US3161074A

US3161074A - Electromotive adjusting device

Info

Publication number: US3161074A
Application number: US257271A
Authority: US
Inventors: Korthaus Helmut; Wilke Richard
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-02-14
Filing date: 1963-02-08
Publication date: 1964-12-15
Anticipated expiration: 1981-12-15
Also published as: BE628339A; SE315778B; GB1027600A; DE1190759B

Abstract

1,027,600. Screw - and - nut actuators. H. KORTHAUS, and R. WILKE. Feb. 13, 1963 [Feb. 14, 1962], No. 5915/63. Heading B8J. [Also in Divisions F2 and H2] In an electric motor-driven linear displacing device comprising an internally threaded tubular shaft section 8 fast with the motor rotor 4 and a coacting elongated threaded operating rod 12 extending through the shaft section and secured against rotation but axially displaceable on rotation of the shaft section, and an electromagnetically operable brake for the rotor actuated when the rod reaches a limiting position, either a load or at least one spring 32, 33 returns the rod to its initial position upon failure of the motor and brake current. The rod 12 is secured against rotation by either a polygonal, e.g. square, part engaging a corresponding guide in a casing extension 15 or a longitudinal recess engaged by a key in a casing part 14, and coacts with the shaft section by means of a train of recirculating ball bearings 11. The brake includes friction linings 28 loaded to disengagement by springs 27 but engaged by attraction of a disc 25 by an iron ring 18 when a magnetizing winding 17 is energized via a rectifier by normally closed contacts of a motor relay which is de-energized by a limit switch 30 or 31 actuated by a cam 29 on a rod collar 34 when the rod reaches either of its end positions. In low power motors the switches may directly control the motor, and the rod may actuate the sliding contact of a potentiometer to give a remote indication and possibly automatic regulation of the rod position. The device is applicable to doors, flaps and weights.

Description

Dec. 15, 1964 H. KORTHAUS ETAL 3,

ELECTROMOTIVE ADJUSTING DEVICE Mrnvroxai $6 5 [$41M Filed Feb. 8, 1963 United States Patent Ofitice 3,151,074 Patented Dec. 15:, 1964 3,161,(l74 ELECTROMQTKVE ADJUSTING DEVIGE Helmut Korthaus, Fernbliclr 3, Wuppertal-Barmen, Germany, and Richard Willie, Eschfeldstr. 11, Gelsenkirchen-Bner, Germany I t lled Feb. 8, 1963, Ser. No. 257,271 Claims priority, application Germany, Feb. 14, 1962, K 45,889 7 Claims. (G. 74-4246) The present invention relates to an electromotive adjusting device, for instance, for doors, shutting flaps and for any other mechanism to be adjusted, whereby the rotary movement of the rotor is transformed into an axial reciprocating movement of an operating rod and furthermore, wherein this device is equipped with a magnet brake, as well as with means fora return of the operating rod into a safety position upon discontinuance of feeding of energy.

In adjusting devices of the type set forth above, it is a requirement that in case of danger, thus, for instance, also upon loss of the operating energy, the adjusted device returns automatically into its safety position. Thus, for instance, a weataher door in a mine, must be capable of performing an automatic opening or also closing, if the mine ventilator becomes inoperative, or a brake must be applied, if the driving energy for a machine ceases, or even the doors of a bank should close automatically, if electric current feed discontinues.

In all above-stated cases, in which the operating device for these purposes is controlled by means of pressurized air or by means of pressurized oil or by means of another fluid, that means, by the use of cylinders and pistons reciprocating therein, the automatic return into its safety position results by itself, since upon loss of the pressure lof the driving air or fluid, the piston is freed for a return stroke.

Furthermore electromagnetically effective operating devices are also known, which likewise release the operating mechanism upon ceasing of current feed, so that it closes. Since, however, as is well known, the pulling force of a magnet on an iron armature decreases rapidly with increasing distance between these two members, only short lifting strokes are'possible to be performed by the magnetic force. The sudden pull and release of the armature is also a disadvantage.

It is, therefore, one object of the present invention to provide an electrically driven operating device for the described applications, which operates purely electrically without the use of an intermediate medium, as pressurized air or pressurized oil, and without requirement for the otherwise necessary compressors, without having the disadvantages of the electromagnetically effective operating devices.

It is another object of the present invention to provide an electrically operating adjusting device, wherein a hollow shaft section is flanged to at least one end, preferably, however, to both ends of a rotor, which hollow shaft section extends axially within a motor housing and is mounted in the latter, whereby one of the two hollow shaft sections is formed for parts of its axial length as a nut receiving balls of a ball-thread having low friction, which nut provides a bearing for an operating rod which is formed for at least a part of its axial length as a ballthread spindle and which projects freely through the rotor, as well as through the oppositely disposed hollow shaft sections, and which operating rod is locked against rotation and cooperates with return setting means which operate either with a pulling or pushing force at the opposite end.

