US3424058A

US3424058A - Torque responsive linear actuator

Info

Publication number: US3424058A
Application number: US535844A
Authority: US
Inventors: Baron C Wolfe
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-03-21
Filing date: 1966-03-21
Publication date: 1969-01-28
Anticipated expiration: 1986-01-28

Description

Jan. 28, 1969 B. c. WOLFE 3,424,058

TORQUE RESPONSIVE LINEAR ACTUATOR I Filed March 21, 1966 Sheet of 2 (@(mmp r t 5: Qfl \2 if A i I 2 a B I \V IG. I v I v I 9 l6 I 4 I 2o 52 :18:- 0

:54 I 5 58 +3 46 4 INVENTOR.

44 BY BARON o, WOLFE FIG. 2 l w'as-r.ml lnmwnsuu) Jan. 28, 1969 A BC. WOLFE 3,424,058

TORQUE RESPONSIVE LINEAR ACTUATOR Filed March 21,

Sheet INVENTOR.

BA R0; 0. WOLFE BY mama-J amm su l ATTORNE YS United States Patent 3,424,058 TORQUE RESPONSIVE LINEAR ACTUATOR Baron C. Wolfe, 24 W. Grant St, Eureka, Calif. 95501 Filed Mar. 21, 1966, Ser. No. 535,844 US. Cl. 91-105 Int. Cl. F01c 1/00; F1611 29/20 2 Claims ABSTRACT OF THE DISCLOSURE This invention relates to apparatus for controllably positioning and driving a load along a linear path in response to rotation of a hydraulically operated actuator.

Although the present invention is described hereinafter by way of example in connection with a Weir gate, the invention has utility in any application requiring adjustable positioning of a load along a linear path. Apparatus constructed according to the present invention can be adapted to opening and closing sliding doors,"moving aircraft control surfaces, such as ailerons, positioning and feeding cutting tools on machines, and virtually any environment in which it is desired to move or position a load along a linear path.

As shown more fully hereinafter in connection with a weir gates, the invention includes a threaded shaft secured to a load such as a weir gate, an interiorly threaded sleeve circumscribing the shaft, and a rotary hydraulic actuator for rotatively driving the sleeve. A complete description of a rotary hydraulic actuator is disclosed in my U.S. Patent No. 3,241,456. Such patent discloses an actuator that has a cylindric chamber and a lobed rrotor mounted within the chamber concentrically thereof. Within the chamber is provided a plurality of sliding vanes that bear against the peripheral surface of the rotor to define various power compartments. Fluid passages are provided in the actuator for controllably delivering pressurized hydraulic fluid to the compartments to rotatively drive the rotor. The sleeve is mounted concentrically of the rotor so that on application of pressurized hydraulic fluid to the device, the sleeve is rotatively driven so as to position the shaft and the load along a linear path.

An object of the invention is to provide a remotely controllable linear actuator that can accurately and continuously position a load along a path. This object is achieved by providing a hydraulic rotary actuator that is capable of delivering high torque in either a forward or reverse direction of rotation and by threadedly coupling to such actuator a shaft to the end of which a load is attached.

A feature and advantage of this invention is that the force applied to the load is uniform throughout the entire range of movement. A consequence of such uniform force is that the load can be accurately positioned at any desired point along its path of movement.

Another feature and advantage of this invention is that extremely heavy loads can be adjustably positioned. As more fully disclosed in the aforecited patent, the rotary hydraulic actuator is capable of delivering extremely high torque. By converting such torque to linear motion 3,424,058 Patented Jan. 28, 1969 "ice the present invention permits linear positioning of large loads.

Still another feature and advantage is that close positional control of a load can be effected by a device constructed according to the invention. The rotary actuator, because of its symmetrical design, is capable of rotation in either direction. Moreover, the actuator delivers high torque at low rotative speeds. Such desirable characteristics are preserved in converting the rotary force to a linear force, as a consequence of which the position of the load can be established with a high degree of precision.

Yet another feature and advantage of this invention is that the apparatus is extremely compact, a characteristic rendering the apparatus particularly suitable for such applications as actuating aircraft control surfaces.

A further feature and advantage is that the load, once moved to a desired position, is retained in such position without braking or application of power until further movement of the load is desired.

