US2867923A

US2867923A - Rotary pressing machine

Info

Publication number: US2867923A
Application number: US572020A
Authority: US
Inventors: Ole H Langen
Original assignee: Unipress Co Inc
Current assignee: Unipress Co Inc
Priority date: 1956-03-16
Filing date: 1956-03-16
Publication date: 1959-01-13
Anticipated expiration: 1976-01-13

Description

Jan. 13, 1959 oI`H.-| ANGEN 2,867,923

` ROTARY PRESSING MACHINE Filed march 16, 195e 2 'sheets-sheet 1 Jan. 13, 1959 o. H. LANc-sEN` 867;923

ROTARY PREssING MACHINE Filed March l16, 195e 2 sheets-sheet 2 155 m Kum INVENToR. ou. H. LANGEN '-BYWWW United States Patent O ROTARY PRESSING MACHINE Ole H. Langen, Minneapolis, Minn., assignor to The Unipress Company, Incorporated, Minneapolis, Minn., a corporation of Minnesota Application March 16, 1956, Serial No. 572,020

13 Claims. (Cl. 258-22) This invention relates to improvements' in rotary pressing machines of the type having a plurality of'individual pressing machines mounted for rotation on a vertical axis. Such rotary pressing machines are exempliied in Patent 2,669,044 and various other patents of the prior art.

All modern prior art pressing machines of this typey and exemplified in the aforesaid patent utilize separate individual presses of the type having steam heated presser heads and usually also have steam heated bucks. The mechanism for moving the head against the buck for pressing is almost always an air motor suitably controlled.

Since the individual presses are collectively mounted on a rotary frame, it is necessary to provide concentric pipes and rotary gland connections for the air required for the presses and for the steam supply line and condensate return line. Such rotary gland connections add to the cost; and they are frequently difficult to maintain in operation. In addition, it is sometimes desirable to add a rotary pressing machine in an establishment having a limited steam supply or one where connections to an existing steam supply may be diflicult.

It is an object of the present invention to provide an improved rotary pressing machine wherein the diiiiculty in respect to cost of construction or maintenance of the multiple pipe rotary gland is obviated.

It is another object of the invention to provide an improved pressing machine the aforesaid rotary type having a self-contained steam supply.

It is another object of the invention to provide an improved pressing machine wherein the heat supply is generated on the rotary portions of the rotary frame and rotates with the presses in contra-distinction to heat supply generation exterior to the rotary frame and conducted thru rotary glands to the several presses on -the rotary frame.

It is another object of the invention to provide an. 'improved pressing machine wherein the heat supply is generated in the heads and bucks of the presses.

It is another object of the invention to provide an improved pressing machine wherein a boiler is mounted upon and rotates with the rotary frame and steam is conducted from the boiler to each of the presses upon the rotary frame and from each of the presses the condensate is returned to said boiler.

Other and further objects are those inherent in the invention herein illustrated, described and claimed.

The invention is illustrated with reference to the drawings in which:

Figure l is a plan view of rotary press which is illustrative of the invention;

Figure 2 is a vertical sectional view partly schematic, of the pressing machine shown in Figure 1, this view being taken along the line and in the direction of the arrows 2-2 of Figure 1',

Figure 3 is a vertical sectional view, similar to Figform of v,the invention;

Figure 4 is a vertical sectional view, similar to Figure 2 and partially schematic, showing a second modified form of the invention;

Figure 5 is a fragmentary enlarged sectional schematic View of a portion of the pressing machine bucks or heads, of the machine shown in Figure 4.

Throughout the drawings corresponding numerals refer to the same parts.

