US 3619090 A
Description (OCR text may contain errors)
United States Patent  Inventor Heinz Hartkopf Solingen, Germany  Appl. No. 9,785  Filed Feb. 9,1970  Patented Nov. 9, 1971  Assignee Th. Kieserling & Albrecht Werkzeugmaschlnenfabrik Solingen, Germany  Priority Feb. 11, 1969  Germany  Pl906651.4
 APPARATUS FOR REG ULATING THE SPEEDS 0F DRIVEN UNITS IN MACHINE TOOLS OR THE LIKE 10 Claims, 8 Drawing Figs.
 US. Cl 417/426, 74/469, 74/480, 417/429  Int. Cl ..F04b 23/04, F04b 41/06  Field of Search .0 417/425, 426, 429, 222, 427, 428; 137/99; 74/469, 480
 References Cited UNITED STATES PATENTS 3,116,852 1/1964 Anderson 417/429 X Primary ExaminerCarlton R. Croyle Assistant Examiner-Richard J Sher Attorney-Michael S. Striker ABSTRACT: The rate of delivery of two axial piston pumps is adjustable by the cores of two flexible shafts each of which can change the inclination of a pivotable part in the respective pump. The cores carry followers movable in slots provided in the anus of a lever which is pivotable to thereby change the delivery of one or both pumps. The lever can be pivoted by a reciprocable holder having two forks which guide the followers and move them toward or away from the axis of the lever in response to displacement of the holder. This causes adjustment ofone of the pumps because one of the followers is normally held against movement in a direction to move the corresponding core axially. The pumps can be adjusted simultaneously if the one follower is moved by a slide to thereby pivot the lever and cause the other follower to move the corresponding core lengthwise to the extent determined by selected distances between the axis of the lever and the followers.
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IN VENTOR PATENTEUunv 9 ISTI SHEET 6 [1F 7 IN VEN TOR fir/in HA/Ulw r APPARATUS FOR REGULATING THE SPEEDS OF DRIVEN UNITS IN MACHINE TOOLS OR THE LIKE BACKGROUND OF THE INVENTION The present invention relates to apparatus for controlling the operating speeds of driven units in machine tools or the like, particularly for regulating the speeds of advancing and straightening units in a machine for straightening of elongated tubular or bar stock. Still more particularly, the invention relates to improvements in apparatus which can be utilized to effect simultaneous or independent changes in speeds of two or more units in machine tools as well as to select and maintain a desired ratio between such speeds.
Many machine tools comprise several groups of elements which must be driven at difierent speeds and wherein the speed of one group must be synchronized with the speed or speeds of one or more additional groups. For example, a shaving machine for tubes or bars normally comprises a revolving head for one or more cutting tools serving to remove material from the external surface of a workpiece which is fed lengthwise by carriages, rolls or other advancing means. The rotational speed of the head must be synchronized with operating speed of the advancing means but the ratio between the two speeds must be variable if the machine is to be capable of treating workpieces of ditferent diameters and/or if the material of a preceding workpiece is different from the material of the next-following workpiece. The machine should be capable of increasing and reducing the two speeds but the ratio between the two speeds should normally remain the same. In certain presently known shaving machines for tubes or the like, the means for rotating the shaving head and for operating the advancing means comprises a pair of so-called Leonard drives one of which rotates the head and the other of which transmits motion to the advancing means. The two drives are connected to each other by an electrical speedregulating device which insures that the ratio of the speed of shaving head to the speed of advancing means remains unchanged irrespective of changes in r.p.m. of the head. Such speed regulating device is disclosed, for example, in German Pat. No. 1,187,456. A drawback of Leonard drives and of the aforementioned electrical regulating device is thatthey are too bulky, too complicated and too expensive for use in certain types of machine tools.