It is still another object of the present invention to provide an electrically operating adjusting device, wherein an electromagnetic brake is provided surrounding the section of the hollow shaft which is free of the ball-thread, a brake ring of. the electromagnetic braking covered with brake material cooperating with a ring flange of the hollow shaft section extending in radial direction and covered likewise with braking material, and thus effects the rotor and the ball-thread spindle.

The rotary locking of the ball-thread spindle can be brought about, for instance, in such manner that the opposite end of the spindle is formed with a polygon crosssection and is mounted in a corresponding guide of a motor housing extension formed'as a protecting cap, or

that the portion of the spindle having circular. cross-section V cooperates with a feather-like guide key, which is prowithin the range of the' vided for this spindle portion motor housing passage.

It is also another object of the present invention to provide an electromotive adjusting device, wherein for the return of the device and of the ball-thread spindle, respectively, in case of danger, return springs are provided in form of pressure springs and/ or tension springs, which are suitably disposed within the protecting cap and which engage, on the one hand, a common collar of the spindle and on the other hand, the motor housing, as well as the end wall of the protecting cap.

The fact that additionally the switch contacts are disposed in the protecting cap which switch contacts cooperate with a switching cam of the spindle, are particular structural advantages of the present invention.

It now in a device, designed in accordance with the present invention, a danger occurs, that means, if the current fails, for instance, at the moment, in which the operating rod just opens the flap at the exit of a bunker, then, on the one hand, the motor loses its current and, on the other hand, the magnet brake opens up, so that in the present instance, return means formed as springs can be rendered effective, and move back the operating rod in axial direction, until the safety condition, that means, the original position, is assumed, and thus, the flap is closed again. The friction of the ball-thread is so low thereby, that a return setting is possible without any diificulties.

Summarizing, it can be stated that the present invention provides, by using structurally simple means, a particw larly advantageous and economic adjusting apparatus, which even in the case of danger, for instance, in case of loss of current feed, is in position to return automatically to its original position, whereby the requirements of the practice are taken in account to the full extent.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawing, in which the only figure is an axial section of an adjusting device.

Referring now to the drawing, the adjusting device comprises a housing 1, in which an electric motor with a stator winding 2 and a stator 3 is disposed, which electric motor starts rotation of the rotor 4 upon connection with the current source. The motor can be a three phase current motor, an alternating current motor, an A.C./D.C.motor or a direct-current motor, for which reason, also for the different structural possibilities the brushes 5 and the collector 6 areshown. These parts can be omitted in case of a three-phase motor.

The rotor 4 has longitudinal bores distributed about its periphery, through which two flanged hollow shaft sections 8 and 9 are rigidly and concentrically connected by means of screw-bolts 7. The sections 8 and 9 serve also the purpose of centering the inside of the shortcircuiting ring It worked to exact measurements and disposed on both sides of the rotor 4. The hollow shaft section 8 includes a ball-thread, which has an appreciably smaller friction compared with a normalthread, because the threads are replaced by balls 11 rolling during the relative movement of the nut and the thread. The threads of the operating rod 12 having circular crosssection form the other part of the ballthread, which operating rod 12 has a forked head 13 at its upper end. As much as this connection does not permit a rotation of the operating rod 12, the latter will reciprocate axially in either direction upon switching on the motor in dependency upon its direction of rotation.

It is possible, however, also that the operating rod 12 be equipped with a longitudinal groove (not shown) over a wedge guide, which is arranged, for instance, in the washer member 14, and which prevents the rotation and, thereby, brings about the reciprocating movement of the operating rod 12. It is also possible to form the lower end of the operating rod 12 in the housing or protecting cap 15 with a square cross-section, and to arrange a corresponding guide in the housing 15, in order to bring about the same effect, whereby it has been found of advantage, that the outwardly projecting operating rod 12, due to the elimination of the longitudinal groove, can be more easily sealed relative to the housing 1 at the point of the washer member 14, in order to prevent the penetration of dirt into the housing 1. The operating rod 12 is guided only in the ball-thread and can freely reciprocate otherwise, if the guiding by a guide wedge, or by a square cross-section of one end, is neglected, which operating rod 12, however, may be also designed for easy operation.

