US1807231A - Elevator door operating mechanism - Google Patents

Elevator door operating mechanism Download PDF

Info

Publication number
US1807231A
US1807231A US674848A US67484823A US1807231A US 1807231 A US1807231 A US 1807231A US 674848 A US674848 A US 674848A US 67484823 A US67484823 A US 67484823A US 1807231 A US1807231 A US 1807231A
Authority
US
United States
Prior art keywords
cylinder
valve
door
piston
operating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US674848A
Inventor
Weeks William Wallace
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ELEVATOR SUPPLIES CO Inc
ELEVATOR SUPPLIES COMPANY Inc
Original Assignee
ELEVATOR SUPPLIES CO Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ELEVATOR SUPPLIES CO Inc filed Critical ELEVATOR SUPPLIES CO Inc
Priority to US674848A priority Critical patent/US1807231A/en
Application granted granted Critical
Publication of US1807231A publication Critical patent/US1807231A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B66HOISTING; LIFTING; HAULING
    • B66BELEVATORS; ESCALATORS OR MOVING WALKWAYS
    • B66B13/00Doors, gates, or other apparatus controlling access to, or exit from, cages or lift well landings
    • B66B13/02Door or gate operation
    • B66B13/06Door or gate operation of sliding doors
    • B66B13/08Door or gate operation of sliding doors guided for horizontal movement

Description

4 Sheets-Sheet 1 INVENTOR Maw 1d. MM,

WWW.

ATTORNEYS W. W. WEEKS Filed Nov. 15, 1923 ELEVATOR DOOR OPERATING MECHANISM May 26, 1931.

"DE-d May 26, 1931. w. w. WEEKS ELEVATOR DOOR OPERATI ENG MECHANISM Filed Nov. 15, 1923 4 Sheets-Sheet 2 RM W mm /m W WM m w MW 3 $8 3 0n. a n \N E ww m \\X May 26, 1931.

w. w. WEEKS 1,807,231

ELEVATOR DOOR OPERATING MECHANISM Filed Nov. 15, 1923 4 Sheets-Sheet 3 70 INVENTOR (Va 5&0 (a [M 7&04/124 ATTORNEYS May 26, 1931. w. w. WEEKS ELEVATOR DOOR OPERATING MECHANISM Filed Nov. 15, 1923 4 SheetsSheet 4 INVENTOR MMwl/lauwb ATTORNEY Patented May 26, 1931 UNITED. s'rA'ras PATENT oFFrcr.

WIILIAI WALLACE WEEKS, OF BROOKLYN, NEW YORK, QSSIGNOR TO ELEVATOR SUP- IPLIES OOMIPANY, INC A CORPORATION OF NEW JERSEY ELEVATOR DOOR OPERATING MECHANISM Application filed November 15, 1923. Serial No. 674,848.

- which the opening and closing of the doors is under control of the operator by the manipulation of a valve or valves to admit pressure fluid to, and exhaust pressure fluid from,

the operating cylinders.

' In devices for operating elevator doors, in which the movement of the device is pneumatically cushioned to cushion the movements of the elevator door during the opening and closing thereof, considerable difliculty has been experienced when it has been attempted to speed up operation. It has been found that with the-use of increased pressure of the operating fluid to operate the elevator doors, more rapidly, a jarring or reciprocating movement of the door takes place, or a rebounding of the door occurs in a portion of its movement, because of excessive pressure built up in the cushioning fluid. It appears that the excessive pressure is built up during cushioning, because of the momentum gained by the door in the opening or closing movement, which results in a building up of pressure in excess of the operating pressure.

One object of the present invention is to overcome the above-defects and improve the construction of elevator door operating mechanisms in such a manner as to permita rapid operation of the mechanism without causing rebounding or oscillating movement of the elevator door.