In general it may be stated that the pressing machines of the general type of which the present invention is an improvement consists of a rotary turntable oflow elevation that is adapted to be placed on the door and upon which there are mounted a plurality -of individual pressing machines. The pressing machines are of the laundry or garment pressing type and may have the same or diiferent types of bucks and heads for pressing the same or different portions of garments or laundry items. While pressing machines of this type may be built as a unitary structure, for ease of manufacture and reduction in cost it has been found that ordinary individual air driven, steam heated pressing machines may be used to advantage, such individual pressing machines being mounted in regularly spaced relationship around the periphery of the rotary turntable. In such mechanical organization the presses are thus rotated one at a time in front of an operator station. At the operator station the press is automatically controlled by its rotary movement so as to actuate the press to open-press position and the operator may, without moving fromher position, remove the pressed garment and lay an unpressed garment on the buck. Usually the rotation of the press is continuous, the removal of the pressed garment and laying of an unpressed garment on the buck is eected while the pressing machine moves at its regular rate by the operator station. Then as each press on the rotary turntable progresses along its'rotary path of'motion it reaches a position adjacent to the operator station where provision is made for automatically actuating controls of the press to cause the presser head thereof to move against the buck into pressing relationship therewith. The actuation of the controls may be accomplished by various means, such as cams that are mounted on the tio-or or upon supports and which are engaged by appropriate mechanisms on `the presses as it moves by a predetermined station, which is known as the closing station. The press automatically closes and then remains closed as it continues its course of travel around its circular path of motion, being carried around by the rotary turntable, and at a predetermined station, known as the opening station, appropriate controls are actuated by cams or other mechanisms, such as timers, so as to cause the press to open, and it then is in an open condition when it again reaches the operator station. g y

It is in this class of pressing machines, of which the invention hereinafter described, constitutes improvements.

`For purposes of illustration, but not by Way of limitation there is herein illustrated a rotary pressing machine of the type shown in the Patent 2,669,044.

4 Referring to the drawings, particularly Figures l and 2, the pressing machine includes a central floor plate 10 which is adapted to be placed or bolted upon the oor 11 on which the pressing machine is installed. Upon the plate 10 there is a central stationary pivot 12. The pivot shaft 12 which is hollow, serves to support a suitable ball or sleeve bearings 18 which is mounted in the main flange 16 of the circular rotary frame plate 17 constituting the turntable. The bearing 18 may also serve as a thrust bearing so to receive the weight load at'the center of the rotary turntable 17. The plate 17 is preferably of circular shape and near its periphery it is reinforced by ring channels 20 and 21 which are positioned so that their flanges are oppositely directed and are of and the wheels 22 may run directly .upon the iloor 11 where the oor has sufficient evenness. Where the installation is made on a rough or uneven oor 11, it is preferable to place a circular sheet metal track 24 on the oor along the path where the wheels 22 track. The axis Vof each of the wheels 22 is radial in respect to the centralpivot axis 12.

For rotating the circular or turntable 17-20--2122 and all elements carried thereon, there is yprovided a belt` 25 which may be a chain belt, as shown in Figure 1, which passes over a pulley 26 that is mounted upon radial arm 27, the arm being pivoted at 2S to the floor. An adjustment screw 30 mounted in the stationary bracket 31 is positioned so as to bear against the arm 27 and move it arcuately and thus permit tightening or loosening of the belt 25. The belt 25 also runs over the driven pulley 32. The pulley 32 rotates at slow speed and is preferably driven by an electric motor 34 through a gear` box. It is preferable to use a motor 34 which is capable ofrspeed variations, such as a wound-rotor repulsion in- .duction motor, a shunt type direct current motork or the It is perfectly feasible to utilize an air driven like. motor 34 of constant or variable speed, where such is desired. The controls for motor 34 are appropriately selected for controlling its speed and operation.

i Upon the rotary base 17 thereare mounted a plurality -of pressing machines generally designated A, B, C and D in Figures 1 and 2. Any suitable number of pressingv vmachines greater than one may be utilized, depending upon the capacity of the unit and the type of work desired to be done by means of the installation. Four ment of the invention and are spaced evenlyaround the rotary frame plate 17. The rotation of the frame plate 17 is in the direction of the arrow 35 and rotation of the drive pulley 32 is shown by the arrow 36l An operator station indicated by the floor pad 37 extends through approximately one-quarter of the circular path of motionof the floor plate 17 and presses A-D mounted thereon. Adjacent the terminating edge 38 of the operator station, there is provided a protective guard 40 which likewise extends through approximately one-quarter of the path of rotation of the oor-plate. 17 and the presses mounted thereon. The guard 4G roughly denes the closing station, it being understood that the guard extends somewhat ahead of and behind the posltion to which the presses close at the closing station and is sufiiciently high so as adequately to safeguard any person from introducing members of his body into the press while the press is closing. From the termlnation of the closing station, which is at the position approximately 4() pressing machines are shown in the illustrated embodi` 4 as well as emergency opening controls for all presses may be located, convenient to the operator.