It is also known to provide a straightening machine for tubes or bars with a first drive for the rotary head which accommodates the straightening rolls and with a second drive for the advancing means (rolls or carriages) which transports the workpieces toward and away from the revolving head. In certain instances, the two drives receive torque from a variablespeed transmission which can simultaneously change the speeds of both drives but leaves the ratio between such speeds unchanged. If the drives are independent of each other, synchronization of movements of the head and advancing means presents serious problems. On the other hand, if the two drives receive torque from a variable-speed transmission, the ratio of the two speeds remains constant at all times which afi'ects the versatility of the straightening machine because the operator is unable to vary the speed of the revolving head independently of the speed of the advancing means. Such adjustment is necessary if the diameters of workpieces vary.
SUMMARY OF THE INVENTION An object of the invention is to provide a simple, compact and reliable apparatus which can be used in machine tools or the like to control the speeds of two or more driven units in such a way that the ratio between the speeds of the units can remain constant even if the speeds are increased or reduced, and which further permits adjustments in the speed of one unit independently of the other unit or units.
Another object of the invention is to provide an apparatus of the just described character which is particularly suited for use in straightening machines for tubes, bars or analogous workpieces and which can effect an infinite number of adjustments in the ratio between several speeds as well as an infinite number of adjustments of the speed of a given unit.
A further object of the invention is to provide an apparatus which can be installed in or combined with existing machine tools. I
An additional object of the invention is to provide an apparatus which is particularly suited for regulating the speeds of hydraulic or pneumatic drive means in machine tools or the like.
The improved apparatus is used for effecting simultaneous as well as independent changes in operating speeds of driven units, particularly (but not exclusively) for regulating the speeds of straightening and advancing units in a machine for straightening or tubular or bar stock. It comprises first and second drive means respectively including first and second variable delivery pumps each having an adjustable part movable between a plurality of positions to thereby vary the delivery of the respective pump, movable first and second mechanical adjusting devices each connected with one of the adjustable parts, and control means for moving the adjusting devices simultaneously or independently of each other. The control means comprises a control member which is pivotable about a predetermined axis and includes first and second arms, and shifter means operative to respectively establish operative connections between the first and second adjusting devices and the first and second arms at selected distances from the axis. Such distances detennine the ratio between the delivery rates of the two pumps. The control member pivots in response to movement of one of the adjusting devices to thereby move the other adjusting device to a desired extent. Furthermore, the other adjusting device can be moved in response to such pivoting of the control member which does not result in movement of the one adjusting device in a direction which results in adjustment of the corresponding pump. Thus, by the simple expedient of moving the shifter means, the operator can change the speeds of the two pumps without changing the ratio of their speeds. On the other hand, by pivoting the control member while one of the adjusting devices is held against such movement which results in adjustment of the corresponding pump, the other adjusting device can be moved to adjust the corresponding pump. One of the pumps can drive a motor for the head of a straightening machine and the other pump can drive the carriages or rolls which transport workpieces lengthwise toward and away from the head.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic plan view of an apparatus which is combined with a straightening machine and serves to regulate the speeds of means for advancing and straightening the workpieces;
FIG. 2 is an enlarged plan view of the control means for the pumps in the apparatus shown in FIG. 1;
FIG. 3 is a transverse sectional view as seen in the direction of arrows from the line CD of FIG. 2;
FIG. 4 is a transverse sectional view as seen in the direction of arrows from the line A-B of FIG. 2;
FIG. 5 is a sectional view as seen in the direction of arrows from the line E-F of FIG. 2;
FIG. 6 is a view as seen in the direction of arrow X shown in FIG. 5;
FIG. 7 is a partly elevational and partly sectional view of one of the variable delivery pumps shown in FIG. 1; and
FIG. 8 is an enlarged view of certain details in the pump shown in FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. I, there is shown a portion of a straightening machine for bars 9 or analogous elongated workpieces. The machine comprises a first driven unit including a revolving head or basket 1 for straightening rolls 2 which orbit about the axis of the workpiece 9 while the latter is fed lengthwise. The drive means for rotating the head 1 comprises a hydraulic motor which drives a pulley 3a by way of a clutch 4. The pulley 3a drives a pulley 3b of the head 1 by way of endless V-belts 3. The motor 5 is connected with a first pump 6 by means of a supply conduit 50 and a return conduit 5b. The pump 6 is an axial piston pump of the variable delivery type and comprises a tank of reservoir 6A for oil or another suitable hydraulic fluid, and an adjustable part 6a which is accommodated in the tank 6A and is turnable about the common axis of two trunnions 6b. The means for pivoting the adjustable part 60 comprises a mechanical adjusting device here shown as a flexible shaft 18 having an axially displaceable core 18a. The arrangement is such that the delivery of the pump 6 varies in response to changes in angular position of the part 6a with reference to the axis of the trunnions 6b. The rotary components of the pump 6 are driven by the output shaft of an electric motor 17.