In the form of elevator door operating mechanisms in which two operating cylin ders are employed, a considerable loss of power occurs due to leakage of compressed air while the door is in closed position, due

to the fact that the full pressure of air or time the door is in inoperative or closed position. Another object of the present invention is to provide a mechanism in which the above and other improvements are combined to attain an efiicient and rapidly operating elevator'door operating device. With these and other objects in view, the invention comprises the features hereinafter described and more particularly defined in the claims.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a View in elevation of the improved door operating mechanism, shown in the position corresponding to that in which the elevator door, to which it is adapted to be connected, is closed;

Fig. 2 is a view similar to that of Fig. 1, showing the apparatus in the position corres onding to the open position of the elevator oor;

Fig. 3 is an enlarged vertical section of the mechanism in which the parts are in the relative positions corresponding to the closed position of the elevator door, showing the operating valve controlling admission and exhaust to and from the operating cylinders,

and also the shut-off valve and mechanism connected therewith which serve to cut off communication of pressure fluid with the door closing cylinder when the door is in closed position;

Fig. 4 is a detail plan view of the operating valve, taken on the line 4-4, Fig. 3;

Fig. 5 is a sectional View taken on the line 5-5, Fig. 4;

Fig. 6 is an enlarged end View of the device taken from the right in Fig. 1; and

Figure 7 is a view illustrating how the device may be mounted for the operation of elevator doors.

In elevator door operating mechanisms in which compressed air is employed to operate a mechanism of the general form shown in the drawings, it is preferable to connect the piston rods, or parts movable therewith, to swinging arms or the toggle levers of the elevator doors and to mount the cylinder or cylinders by suitable means to a part of the elevator shaft, preferably over the elevator I shaft doors when it is'to be used for oper- The preferred form of the invention comprises two cylinder casings 2, 4, which" are screwed into or otherwise attached to a valve block or coupling member 6, which is preferably adapted to contain an operating valve to control the admission and exhaust to and from the cylinders. The outer ends of the cylinders are supported on suitable frames 8,

10, which are preferably constructe dsso as to contain openings in which guide rods 12, 14

are adapted to slide during the operation of the device. The guide rods 12, 14 are preferably connected by means oftransverse connecting members 16, 18 to piston rod? 24, 26, the piston rods being connected to pistons 28, 30 adapted to slide in cylinders-2, 4, .respectively. The ends of the cylinders'are preferablyv covered by means of cylinder heads or caps 20, 22, having openings therein through which piston rods 24, 26 pass. The pistons, piston rods, and guide rods are preferably connected to the swinging arms or toggle levers of the elevator door or doors to be operated by means-of a link or links 34 which may be connected thereto at any suitable point, such as at 32, at which the transverse members 16, 18 are connected to the guide rods 12-and 14 respectively. In the cylinder casing 2 is an exhaust port or ports 36 through which air or other oper ating fluid may be exhausted during a portion of the piston stroke, as will be hereinafter explained. The port is suitably connected to an exhaust pipe 38 by means of a casing 40 having a passageway or port 42 therein. In the cylinder 4 is a similar exhaust port 44 which communicates with an exhaust pipe 46 through an opening or port 50 in a housing or casing 48 by means of which pressure fluid may be exhausted from the cylinder 4 during the closing movement of the elevator door. From the exhaust pipes 38 and 46 pressure fluid is conducted through suitable ports in the valve housing or coupling member 6, as will behereinafter described, and passes to an exhaust pipe 52 preferably into the atmosphere through an exhaust mufller 54, shown more particularly in Figs. 1 and 2.

In order to admit pressure fluid to the cylinders to operate the pistons and the mechanism connected therewith, a pipe 56 leading from the source of pressure fluid supply is connected0 to suitable passageways in the housing 6 containing the operating valve. It is preferable to control both admission to accomplish this a valve 58, in which are two separate passages or passageways 60, 62 is provided, by means of which the exhaust pipe and admission pipe may be alternately connected'with the cylinders 2 and 4 to attain admission of pressure fluid to andexhaust of pressure fluid from the cylinders. The valve 58 is suitably mounted in the coupling member or valve housing 6 so as to be under the control of a valve stem 64, as shown in Figs. 3 and 5, to which may be connected an arm or link member 66 (Fig. 2) which may 'be connected through linkages to an operating handle of any desired form. The arm 66 is preferably connected to a connecting rod or arm 68 which is in turn connected to a lever 70 pivoted at a fulcrum or pivot 72,

attached preferably to a stationary part of the frame. To the lever 70 isconnected an arm 74 which may be directly connected to the operating handle, by means of which the operation of the valve 58 is controlled.