The presses A-D (or any number which are mounted upon the rotary floor plate 17), may be of any desired individually power driven presses. Present day presses are usually air `driven and in the embodiment of the invention herein illustrated, the presses A-D are of the multiple air-cylinder type shown in Patent Re. 22,041 although it is to be understood that any suitable air or other power driven press may be utilized. Thus, for example, the presses A-D can be single air-cylinder presses of which'the type shown in Patent 2,265,449 is exemplary, or they can be multiple air-cylinder presses.

In the exemplified showing of the invention illustrated in Figure 2, each of the pressing machines includes a frame 52 which is suitably attached to the circular revolving frame plate 17. The type of presses illustrated is a two-cylinder press, but as hereinbefore stated,this is merely exemplary of any type of power actuated presses that may be used. In the presses shown, 'each has a press frame and yupon the frame 52 there is mounted a stationary buck 54 and a presser arm 55 which is pivoted at 56. The presserarm carries a presser head 57 which is movable from an open position (as shown for press A at the left in Figure 2), to the closed position (as shown for press D at the right-in Figure 2). The movement of the press from open to closed positionand from closed to open position isaccomplished by means of an air or other fluid motors suitably controlled by push-button type valves.

In PatentRe. 22,041, which explains theoperation of presses of this type, the air-cylinders for operating the press are energized through two-hand control valves that are (in case of an individually used pressing machine), located near the front of the vpressing machine on the work table beneath thebucks. Y In the present illustration these two valves (corresponding to the twovhand control'valves) are located at 75 and 76 near the base of the press and whenthey are operated, air under pressure is introduced from the air supply pipe for operating the press.

Valves

75 and 76 are normally closed by spring action Vbut when both are open, air is transmitted shown by press D in Figure 1, and continuing in thev l direction of arrow 35, there is a portion of the path of motion during which the pressing part of the cycle takes place. During this portion of the cycle the pressing head is closed down upon the buck. The opening station is between the position in which press B is shown in Figure l, which is still closed, and the leading edge 41 of the operator stations.

lThe closing station actuator is shown generally at 42 and the opening station actuator is shown generally at 45.

vAdjacent the leading edge of the guard 40 there is a control panel generally designated 46, in which the on- :olrlcontrols of motor 34 and speed controls therefor,

therethrough and thence` to a closing pilot cylinder of4 the press (not shown) which, when operated, causes the press to close the press.

Opening of the press isoccasioned by the operation ofa release valve 82 which in Patent Re. 22,041, is likewise mounted on the work table 74 but here is mounted near the bottomof the press lframe. Valve 82 is normally closed by spring action, but when actuated air is admitted through it, the appropriate press controls are operated for opening the press. The foregoing controls are described in greater detail in Patent Re. 22,041, and it is tobe understood Vthat any suitable mode of control for the presses A, B, C and-D may be utilized, depending upon the style of the press,A and that the specific illustration herein given is therefore only exemplary.

Each of the presses AB, C and D of the rotary pressing is therefore provided with a set of closing valves (oractuators) corresponding to 75 and 76 and with an fopening or release valve (or actuator) corresponding to valve 82. These may be located at any convenient place on the press or on the rotary frame 17. For example, they may be located at the front lower left portion of each press as illustrated inthe present exemplified form of theinvention or at any place on the rotating frame 17 orV parts vmovable therewith so that thevalves may be operated by stationary stops or cams yas the presses move along Ytheir circular paths .of motion. Thus,

V valves

75, 76 and 82 may be located on the frame V17 so as tobe within the ,contines of thecircularring channel21 so as to be operated by cams thereunder as shown in Patent 2,632,965. The. criterion is to have eachpress close after it has reached a ,safe location .within at prescribed space (as within the'guard 4(1).y The closinglcams arelocatcd `genaues accordingly. The criterion is also to have each press open as it comes to the operation station and the opening cam is located accordingly. y

Thus the press

closing control valves

75 and 76 here illustrated, are for each press positioned so that their operating stems are located to be engaged by a pair of

operating cams

86 and 87 that are mounted on pedestal 88 in the housing 42 shown in Figure 1. As the rotary turntable moves each press by the closing station v42, Figure 1, the

cams

86 and 87 engage the stems of the

valves

75 and 76 of each press and thereby causeactuation of the then open press to closed condition. It may be pointed out thatv two

valves

75 and 76 are utilized in order that greater safety for the device may be obtained. This prevents accidental operation of the press in the event anyone should accidentally kick one of the

valves

75 or 76.

