US 3577684 A
Description (OCR text may contain errors)
United States Patent  References Cited UNITED STATES PATENTS .463.287 3/1949 Krueger....i.............. 3.008276 Inventor ZigmantJakimcius Rockford, [11. 787.656
 Appl. No.
 Filed Dec. 30, 1968  Patented May 4, 1971  Assignee Barnes Drill Co.
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885 5 3MMB ns s b 41 2/ 1 5 mf o m cm U mm 1 l] 2 0 5 55 l [I mounted for swinging toward and away from a second roll for driving the belt and is urged continuously away from the driving roll by a tensioning actuator to tension the belt and keep the latter taut on the rolls as the belt stretches during service use.
PATENTEDHAY 4m: 3,577, 84
SHEET 2 [IF 3 Ukvramwfi YJ BACKGROUND OF THE INVENTION This invention relates to an abrading machine of the type in which an'endless belt is trained around and tensioned between at least two rolls and, more particularly, to an abrading machine in which one of the rolls is a steering roll adapted to be tilted alternately to oppositely inclined positions to induce edgewise travel of the belt back and forth across the rolls. Usually, the other roll is power rotated by a drive motor to propel the belt around the rolls as an incident to the performance of an abrading operation. The belt, of course,
stretches during service use and normally is kept under tension on the rolls as such stretching occurs by moving one of the rolls gradually away from the other roll to take up the slack in the belt.
SUMMARY OF THE INVENTION The primary aim of the present invention is to simplify the construction of an abrading machine of the above character and to render the machine more trouble free in operation by using the steering roll not only to induce edgewise travel of the belt'but also to keep the belt tensioned continuously on the rolls. With such an arrangement, the need for mounting more than one roll for bodily movement is avoided and, at the same time, there is no requirement of a relatively complex flexible or adjustable drive between the power roll and the drive motor as otherwise might be necessary to accommodate swinging of the power roll if the latter were used to tension the belt.
A more detailed object is to achieve the foregoing by mounting the steering roll for swinging toward and away from the power roll as well as for tilting between oppositely inclined positions and by continuously urging the steering roll to swing away from the power roll to keep the belt under constant tension.
Theinvention also resides in the unique construction of the mounting for the steering roll and particularly in the novel use of a steering eccentric about which the steering roll swingsto tension the belt but which also oscillates back and forth to cause tilting of the steering roll.
Another object of the invention is to provide an adjusting eccentric which swingably mounts the steering roll and which may be adjusted selectively to correlate the tilted position of the roll with the angular position of the steering eccentric.
Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a fragmentary side elevation of a new and improved abrading machine embodying the novel features of the present invention.
F 16.2 is a fragmentary end view of the machine taken along the line 2-2 of FIG. 1.
FIG. 6 is a perspective view of the steering roll and other parts shown in FIGS. 1 to 5. I
FIG. 7 is a perspective view of the steering eccentric and associated elements.
' FIG. 8 is a perspective view of the adjusting eccentric and associated elements.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the drawings for purposes of illustration, the in- 5 vention is embodied in an abrading machine 10 in which an endless abrasive belt 11 (FIG. I) is trained around and tensioned between three generally horizontal rotary rolls 12, I3 and 14 arranged in a triangle on a support or head 15 to guide the belt along a triangular path with the belt contacting a workpiece (not shown) located below the lower roll 12. The workpiece is supported on a conveyor (not shown) for advancement beneath the belt as the latter is driven at high speed around the rolls by rotating the roll 13 with a drive motor 16. Thus, the roll I2 constitutes a working roll while the roll 13 constitutes a driving roll.
Herein, the head 15 is mounted on a supporting arm 17 (FIG. I) projecting cantilever fashion from an upright column 18 and overlying the workpiece and the working roll 12. A head which is suited generally for use with the present invention is described in detail in US. Pat. No. 3,008,276 to which reference is made.
To maintain the belt 11 substantially centered on the rolls l2, l3 and 14 and to avoid repetitive and overlying cuts on the surface of the workpiece, controlled edgewise travel of the belt back and forth across the rolls and the workpiece is induced by tilting the roll 14 first upwardly and then downwardly between two oppositely inclined positions during the abrading operation. In this instance, tilting of the roll 14, hereafter referred to as the steering roll, is effected by a steering actuator 19 (FIGS. 1 and 3) comprising a cylinder 20 pivotally connected at one end to the head 15. In response to the admission of air alternately into opposite ends of the cylinder, a piston 21 with a piston rod 22 is reciprocated back and forth within the cylinder to extend and retract the rod and thereby tilt the steering roll between its positions. To control the actuator, pneumatic signals are produced by a sensing nozzle 23 (FIGS. 1 and 2) and receivers (not shown) positioned along one edge of the belt and cause the piston and rod to extend as the belt reaches one limit of its edgewise travel and to retract as the belt reaches its other limit. One type of suitable control system is shown in US Pat. No 3,363,366.