In order to lock the door and mechanism When'the door is inclosed position, a latch 76 is provided which is adapted to look when the door is closed and to be opened when the operating handle is moved so as to admit pressure fluid to "open the door. A lug or projection 78 is provided on the lever 70, which is adapted to contact with a projection or lug 80 on the latch 76 when the operating lever is moved into position to admit air or operating fluid to open the door or doors to which t e mechanism is connected, the lever 70 is turned causin the latch to raise out of contact with the olding means 82. The locking means 82 for the latch is preferably mounted on the transverse member may be connected at one end to the link member 68, and at the other end to the frame member 8 by means of which the operating lever will be brought back to the position corresponding to the closed position of the elevator after operation of the lever to admit pressure fluid to one of the cylinders.

Connected to the coupling member or valve housing 6, so as to communicate with the ends of the operating cylinders 2 and 4, are relief valves 86, 88 by means of which the fluid pressure in the cylinders during the cushioning of the pistons and the parts connected thereto may be maintained below a predetermined value. By this means, cushioning fluid at the ends of the cylinders will be exhausted to the atmosphere at the ends of the strokes of the pistons in the respective cylinders, and will prevent jarring, rebounding, or oscillating movement of the pistons and parts connected therewith. The

relief valves preferably comprise a valve cas- 1 ing 90 (Fig. 5) which may be screwed into or otherwise attached to the coupling memher 6, and a spring casing 102 adapted to hold a regulating spring for the valve. In

the part 90 is a passageway 92 which is enl ll larged in the upper portion of the casing 90 to form a, conical seat 94 in which a ball 96 is adapted to seat and which may be held in place by means of a cage or holding member 98. The valve holding member 98 is forced downwardly against the,ball by means means of which also any desired fluid pressure may be attained during the cushioning action. If during the cushioning, which takes place through the trapping o a residual amount of pressure fluid, the pressure exceeds that corresponding to the set of the spring-100, then the bal 96 will be raimd from its seat and permit exhaust fluid from the end of the cylinder until the ressure corresponding to that determined y the pressure of the spring 100 is attained in the cylinder.

In order to provide means whereby, when the pressure fluid has been admitted to the cylinder 2 to return the piston and parts connected, thereto to the position corresponding to closed position of the-elevator door, the pressure of the fluid may not be maintained in the cylinder until the door is again operated, passage'106 is provided in which is a valve 108, preferably conical in form, which is so mounted as to be closed when the door is in closed position. By this means communicafalls when in contact with the corresponding part of the guide rod. The valve stem 110 is adapted to pass through a bushing 116, serving as a guide for the valve stem, and serving also as a seat for a spring 118 by means of which the valve is forced to its seat when the roller 112 passes into the depression 114. The tension of the spring 118 may be regulated by suitably adjusting the position of the bushing 116, which is suitably fastened in a part of the casing or coupllng 6, preferably by means of screw-threaded connections.

The valve passages through which operating fluid passes to and from the cylinders may be best described in connection with the operation of the mechanism, which will now be described.

When the elevator door or doors are to be opened from the closed position, illustrated in Figs. 1, 3 and 7, the operating handle connected to the rod 74 is turned by means of which the lower end of the link is moved to the left into the position shown in Fig. 2. By this movement, the upper portion of the lever 70 is swung to the right, by means of which the latch 76 is lifted so as to be disengaged from the holding means 82, and by which the link 68 is also moved to the right, putting the spring 84, connected to the end of the member 68, in=tension. By the opening movement of the operating handle, the