Thus, as each press reaches the closing station 42 the

cams

86 and 87 cause actuation of the press and the presser head 57 closes upon buck 54. The continued rotation of the turntable 17 carries the then closed press in the direction of arrow 35 and the pressing action takes place until the operation controls of the press are brought adjacent the opening station 45, at which place a single cam 90 which is mounted upon a pedestal under the cover 45, actuates the operating stem of the release valve 82, thereby causing each press to open as it moves by the opening station 45. The thus opened press continues around through the operation station 37 The operator removes the pressed garment and lays an unpressed or damp garment on the buck while the rotation is continued, or two operators, if desired, may be at the operating station J37, one who will remove the garments and another to place the unpressed garments on the buck. The then open press with the unpressed garment on the buck then continues around to the station 42 where closure of the pres is occasioned as previously described. i

it is in respect to rotary multiple pressing machines ofthe aforesaid generally described type that the present invention forms an improvement.

In such pressing machines uid connections are required for conducting three fluids between the stationary floor and the rotary pressing machine turntable and the presses carried thereby. These fluids are (l) air, for motivating the press operating motors, (2) steam, for heating the presser heads and/or bucks, and (3) steam condensate return. Since these fluid conduits must all pass from a stationary location to a rotary location this has necessitated concentric pipes and glands, of which one type is shown in Patent 2,497,128. Such concentric pipe gland devices are expensive to build and sometimes difcult to maintain.

According to the present'invention the number of concentric iiuid conduits is reduced by providing a heat generator (or generators) on the rotary frame itself and by then merely providing a heat source fluid or power supply line connection from the stationary to the rotary portions of the device. Several modes of accomplishing this broad result are possible and will now be described.

Referring to Figures land 2, in this illustrative form of the invention, a small kheat generator which is in the form of a gas red boiler is illustrated at 100 and mounted by supports (not shown), so as to turn with the presses A-D on the rotary frame 17. The boiler 100 is provided with four steam outlets 101A-101D, one leading to the steamline of each .of the presses A-D respectively and four condensate returnpipes, of which those for presses A, Dand B respectively are shown in Figure 2 and indicated by numerals 102A, 102D and 102B. The net effect is that the boiler 100 supplies steam to and receives back condensate from each of the presses A-D without the necessity of providing any rotary gland connection for either the steam line 0r the condensate return line. The heat supply fluid, here illustrated as gas, but equally well, oil, can likewise be thru a solid pipe line, here the line 103, which terminates at stationary burner 104. The burner is stationary and the heated gases therefrom simply pass up thru the internal tubing (not illustrated), of the boiler and then vent thru boiler stack pipe 105, which rotates with the boiler. The stack exhausts into a stationary hood 106 on the lower end of flue 107. Thus, without rotary gland connections for steam, condensate fuel or flue, it is pcssible to supply the needed heat to the presses.

The air pressure supply is provided by way of pipe 108 which does have a rotary gland 109 in it, the gas (or oil) fuel supply line passing thru the gland, as is well known, from the housing of gland 109, which revolves with the turntable air lines lead olf to the various presses, two of these being shown at 110B and 110D. Since the fuel supply pipe 103 is not hot (as steam would be), there is no difiiculty experienced in maintaining the gland 109 in effective operating condition.

Figure 3 illustrates another slightly modified form of the invention exactly like that shown land described with reference to Figures 1 and 2, except as follows: Whereas in the modication shown in Figures l and 2, the heat supply iiuid is gas or oil (suppliedvia pipe 103), in Figure 3, the heat for boiler is supplied by means of an electric heater, schematically illustrated at 120. The heater will be understood to be suitable attached to boiler 100 or may be of the immersion type and it is supplied by

electrical leads

121 and 122 attached to suitable brushes supported by the insulated members (not shown) on the turntable framing. The brushes bear against the

stationary slip rings

123 and 124 respectively which are mounted upon the insulator 125 which is in turn carried by the stationary conduit 126, which is similar to the stationary fuel supply pipe 103 of Figure 2;. The electrical supply wires L1 and L2 pass up lthru pipe 126 and are respectively connected to the (stationary)