Other objects, features and advantages will be more apparent on referring to the following specification and accompanying drawings in which:

FIG. 1 is a perspective view of the actuator of the present invention as employed in controllably positioning a weir gate;

FIG. 2 is a cross-sectional view of the actuator taken substantially along line 2-2 of FIG. 3; and

FIG. 3 is an elevation view of the actuator, portions being broken away along line 33 of FIG. 2 to reveal internal details of construction.

Referring more particularly to the drawings, reference numeral 12 indicates a threaded shaft carried in a rotary actuator generally indicated at 14 for movement along a path co-extensive with the longitudinal axis of the threaded shaft. In FIG. 1, the lower end of shaft 12 is shown attached to a gate A that is vertically slidable in grooves B that confront one another across an opening in a weir C. The linear actuator of this invention acts to vertically position gate A in proportion to the amount of water that it is desired to pass through the opening in weir C.

Rotary actuator 14 includes a casing 16 having an internal cylindric surface 18 defining a cylindric chamber. Exterior of the cylindric chamber, casing 16 is provided with suitable mounting brackets 20 for fixing the chamber relative to the load. The cylindric chamber is completed by end plates 22 secured to casing 16 by any suitable expedient, such as screws 24. Rigid with each end plate 22 and preferably integral therewith is a hub 26 which is bored concentrically of cylindric surface 18 to rotatively support or journal a sleeve 28. Suitable thrust bearings 30 are provided to prevent axial movement of sleeve 28 relative casing 16, such thrust bearings being shown somewhat schematically in FIG. 3 since they are conventional elements.

Mounted on sleeve 28 interior of cylindric surface 18 is a rotor 32 constituted by a body having a plurality of lobes 34 radiating therefrom in uniform spaced relation around the periphery of the rotor. The peripheral extremities of lobes 34 are formed concentrically of the axis of cylindric surface 18 and cooperate with the cylindric surface in a non-contacting fluid-sealing relation. A noncontacting fluid-sealing relation, as more fully described in the aforecited patent, is a relation frequently employed in the hydraulic arts wherein the peripheral surface of the lobe does not contact the cylindric surface but is sufiiciently close to prevent hydraulic fluid from passing from one side of the lobe to the other side. A clearance of approximately .0005 inch affords such relationship. The side surfaces 36 of rotor 32 bear a similar relationship to the inner faces 38 of end plates 22; such relationship is exaggerated in FIG. 3 for clarity. Sleeve 28 and rotor 32 are joined for rotation in unison by any suitable expedient, such as a key 40.

Although rotor 32 is shown herein as including three lobes 34 such showing is only exemplary, because as shown in the aforecited patent, a body having a greater number of lobes can be used. Casing 16 defines a plurality of radially extending slots 42 which are uniformly spaced around the periphery of the casing and which slidably support vanes 44. The number of slots 42 and vanes 44 exceeds the number of lobes on rotor 32, there being four slots and vanes in the embodiment herein described. For convenience of description each vane 44 will be considered as having a clockwise face 46 and a counterclockwise face 48. Each vane is biased into contact with the peripheral surface of rotor 32 by a compression spring 50 so that, as can be seen most clearly in FIG. 2, a plurality of compartments 52 are defined by cylindric surface 18, the peripheral surface of rotor 32 and clockwise face 46 of the vane. Corresponding compartments 54 are defined by cylindric surface 18, the peripheral surface of rotor 32 and counterclockwise vane face 48.

Communication of hydrauli fluid to and from compartments 52 and 54 is established by

respective conduits

56 and 58 formed in each vane. Circumferentially extending channels 60 and 62 are provided for communicating hydraulic fluid to

respective conduits

56 and 58,

fittings

60F and 62F being provided for connection of hydraulic lines 64. A conventional hydraulic pressure source, not shown, is provided 'for selectively supplying hydraulic fluid to one of lines 64 and discharging the fluid from the other line 64. The particular direction of fluid flow determines the direction of rotation of rotor 32 which in turn determines the direction of lineal movement of shaft 12.