link a'rm66, connected to the link 68,. is

I turned to the right or in a clockwise direction, Fig. 1, by means of which the valve 58 will be swung in a counter clockwise direction from the positions shown in Fig. 4 of the drawings to a position in which the prespassage 62 in the valve 58 with the admission port 120 leading to the end of the cylinder 4, and the exhaust pipe 52 communicates through the passage 60 in the valve 58 with the exhaust pipe 38, communicating with the exhaust port 36 at the end of the cylinder 2. Pressure fluid acting on the piston 30 in the cylinder 4 moves the piston and piston rod 26 to thefi-righflby means of which the guide rod 12, which is connected to the piston rod 26 through the transverse member 18, moves to the right, and the roller 112 moves out of the depression 114. The valve 108 is raised with the movement of the roller away from its seat 122, by means of which the passage 106 communicates through the opening at the seat 122 with the interior of the cylinder a casing 2. As the valve 58 is now in the posi- .58 is in a position to the right of that shown in Fig. 4, in which the passage 106 is cut off from communication therewith. During the movement of the piston 30 in the cylinder 4 to the right, air or other pressure fluid to the right of the piston may be exhausted into the atmosphere through the clearance between the piston rod 26 and the opening in the cylinder head 22. In the cylinder casing 2, during the movement of the piston 28 to the right, the air or pressure fluid in the cylinder at the right of the piston is compressed and at the end of the stroke serves to cushion the movement of the piston and the elevator door mechanism. When the pressure of the cushioning fluid, during the compressing action by the piston, exceeds a predetermined amount determined by the set of the spring 100 in'the relief valve 86, the ball 96 will be raised from its seat against the force of the spring}, whereby the pressure fluid passes throug the openings in the valve and exhausts to the atmosphere, until the pressure is reduced to that determined by the set of the spring 100. By this means a sudden peak or excess of pressure is released, and the rebounding or vibration of the ele- .sure fluid pipe 56 communicates-through the vator door or doors due to the sudden back pressure is entirely overcome, thereby at.- taining smooth operation at both rapid and slow speeds.

When it is desired to close the elevator door, the operating handle is released or turned, assisted by the spring 84, so that the valve 58 is brought into the position shown in Fig. 4 of the drawings By this movement of the valve, the passage 120 leading to the cylinder 4 is brought out of communication with the passageway 62 in the valve, and the air pipe or fluid pressure pipe 56 is brought into communication through the passage 62 in the valve with the passageway 106, by

means of which air passes from the pipe 56 through the passageway 62 in the valve and through the passageway 106 into the end of the cylinder 2, the valve 108 being still in a y raised position. By the passage of pressure fluid through the port or opening of the valveseat 122 into the cylinder 2, the piston 28,.

which is now in the end of the cylinder in proximity to the valve casing or coupllng member 6, is forced to-the left until the apparatus is in the position corresponding to the closed position of the elevator door. In the passage of the piston 28 to the left, the air or pressurefluid in the cylinder to the left of the piston is exhausted mainlythrough the space between the opening in the cylinder .head and the piston rod 24, but also through an auxiliary port 124 in the cylinder which communicates with an opening 126 in the casing 8 connected to the end of the cylinder 2. It is apparent that the exhaust through the ports 36 and pipe 38 remains cut off by the valve 58 during closing movement of the elevator door, and the exhaust pipe 52 communicates during the closing movement through the port opening 60 in the valve 58 with the exhaust pipe 46, which permits exhaust through the ports 44 from the cylinder 4 during the return of the piston toward the left of the cylinder until the port 44 is passed by the piston. During the further movement of the piston in the cylinder 4 beyond the port 44, the air in the cylinder is compressed and serves to cushion the piston 30 and the closing movement of the elevator door. If during the closing movement the pressure in the end of the cylinder 4 should be raised too high, caused by the momentum of the door, which would ordinarily result in a rebound or chattering of the door, the relief valve 88 will open to release the excessive pressure and cause a.smooth and continuous closing movement of the door. Should the valve 58 be suddenly turned so as to admit pressure fluid to the cylinder 4 before the end of the return stroke is reached, at a point where the port 36 has been uncovered by the piston, but the port 124 in the cylinder has not been reached, the. pressure in the cylinder will be released by the passage of fluid through the port 36 into the pipe 38, and through the passageway 60 in vention as illustrated in the drawings, it is to be understood that various changes and modifications may be made as may be apparent to those skilled in the art without departing from thespirit or scope of the invention as defined in the claims.-

Having described the invention, what I claim and desire to secure by Letters Patent 1s:

1. In an elevator door-operating mechanism, a cylinder, a piston in the cylinder, means for operatively connecting the mechanism to an elevator door, a valve, a passageway in said valve, a passageway connecting said valve with one end of said cylinder, means for operating said valve to.control communication of said passageway in said valve with said passageway between said valve and said cylinder, a guide rod, a roller adapted to move on said guide rod, a second valve adapted to open an close communication between the first-named valve and said cylinder, means for adjustably connecting said second valve to said roller, a depression in said guide rod adapted to permit transverse movement of said roller to seat said' second valve, whereby communication between said pressure fluid and said cylinder (vivill be cut oil in the closed position of said oor.