slip rings

123 and 124. Again, as in Figure 2, the pipe 126 (similarly to pipe 103 and Figure 2) has an air supply pipe 108 around it terminating at rotary air gland 109, from which air supply leads extend to the several presses. The pipe connections from boiler 100 in Figure 3 are lshown in dotted lines as being steam supply lines leading from the upper part of the boiler to each of the heads and bucks and condensate return lines vfrom each of the bucks and heads to the boiler. These are all solidpipe connections and involve no rotary gland elements but contain a flexible portion leading to the presser head and buck elements, as is well known in the pressing machine art` Thus in the Figure 3 modification the heat supply to the rotary presses is accomplished with only one simple two line slip-ring.

In the modification shown in Figures 4 and 5 the bucks and heads of each of the presses on the rotary frame are directly heated by immersion type electric heating elements or jby dry-type electric heating elements, lthe former being preferred.

In Figure 4, the electrical ksupply is via lines L1 and L2 which pass up thru stationary conduit and connect to stationary slip-

rings

123 and 124 which are mounted on insulating block 125 which is in turn mounted on pipe 126. Here again pipe 126 is concentric with air supply pipe- 108 thru which pipe 126 passes. Pipe 108 terminates at rotary air gland 109 which is connected thru air leads to the several presses. Brushes 123A and 124A are mounted on an insulating support (not shown) on the rotary turntable 17 or on one of the presses carried thereby and from these brushes the

lines

130 and 131 extend and serve `as feeders to which are connected the branches extending to the electrical heating elements of each buck and each head. Since the mode of heat application to the bucks and heads is the same for all heads and' bucks only one exemplary (head) heating element need be described. Thus for head 57 of press D there is an immersion type heater element 142 vhaving

external terminals

132 and 133 to which flexible leads 134 and v1135 are respectively connected, thru a control switch, as

will be described. These exible' leads extend backto the

supply line feeders

131 and 130 respectively.

Figure illustrates schematically a fragment of the wall of the presser head 57,'it being understood that the presser head steam chest is hollow Iand closed. The interior (or wet) side of the presser head wall (steam chest) is at 57W and the exterior (or dry) side is at 57D. The presserhead of course has a pressing surface, 57P (see Figure 4), which is curved and polished. The presser head and its steam chest (or the buck and its chest) in effect form a container, the exterior surface of one side of which is the (heated) pressing surface. Ordinarily, in steam heated presses, high pressure steam is introduced into the steam chest, thereby to heat its pressing surface. thermic iiuid, preferably one capable ofbeing volatilized at the temperaturesrequired for pressing, is placed'in the presser head so as partially to fill it and the airover such fluid is exhausted or partially exhausted. This in elect converts the steam chest into a small, closed, low pressure boiler. At some convenient surface of the presser head (for example the top surfaces 57D, and at any convenient place on the buck chest), there is provided a thickened boss, suitably drilled and tapped to rej ceive a pressure gauge 140, the threaded mounting tube 141 of the electrical heater 142, a pressure (or temperature) 'actuated electric switch 143 and a fusible plug nects to one terminal 145 of switch 143, and from the other terminal 146 an intermediate connection 147 leads t to terminal 132 of heater 140-142. Electric line 135 is connected to the other terminal 133 of the electric heater. Switch 143 is normally closed and is calibrated to open at a desired temperature of operation of the pressure head 57. At such temperature the fluid lling in the presser head cavity is vaporized and hence the heat is communicated to all surfaces of the head. The fusible plug 144 is selected to relieve at a predetermined excess temperature.

The pressure heads and bucks are similarly constructed, each being provided with the controls as shown in Figure 5. Hence heat is Isupplied to all required pressing elements of the rotary presses without the necessity of steam 'and condensate lines containing yrotary gland elements.

The form of the invention shown and described must be considered only as illustrative. Many Variations within the scope of the invention illustrated, described and claimed will be apparent to those skilled in the art, and the invention is therefore not to be limited except as stated in the appended claims.