The straightening machine further comprises a second driven unit including two sets of advancing rolls 7, 7a and 8, 8a which are mounted in frames 7b, 8b respectively located upstream and downstream of the head 1. These advancing rolls are driven by a second hydraulic drive motor 10 by way of a clutch 10c, bevel gear transmissions 11-1 1a, 12-12(1, Cardan shafts 13, 15 and a connecting shaft 14. The motor 10 is connected with a second variable delivery pump 16 which is mounted mirror symmetrically with reference to the pump 6 and is of identical design. Its adjustable part 16a is pivotable about the common axis of trunnions 16b by the core 190 of a second flexible shaft 19. The tank of the pump 16 is shown at 16A. The connection between the pump 16 and the motor 10 comprises a return conduit 10b and a supply conduit 10a. The frames 7b, 8b accommodate transmissions (not specifically shown) which insure that at least one roll of each set of advancing rolls is driven to transport the workpiece 9 in a direction from the left to the right, as viewed in FIG. I, and to hold the workpiece against rotation.
The end portions 18b, 19b of the cores 18a, 19a of the flexible shafts 18, 19 are connected with shafts 24, (FIGS. 2-6) for roller followers 18c, 19c received in elongated guide portions or slots 20, 21 of arms 22a, 22b forming part of a twoarmed control lever 22 turnable on a pivot pin 23 of a support or housing 30. The shafts 24, 25 respectively carry pairs of rollers 24a, 24b and 25a, 25!: (FIG. 5) which extend into the spaces between the prongs of two forks 26a, 26b forming part of a shifter or holder 26 which is further provided with wheels 26c arranged to travel along rails or ways 29 provided in the housing 30. The holder 26 has a median portion 26d which constitutes a toothed rack and meshes with a gear 27 on a shaft 27a. Thus, the gear 27 can reciprocate the holder 26 along the rails 29 to thereby move the followers 18c, 19c lengthwise of the respective guide slots 20, 21 in the control lever 22. The shaft 270 can be rotated by a handwheel or knob 28. Such rotation changes the effective length of the arms 22a, 22b of the control lever 22 by changing the distance between the pivot 23 and the shafts 24, 25. This changes the ratio of rotational speed of the head 1 to rotational speed of the advancing rolls 7-8b because the shafts 24, 25 cause the cores 18a, 19a of the shafts 18, 19 to change the delivery of pumps 6, 16.
The shaft 25 carries a further roller 31 which is received in the elongated guide slot 32 of a displacing member here shown as a slide 33 which is reciprocable in the housing in parallelism with the end portion 19b of the core 19a in shaft 19 (see FIG. 4). A feed screw which meshes with the slide 33 carries a knob or handwheel 34 which can be rotated by hand to thereby move the slide 33 and the shaft 25 transversely of the arm 22b and to change the inclination of the control lever 22. This also causes an axial displacement of the end portion 18b of the core 18a (by way of the shaft 24) so that an adjustment in delivery of the pump 16 effects an appropriate adjustment of delivery of the pump 6. Rotation of the knob 34 can change the angular position of the lever 22 in a ciockwise or in a counterclockwise direction (compare FIGS. 2 and 6).