2. In an elevator door operating mechanism, a cylinder, a piston in the cylinder, means for operatively connecting the mechanism to an elevator door, a valve having admission and exhaust passageways therein, means for connecting said valve with a source of pressure fluid supply, a pressure conduit connecting said valve with said cylinder, means for connecting said valve to an exhaust conduit connecting the end of ,said cylinder with said valve, means for operating said valve to alternatively connect and disconnect said conduits with said source of pressure fluid supply and said exhaust, a valve in said pressure conduit, spring means for holding the last-named valve in closed position when said door is closed, and cam means operatively connected to said door whereby the last-named valve will be opened when said door is opened.

3. In an elevatordoor operating mechanism, a cylinder, a piston in said cylinder,

pressing air in the second cylinder during the opening movement of said door to cushion the movements thereof, means for exhausting air from said second cylinder when the pressure therein during the cushioning action exceeds a predetermined amount, thereby preventing jar and rebound of the door during the opening movement thereof, means for cutting off the supply of pressure fluid to said first cylinder, means for admitting pressure fluid to said second cylinder to operate the piston therein and thereby close said door, means for simultaneously exhausting air from the first cylinder during a portion of the stroke, and means for thereafter compressing air to cushion the movements of said mechanism during the closing movement of said door, and means for relieving excess pressure during the cushioning action in the closing movement of said door, whereby a smooth operation of said door is attained.

4. In an elevator door operating mechanism, a cylinder, a piston in said cylinder, means for operatively connecting the said mechanism to an elevator door, a second cylinder, a piston in said second cylinder, means for operatively connecting the piston of the first cylinder with thepiston of the second cylinder, means for admitting air to the first cylinder to open said elevator door, means for compressing air in the second cylinder during the opening movement of said door to cushion the movements thereof, means for exhausting air from said second cylinder when the pressure therein during the cushioning action exceeds a predetermined amount, thereby preventing jar and rebound of the door during the opening movement thereof, means for cutting off the supply of pressure fluid to said first cylinder, means for admitting pressure fluid to said second cylinder to operate the piston therein, and thereby close said door, means for simultaneously exhausting air from the first cylinder during a portion of the stroke, means for thereafter compressing air to cushion the movements of said mechanism during the closing movement of said door, means for relieving excess pressure during the cushioning action in the closing movement of said door whereby a smooth operation of said door is attained, and means for automatically cutting off communication between said ressure fluid supply and said second cylinder when said door is closed, thereby preventing leakage of pressure fluid through the said second cylinder when said door is in closed position. i

5. In an elevator door operating mechanism, a door-opening piston cylinder unit, a door-closingpiston cylinder unit, a valve block having fluid pressure passages connecting said units, a valve in said valve block adapted for manual control, a passageway in said valve communicating with a pressure fluid supply to operate said units, passageways in said valve block communicating with said piston-cylinder units, means for alternately connecting said passageways with the passageway in said valve communicating with said pressure fluid supply, exhaust ports in said piston cylinder units, passageways from said exhaust ports to said valve, a passageway in said valve communicating with the atmosphere, said passageways and said valve being so positioned that when pressure fluidis admitted to said door opening cylinder unit the exhaust passageway in said valve will be in communication with the exhaust passageway from said door closing unit, and when the admission passageway is in communication with said door closing unit, said exhaust passageway is in communication with the exhaust passageway from the said door opening unit, and means, in the passageway for conducting pressure fluid to said door closing unit, for cutting off communication of pressure fluid therewith when said door is in closed position, whereby leakage from said unit is prevented in closed position of the door.

Signed at New York city, New York, this 13th day of November, 1923.

WILLIAM WALLACE WEEKS.