What I claim is:

l. In a rotary pressing machine having a frame mounted for rotation about a xed axis on a stationary base, said frame having thereon a plurality of separate presses each having cooperating pressing elements, at least one of which is heated, and compressed air power mechanism connected to said elements and controls therefor, for moving them into engagement for cooperating pressing action, the improvement comprising heat generator means mounted on the rotary frame for atleast one of the pressing elements of each press, and a supply line co-axial with the axis of rotation of said rotary frame and extending from said stationary base and connected to said heat generator means for conducting a heatenergy supply to said heat generator means on said rotary frame.

2. The combination set forth in claim l further characterized in that an air pressure supply pipeis provided extending co-axially with said fixed axis and said supply line, said supply pipe including arotary gland, said sup- Here, a charge of water or other` pressure relief element 144. The electric line 134 con- 30 ply pipe 'being connected tothe power mechanism of each press on the rotary frame.

3. The combination set forth in 'claim 1 further characterized in that said heat generator means is a fluid boiler having connection to the heated pressing element of each press and saidl supply line comprises a fluid fuel supply pipe terminating at a uid fuel burner under said boiler.

y4. The combination set forth in claim 1 further characterized in that said heat generator means is a uid boiler having connection to the heated pressing element of each press and said supply line comprises electrical circuits connected to an electric heater mounted for heating said boiler.

5. The combination set forth in claim 4 further characterized in that said electrical circuits include rotary connections and said electric heater is mounted xedly on said boiler.

6. The combination set forth in claim 1 further characterized in that said heat generator means comprises a separate heating element for each heated pressing element of each press and an electric circuit including a rotary connection is provided extending from said stationary base to each such separate heatingelement.

7. In a rotary pressing machine having a frame mounted for rotation about a fixed axis on a stationary base, said frame having thereon a plurality of separate presses each having acooperating stationary buck element and presser head element, at least one of which is heated, said head element being movably mounted on the press for cooperating pressing engagement with the buck element and a compressed air motor connected thru controls to said presser head element for moving the same, the improvement comprising a boiler mounted on the rotary frame for rotation therewith, said boiler being connected to the heated element of each press, and a fuel supply line extending co-axially with the axis of rotation of the rotary frame and terminating at a fuel burner positioned for heating theboiler. l

8'. The combination of claim 7 further characterized in that a flue is arranged above the boiler for receiving the flue gases therefrom.

9. The combination of claim 7 further characterized in that said fuel supply lnevextends co-axially within a compressed air supply pipe having a rotaryv gland thereon which is connected to the compressed air motor of each press. l

l0. In a rotary pressing machine having a frame mounted for rotation about a fixed axis on a stationary base, said frame havingl thereon a plurality of separate presses each having a cooperating stationary buck element and presser head element, at least one of which is heated, said head element being movably mounted on the press for cooperatingpressing engagement with the buck element and a compressed air motor connected thru controls to said pressure head element for moving the same, the improvement comprising a boiler mounted on the rotaryframe for rotation therewith, said boiler being connected to the heated element of each press, an electrical heater for said boiler,.slip rings mounted co-axially with the axis of said rotary frame, electrical supply leads terminating at said slip rings and electrical connections from the slip-rings to said electrical heater.

l1. In a rotary pressing machine having a frame mounted for rotation about axed axis on a stationary base, said frame having thereon a`plurality of separate presses each having a cooperating stationary buck element and presser head element, at least one of which is heated, saidhead element being movably mounted on nected to said chamber for opening and closing a circuit in accordance with the temperature of said chamber, an electric circuit co-axial with the axis of rotation of said rotary frame and connected thru the electric switch of each chamber to the electrical heater of said chamber.

12. The combination of claim 11 further characterized in that a pressure gauge is provided for each chamber. 13. In a rotary pressing machine having a frame mounted for rotation about a fixed axis on a stationary base, said frame having thereon a plurality of separate presses each having co-operating pressing elements, one of which has a heatable pressing surface, and compressed air power mechanism connected to said elements and controls therefor, for moving them into engagement for cooperating pressing action, the improvement comprising 15 2,497,128

10 a steam boiler positioned for rotation with said frame and located thereon and in steam ow communication with said heatable pressing surface for heating the same, a stationry supply line on the base and extending along the axis of rotation of the boiler and supplying a heat producing media thereto, and means connected with the supply line for producing and transmitting the heat to the boiler.

References Cited in the le of this patent UNITED STATES PATENTS 1,169,873 Sanborn Feb. 1, 1916 1,250,420 Betker Dec. 18, 1917 Leef Feb. 14, 1950