In the positions shown in FIG. 1, the pumps 6, 16 do not circulate any fluid because their adjustable parts 6a, are shown in starting or neutral positions. The motors 5, 10 will receive pressurized fluid to rotate the head 1 and the advancing rolls 7-80 in response to pivoting of adjustable parts 6a, 160 from their neutral positions. The ratio of r.p.m. of the head 1 to r.p.m. of the advancing rolls 7-80 depends on the diameter of the workpiece 9. Such ratio can be selected, as a function of the diameter of the workpiece 9, by rotating the knob 28, for example, until the effective lengths of the arms 22a, 22b of the control lever 22 correspond to those shown in FIG. 2, i.e., so that the shafts 24, 25 are moved as a unit in response to rotation of the gear 27 whereby the shafts 24, 25 are respectively shifted toward or away from the pivot pin 23 by the forks 26a, 26b of the holder 26.
The pumps 6, l6 begin to deliver pressurized fluid as soon as the operator begins to rotate the knob 34 which changes the inclination of the control lever 22 and thereby moves the parts 60, 160 from their neutral positions (for example, the knob 34 will move the control lever 22 from the position of FIG. 2 to that shown in FIG. 6). The quantity of pressurized fluid delivered by pumps 6, l6 depends on the inclination of the control lever 22 but the ratio or quantity delivered by pump 6 to quantity delivered by pump 16 is regulated by the knob 28.
If the straightening machine is to thereupon treat a workpiece whose diameter exceeds or is less than that of the workpiece 9, the operator can change the r.p.m. of the head 1 without changing the rotational speed of advancing rolls 7-80. This is achieved by rotating the knob 28 whereby the position of the slide 33 remains unchanged while the control lever 22 pivots on the pin 23. This causes a change in inclination of the part 6a to change the delivery of the pump 6. When the control lever 22 pivots, the roller 31 on the shaft 25 moves in the slot 32 of the slide 33 (which is parallel to the rails 29, see FIG. 6) so that the position of the core does not change, i.e., the pump 16 and motor 10 continue to drive the advancing rolls 7-8a at an unchanging speed but the speed of the head 1 changes because the am 220 of the control lever 22 changes the axial position of the core 18a and thereby changes the inclination of the adjustable part 6a in the pump 6. Thus, the ratio of the speed of advancing rolls 7-8a to the speed of the head 1 can be changed by rotating the knob 28 which controls the axial position of the holder 26 and hence the distance between the pivot pin 23 and shafts 24, 25 (effective length of arms 22a, 22b of the control lever 22). The speeds of motors 5, 10 can be changed simultaneously by rotating the knob 34 which moves the slide 33 and thereby pivots the control lever 22 by way of the roller follower 190 on the shaft 25. The holder 26 can be moved lengthwise without pivoting the control lever 22 when the axes of the shafts 24, 25 are coplanar with the axis of the pivot 23 (see FIG. 2).
An advantage of the improved control apparatus is that the ratio of rotational speeds of the motors 5, 10 can be selected and the speed of one of these motors changed infinitely by resorting to very simple motion transmitting means.
The sheaths 18A, 19A (FIG. 2) of the flexible shafts 18, 19 are connected to the holder 26 on the one hand and to tanks 6A, 16A on the other hand. As clearly shown in FIGS. 2 and 6, the cores 18a, 19a move axially only if the respective shafts 24, 25 are caused to move at right angles to the rails 29. The shaft 25 can move at right angles to such rails only if the slide 33 is moved toward or away from the rails; this is due to the fact that the roller 31 on the shaft 25 extends into the guide slot 32. On the other hand, the shaft 24 can move at right angles to the rails 29 as soon as it is moved lengthwise of the slot 20 provided that the control lever 22 is not held in the neutral position of FIG. 2. Therefore, the core 180 will move axially as soon as the control lever 22 pivots or as soon as the holder 26 moves lengthwise in other than the neutral position of the control lever, but the core 19a moves axially only in response to manipulation of the knob 34. The extent of lengthwise (axial) movement of the core 190 always equals the extent of movement of the slide 33 but the extent of axial movement of the core 18a depends on the distance between the pivot pin 23 and shaft 24 (effective length of the arm 220) as well as on the extent of angular displacement of the control lever 22, either in response to movement of the slide 33 or in response to movement of the holder 26. Thus, the holder 26 can effect axial movement of the core 180 (pivoting of the adjustable part 6a but it cannot change the axial position of the core 190 (angular position of the part 16a).