US674848A 1923-11-15 1923-11-15 Elevator door operating mechanism Expired - Lifetime US1807231A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US674848A US1807231A (en) 1923-11-15 1923-11-15 Elevator door operating mechanism

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US674848A US1807231A (en) 1923-11-15 1923-11-15 Elevator door operating mechanism

Publications (1)

Publication Number Publication Date
US1807231A true US1807231A (en) 1931-05-26

Family

ID=24708127

Family Applications (1)

Application Number Title Priority Date Filing Date
US674848A Expired - Lifetime US1807231A (en) 1923-11-15 1923-11-15 Elevator door operating mechanism

Country Status (1)

Country Link
US (1) US1807231A (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2448459A (en) * 1943-11-01 1948-08-31 Stewart Warner Corp Piston actuated air motor valve mechanism
US2502487A (en) * 1946-03-14 1950-04-04 Scholl James Edward Decelerator for catapult pistons
US2622564A (en) * 1948-02-24 1952-12-23 Nordberg Manufacturing Co Servomotor and a throttling means for its fluid supply
US2783742A (en) * 1954-11-22 1957-03-05 Shafer Valve Co Automatic pressure reducing means for hydraulic gate valve operator
US2786452A (en) * 1954-11-29 1957-03-26 Hannifin Corp Fluid actuated cylinder having fluid cushion means
US2794423A (en) * 1955-10-10 1957-06-04 Power Brake Equipment Company Remote positioning system
US2855899A (en) * 1956-05-02 1958-10-14 Ben J Beaty Device for controlling insertion of rod
US2954052A (en) * 1959-02-19 1960-09-27 Cessna Aircraft Co Pressure fluid control system and valve
US2989303A (en) * 1958-10-13 1961-06-20 Mercier Jean Actuating mechanism for sliding members
US3033233A (en) * 1959-07-03 1962-05-08 Cessna Aircraft Co Anti-cavitation control system and valve
US4476678A (en) * 1980-01-31 1984-10-16 Plc Peters Limited Control mechanism for pneumatic apparatus

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2448459A (en) * 1943-11-01 1948-08-31 Stewart Warner Corp Piston actuated air motor valve mechanism
US2502487A (en) * 1946-03-14 1950-04-04 Scholl James Edward Decelerator for catapult pistons
US2622564A (en) * 1948-02-24 1952-12-23 Nordberg Manufacturing Co Servomotor and a throttling means for its fluid supply
US2783742A (en) * 1954-11-22 1957-03-05 Shafer Valve Co Automatic pressure reducing means for hydraulic gate valve operator
US2786452A (en) * 1954-11-29 1957-03-26 Hannifin Corp Fluid actuated cylinder having fluid cushion means
US2794423A (en) * 1955-10-10 1957-06-04 Power Brake Equipment Company Remote positioning system
US2855899A (en) * 1956-05-02 1958-10-14 Ben J Beaty Device for controlling insertion of rod
US2989303A (en) * 1958-10-13 1961-06-20 Mercier Jean Actuating mechanism for sliding members
US2954052A (en) * 1959-02-19 1960-09-27 Cessna Aircraft Co Pressure fluid control system and valve
US3033233A (en) * 1959-07-03 1962-05-08 Cessna Aircraft Co Anti-cavitation control system and valve
US4476678A (en) * 1980-01-31 1984-10-16 Plc Peters Limited Control mechanism for pneumatic apparatus

Similar Documents

Publication Publication Date Title
KR20060134221A (en) Valve actuation system with valve seating control
US2113161A (en) Riveting apparatus
US2827766A (en) Hydro-pneumatic press apparatus
US2415462A (en) Ceramic molding press
US2490823A (en) Hydraulic-pneumatic system
US2369505A (en) Remote-control valve
US2355520A (en) Compression riveter
US2301099A (en) Control mechanism
US2027423A (en) Doorcheck
US2061120A (en) Steering mechanism
US2338157A (en) Controlling device
US899795A (en) Fluid-pressure motor.
US1007792A (en) Press.
US2310625A (en) Compression riveter
US967565A (en) Furnace-door opener.
US931228A (en) Valve.
US791075A (en) Pneumatic attachment for riveting and plate-closing machines.
US1745549A (en) Die cushion
US1885235A (en) Follow-up actuating mechanism for pressing machines
US2355692A (en) Throttle valve mechanism
US2013102A (en) Garment or ironing press
US1849691A (en) Sheet metal press
US2398811A (en) Controlling valve for hydraulic motors
US2055815A (en) Motor for pressing machines and the like
US1692034A (en) Door engine