On the other side of the rotor 4 the hollow shaft section 9, having a radially extending flange 13, serves as a brake-disk of a magnet brake. The magnet brake comprises, as is known, a field coil 17 disposed in an iron ring 18, which is rigidly secured in the motor housing 1. The iron ring 18 receives inside thereof a roller bearing 19, in the same manner as on the opposite side a housing part or an annular member 20 connected with the housing 1 receives the roller bearing 21. These two roller bearings 19 and 21 thus constitute the actual mounting of the motor. The two

thrust bearings

22 and 23 serve the purpose of absorbing the sliding pressure 'of the operating rod 12 upon the housing 1 and finally, its displacement (not shown).

Two

annular disks

24 and 25 are disposed on the front and back side, respectively, of the annular magnet 18 with its field coil 1'7, which

annular disks

24 and 25 are connected by means of bolts 26 distributed equally about the periphery. A pressure spring 27 is arranged on each of the bolts 26, which pressure spring 27, supporting itself in its inoperative position on the bottom of the iron ring 18, retains the two connected

annular disks

24 and 25 in the position shown in the drawing. The brake, formed of the parts 16 and the annular disk 24 with the two brake coverings 28, is thus open or in its inoperative position. The part 16 can rotate freely and the operating rod 12 moves in one direction depending upon the direction of rotation as long, till the collar cam 29 either engages the contact 30 or the contact 31, both of the cont-acts 30 and 31 being likewise disposed in the housing part 15, which contacts 30 or 31 interrupt the feeding of current to the motor through the circuit breaker of the motor. At the same moment, the annular field coil 71 is connected with the phase voltage of the motor by means of the closing contacts of the circuit breaker With the help of a rectifier. The magnet pulls the disk 25 at its front side and brings into engagement, thereby, the brake coverings 28, so that the operating rod 12 is likewise secured in its position by means of the retained rotor and the ball-thread.

A load which, for instance, has been lifted by means mum torque of the motor, which is required for the lifting of the load.

It is quite apparent that upon changing the polarity of the motor and reinstatement of the circuit breaker, the magnet loses its power, the motor runs in opposite direction and the load is, for instance, lowered, until the engagement with the corresponding contact, either 30 or 31, is brought about. It is also possible, to lower the lifted load without changing the polarity of the motor, by switching off instead the current from the magnet 18, whereupon the brake is rendered inoperative and the lowering load turns the rotor which is not under current feed, since the ball-thread, due to its very low friction losses, transforms the force of the load effective in longitudinal direction of the operating rod 12 with only very little energy loss by means of the ballthread into a rotary motion and consumes itself in the acceleration work for the rotor 4.

It is particularly clear from the arrangement set forth above, that the actual purpose of the present invention is achieved because, in case of loss of electrical energy feeding, the electromagnet 18 is rendered inoperative and the brake 28 opens by means of the springs 27, so that, thus, for instance, the lifted load returns into its original position. In the cases, in which the load has to be moved not vertically, but horizontally, and in cases in which practically no load has to be moved, rather only a displacement of very small masses takes place, the return of the operating rod 12 into its original and resting position, respectively, or safety position is brought about by means of the

springs

32 or 33. These springs of which only one may be provided, depending upon the intended effect, pull or push upon complete loss of current the operating rod 12 into the resting or original position, due to the opening brake 28, because, as stated above, the ball-thread has no friction of any significance.

A very suitable and useable application range for this embodiment .is found, for instance, in the automatic operation of the hand brake of automotive vehicles. It is possible, without any particular additional circuits, to connect the motor of the device, designed in accordance with the present invention, to the battery of the vehicle by means of the ignition key, such that upon switched-on ignition, the hand brake is released. In this case, the motor has been put to rotation by the battery voltage, until it is switched off by the terminal contacts and the magnet brake is switched on at the same moment, which retains the operating rod 12 in the opening position for the hand brake. If the vehicle is put out of operation, in which case the ignition is switched off, the magnet loses likewise its power and the operating rod 12 is pulled by one of the

springs

32 or 33 required therefor into the vehicle brake, whereby automatically a safety of the nonmoving vehicle is brought about. For this device there is, thus, neither an additional hydraulic, nor a pneumatic energy production and operating device required, rather merely the already present vehicle battery is necessary.

Instead of switching off the motor by means of the contacts 30 and 31 over a circuit breaker, it is also possible, particularly with a small motor output, to use these contacts 30 and 31, for instance, as a micro-switch of high switching output directly for the switching-otf, as well as for switching-on the motor. By this arrangement a small spatial structure of the total device is achieved, which is also suitable for the operation of locks on doors. In general, the field of application are manifold, since ball-threads are made already with smallest measurements. It is also conceivable, to provide potentiometers in the housing 15 in addition to the contacts 30 and 31 such, that the position of the operating rod 12 makes possible a remote indication by means of a brush contact secured thereto and even an automatic control of a desired intermediate position of the operating rod 12, so that it is possible in this manner, to control, for instance, the brake pressure at a constant predetermined value and also other possibilities exist. Instead of providing a combination of a normal motor and a magnet brake, a special motor can he used, which permits the remaining in power even with a load, similarly to a motor for rollers, so that the magnet brake is superfluous, since in case of loss of the current feeding, then the lifted and by the motor retained load can likewise be lowered.