If the cores 18a, 19a are respectively connected with the shafts 25, 24, the speed of the pump 16 and advancing rolls 7-8a can be changed independently of the rpm. of the head 1. Also, the pumps 6, 16 can be utilized to drive motors in other types of machine tools, for example, in a shaving machine for tubes, bars or the like.
Flexible shafts which can be used in the apparatus of my invention are available on the market under the trade name Flexball (produced by Vofa-Werk of Diisseldorf-Oberkassel, Western Germany).
FIGS. 7 and 8 illustrate a portion of the pump 6 and motor 17. The output shaft 17a of the motor 17 carries a disc 50 which is coupled to pistons 51 reciprocable in the chambers of a cylinder 52 cooperating with a valve plate 53. The cylinder 52 rotates with the pistons 51 and shaft 170 and is accommodated in the casing of the adjustable part 6a. When the latter is pivoted about the common axis of trunnions 6b, the length of strokes of the pistons 51 changes and the motor 5 receives a greater or a lesser quantity of pressurized fluid. The conduit 50 is connected to one of the trunnions 6b. The other trunnion 6b admits oil from tank 6A to the valve plate 53. The conduit 5b discharges oil into the tank 6A.
The pump 16 is identical with the pump 6.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.
What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.
1. In an apparatus for effecting simultaneous as well as independent changes in operating speeds of driven units, particularly for regulating the speeds of straightening and advancing units in a machine for straightening of tubular or bar stock, a combination comprising first and second drive means respectively including first and second variable delivery pumps each having an adjustable part movable between a plurality of positions to thereby vary the delivery of the respective pump; movable first and second mechanical adjusting devices each connected with a different one of said parts; and control means for simultaneously moving said adjusting devices for simultaneous or independent movement of said first and second adjustable parts, said control means including a control member pivotable about a predetermined axis and having first and second arms, and shifter means operative to respectively establish operative connections between said first and second devices and said first and second arms at selected distances from said axis.
2. A combination as defined in claim 1 wherein each of said adjustable parts is pivotable between said positions thereof and each of said adjusting devices comprises a motion transmitting element which is movable lengthwise and comprises a first end portion connected to the corresponding adjustable part and a second end portion connectable by said shifter means to the correspondin arm of said control member.
3. A combination as de med in claim 2 wherein each of said adjusting devices comprises a flexible shaft including an axially movable core constituting the respective motion transmitting element.
4. A combination as defined in claim 2, wherein said arms are provided with elongated guide portions and the second end portions of said motion transmitting elements include followers arranged to move lengthwise of said guide portions in response to pivoting of said control member and in response to operation of said shifter means.
5. A combination as defined in claim 4, wherein said shifter means comprises a holder which is reciprocable in a direction at right angles to said axis and comprises a pair of forks each having prongs flanking one of said followers and permitting movement of such follower substantially at right angles to said direction.
6. A combination as defined in claims 5, wherein each of said followers comprises a shaft parallel to said axis and further comprising rollers provided on said shafts and engaging the respective prongs 7. A combination as defined in claim 5, further comprising means for reciprocating said holder.
8. A combination as defined in claim 7, wherein the means for reciprocating said holder comprises a toothed rack provided on said holder, a gear meshing with said rack, and means for rotating said gear.
9. A combination as defined in claim 1, wherein said control means further comprises displacing means for moving one of said adjusting devices to thereby move the other adjusting device by way of said control member.
10. A combination as defined in claim 1, wherein said arms include elongated guide portions and each of said adjusting devices comprises a follower arranged to travel along the respective guide portion, said shifter means comprising a holder reciprocable in a direction at right angles to said axis and having a pair of forks each including prongs flanking one of said followers and permitting movement of such follower at right angles to said direction, said displacing means comprising a slide movable at right angles to said direction and having guide means receiving a portion of one of said followers and extending in parallelism with said direction.