected with said container, said air inlet device having branched air connections with said-cylinder on opposingsides of said piston, an air exhaust line having air outlet means, movable directional valve means interconnecting said branched air connections and said air exhaust line, control means for said directional valve means operated by said airoperated piston adapted in response to piston reciprocation alternatively to control air supply to said cylinder onopposed sides of said piston and to exhaust air from oppo'sitesides thereof to said air exhaust line, and means forming a chamber connected to receive exhaust air from said-air outletmeans, said chamber forming means being in heat-exchange relationship with a portion of said first hydraulic connection, thereby to form a heat interchanger between the hydraulic fluid and air exhaust.

References Cited in the file of this patent UNITED STATES PATENTS