It is also understood that the shown and described embodiment constitutes merely an example for the realization of the present invention and should by no means be limited thereto, rather some other embodiments and applications can be realized Within the scope of the present invention. This relates in particular to a varied structural formation.

While we have disclosed one embodiment of the present invention, it is to be understood that these embodiments are given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

We claim:

1. An electromotive adjusting device comprising a housing,

an electric motor including a rotor,

an operating rod non-rotatably extending axially through said rotor and reciprocating in axial direction within said rotor and having a ball receiving thread for a part of its length,

a magnet brake disposed axially spaced apart from said rotor,

at least one hollow shaft section having a flange disposed axially adjacent said rotor and mounted in said housing,

said hollow shaft section including along a part of its axial length a nut complementary to said ball receiving thread of said operating rod and receiving balls, said nut supporting said operating rod,

means disposed at one end of said opertaing rod for returning the latter to its orig nal position, and means securing said hollow shaft to said rotor.

2. The device, as set forth in claim 1, wherein said magnet brake surrounds at least one of said hollow shaft sections,

said one of said hollow shaft sections having a radially disposed flange carrying a layer of braking material on one of its faces,

said electro-Inagnetic brake including a brake ring carrying a layer of braking material opposite said layer of said flange,

said brake ring cooperating with said flange and thus stopping the rotation of said one of said hollow shaft sections and, thereby, of said rotor.

3. The device, as set forth in claim 1, which includes a protecting cap extending from one end of said operating rod extending beyond said housing into said protecting cap.

4. The device, as set forth in claim 3, which includes a longitudinal potentiometer disposed in said protecting cap adjacent the end of said operating rod, and

the latter having a sliding contact engaging said potentiometer during the axial movement of said operating rod. 5. The device, as set forth in claim 3, which includes tension and pressure springs, respectively, disposed within said protecting cap and affecting the end of said operating rod guided in said protecting cap, and

said tension and pressure springs causing a reciproeating movement of said operating rod into its original position during non-operativeness of said magnet brake and during non-feeding of said electric motor.

6. The device, as set forth in claim 5, wherein said operating rod has a collar at its end projecting from said housing, and

said springs comprise a first spring engaging said housing at one of its ends and said collar at the other of its ends, and

a second spring engaging the outer end Wall of said protecting cap at one of its ends and said collar at the other of its ends.

7. The device, as set forth in claim 6, wherein said protecting cap has switching contacts axially spaced apart from each other, and

a cam disposed on said collar and engaging said switching contacts in corresponding axially spaced apart positions of said operating rod.

References Cited by the Examiner UNITED STATES PATENTS 2,383,901 8/45 Werner 74-4248 X 2,406,156 8/46 Nardone 192-2 X 2,918,827 12/59 Brown 74-4248 2,956,188 10/60 White 74-4248 X DON A. WAITE, Primary Examiner.

Claims

1. AN ELECTROMOTIVE ADJUSTING DEVICE COMPRISING A HOUSING, AN ELECTRIC MOTOR INCLUDING A ROTOR, AN OPERATING ROD NON-ROTATABLY EXTENDING AXIALLY THROUGH SAID ROTOR AND RECIPROCATING IN AXIAL DIRECTION WITHIN SAID ROTOR AND HAVING A BALL RECEIVING THREAD FOR A PART OF ITS LENGTH, A MAGNET BRAKE DISPOSED AXIALLY SPACED APART FROM SAID ROTOR, AT LEAST ONE HOLLOW SHAFT SECTION HAVING A FLANGE DISPOSED AXIALLY ADJACENT SAID ROTOR AND MOUNTED IN SAID HOUSING SAID HOLLOW SHAFT SECTION INCLUDING ALONG A PART OF ITS AXIAL LENGTH A NUT COMPLEMENTARY TO SAID BALL RECEIVING THREAD OF SAID OPERATING ROD AND RECEIVING BALLS, SAID NUT SUPPORTING SAID OPERATING ROD, MEANS DISPOSED AT ONE END OF SAID OPERATING ROD FOR RETURNING THE LATTER TO ITS ORIGINAL POSITION, AND MEANS SECURING SAID HOLLOW SHAFT TO SAID ROTOR.