In operation, when it is desired to raise gate A for example, hydraulic fluid under pressure is applied to the line 64 that communicates with conduit 56 and compartments 52. Hydraulic fluid is exhausted from conduits 58 which communicate with compartments 54. Such pattern of fluid flow causes rotor 32 and sleeve 28 to rotate clockwise. Consequently, shaft 12 moves upwardly and opens weir gate A. The connection between the lower end of shaft 12 and weir gate A prevents rotation of the shaft, which is essential to effecting linear movement. Should it be desired to drive a load that is not constrained against rotation as is weir gate A, it will be obvious that a longitudinally extending groove can be formed in shaft 12 and that a key or like member can be firmly affixed to casing 16 which key slides in the slot to prevent the shaft from rotating with sleeve 28.

When it is desired to lower weir gate A or like load, hydraulic fluid is applied to the opposite fluid line 64 so that hydraulic fluid under pressure flows through conduit 58 into compartments 54, thereby to drive rotor 32 in an opposite or counterclockwise direction as viewed in FIG. 2.

It will be obvious that the position of weir gate A once it is established will be maintained without necessity for applying hydraulic fluid to the apparatus, because of the pitch of the threaded engagement between shaft 12 and sleeve 28. Consequently, when it is desired to move the load along a linear path, the apparatus is energized from a quiescent state by application of hydraulic pressure to one or the other of fluid lines 64. Since lobed rotor 32 has fewer lobes than there are vanes 48 at least one compartment 52 and/or 54 will at all times be in a proper phase for application of torque to sleeve 28 in response to pressurized fluid supplied to the compartment. Consequently, close positional control of the load secured to shaft 12 can be effected; the precision of control possible with the present apparatus is limited only by the conventional apparatus provided for controllably applying the hydraulic fluid to lines 64.

As described in my Patent No. 3,241,456, rotary actuator 14 can be made virtually any size so that loads of virtually any size can be accurately positioned by use of the present apparatus. Obviously the showing in the drawings of the present invention of shaft 12 aligned in a vertical position is only exemplary; the shaft can be mounted in any position along which linear movement is desired.

Thus it will be seen that the present invention provides an actuator for accurately positioning a load along a linear path which apparatus can be controlled remotely since it utilizes a conventional hydraulic apparatus in energizing the actuator. Moreover, because the size of the actuator can be constructed to almost any desired size, the amount of load and the length of the path over which the load is positionable can be accommodated.

Although one embodiment of the present invention has been shown and described it will be obvious that other adaptations and modifications can be made without departing from the true spirit and scope of the invention.

What is claimed is:

1. Apparatus for positioning a load along a linear path comprising a threated shaft attached to said load and disposed in said path; an interiorly threaded sleeve circumscribing said shaft and threadedly engaged therewith; a hydraulic motor having a rotor in driving connection with said sleeve and a casing defining a cylindric chamber, said rotor being journalled for rotation in said chamber about the cylindric axis thereof, said hydraulic motor including a first plurality of vanes mounted in said casing and extending radially inwardly into contact with the peripheral surface of said rotor, said rotor being formed with a second plurality of lobes radiating outwardly therefrom in uniformly peripherally spaced relation concentric with said casing, said first plurality being greater than said second plurality thereby establishing at least one compartment bounded by the surface of said cylindric chamber, said rotor and a forward face of one said vane, and another compartment bounded by the surface of said cylindric chamber, said rotor and the rear face of one said vane, said chamber having first and second fluid conduits communicating with a respective one of said compartments so that admission of hydraulic fluid under pressure into said one compartment will rotatively drive said rotor in one direction and admission of hydraulic fluid under pressure into said another compartment will rota- References Cited UNITED STATES PATENTS 1,423,817 7/1922 Pitz et al. 74-89.l5 2,400,418 5/1946 Hofbauer 91-420 X 2,748,877 6/1956 Miller et al 9l-420 X 2,919,911 1/1960 Furtah 74-89.15 2,978,129 4/1961 Becker 9l420 X 3,241,456 3/1966 Wolfe 91-105 OTHER REFERENCES Product Engineering, vol. 33, No. 7, Apr. 2, 1962, Rotary to Linear Motion, Ball, R. C., pp. 68-73.

MARTIN P. SCHWADRON, Primary Examiner. IRWIN C. COHEN, Assistant Examiner.

US. Cl. X.R.