During repeated service use, the abrading belt -11 stretches and increases in length. To compensate for such stretching and to keep the belt tensioned around the rolls 12', I3 and 14, it is customary to force one of the rolls to move gradually away from the other rolls and into pressing engagement with the belt to take up the slack in the belt.
According to the primary aspect of the present invention, the steering roll 14 itself is utilized to tension the belt 11 as well as to cause back and forth edgewise travel of the belt in order to simplify both the construction and operation of the abrading machine 10. For these purposes, the steering roll is mounted in a unique manner to tilt upwardly and downwardly to steer the belt and, in addition, is mounted and urged to swing away from the driving roll 13 and into continuous pressing engagement with the inner face of the belt to keep the latter constantly tensioned on the rolls as stretching occurs. With the steering roll thus also serving as a tensioning roll, the drive roll 13 can be mounted nonswingably on the head 15 in a simple manner and, more importantly, the drive motor 16 can be supported in a stationary position without need of an adjustable drive connection between the motor and the drive roll.
In the present instance, the steering roll 14 is mounted swingably and tiltablv on the head by a pair of upright arms 24 and 25 (FIG. 6) which are mounted on the support 15 at their upper ends by pivot members 26 and 27. The steering roll 14 is mounted on the arms 24 and 25 by trunnions 28 which are joumaled by universal self-aligning bearings 29 (FIG. 4) located at the midpoints of the arms. The right end (FIG. 6) of the steering roll tilts about the left end and the left bearing 29 when the roll is moved between its oppositely inclined positions.
' forthe arm 24 at the right end of the steering roll (FIG. 6) is a steering eccentric which is joumaled for oscillation in a bushing 30 (FIG. 4) in the arm. Referring to FIG. 7, it will be seen that the steering eccentric 26 includes a pin 31 rigid with and extending axially through a cylindrical disc 32 which is parallel to but offset from the axis of the disc. To support the arm 24, the head includes a triangular-shaped bifurcated leg 33 (FIG. 4) in whichthe pin 31 is journaled to suspend the arm between the branches 34 and 35 of the leg. Rigid with the pin 31 and extending upwardly past the disc 32 and the leg 33 is a crank arm in the form of an ear 36. Connected pivotably to the upper end of the ear is the piston rod 22 of the steering actuator 19 (See FIG. 6). At its head end, the cylinder of the steering actuator 19 is pivoted to a plate 38 (FIG. I) which is rigid with part of the head 15. When the steering actuator is activated, extension and retraction of the piston rod oscillates the pin 31 back and forth about its axis. As the pin oscillates, the disc 32 is rocked back and forth within the bushing and,
- by virtue of the eccentricity of the disc with respect to the pin,
the arm 24 is raised and lowered to cause up and down tilting of the steering roll 14.
Swinging movement of the steering roll M to tension the belt 11 is effected by a tensioning actuator 39 (FIG. 3) comprising a cylinder 40 pivotably connected at one end to the head 15. In response to the admission of air under pressure into the head end of the cylinder 40, a piston 41 is pushed forward to extend a rod 42 and thereby swing the steering roll about the pivot member 27 and the disc 32 and into continuous pressing engagement with the belt 11 to tension the latter. To transmit the force from the tensioning actuator 39 to the steering roll, a link 43 (FIG. 6) is pivotably connected at one end to the piston rod 42 and is rigid at its other end with a rock shaft 44. The rock shaft is joumaled in the head 15 and carries at its ends a pair of cranks 45 and 46 which are fast on the rock shaft. Pivotably connected to the lower ends of the cranks 45 and 46 are the ends of two links 47 and 48 whose other ends are connected pivotably to the lower ends of the arms 25 and 24, respectively. As the piston rod 42 is extended, the arms 24 and 25 are urged in a clockwise direction (FIG. 6) and pivot about the pivot member 27 and the disc 32 to swing the steering roll 14 away from the drive roll 13 and into pressing engagement with the belt 11. Accordingly, it will be apparent that the steering eccentric 26 formed by the pin 31 and the disc 32 may be turned back and forth to tilt the steering roll 14 upwardly and downwardly and also serves as a pivot member about which the steering roll may swing for purposes of tensioning the belt.
Advantage is taken of the pivot member 27 in the arm 25 (left side of FIG. 6) to correlate the tilted position of the steering roll 14 with the angular position of the steering eccentric 26 when the machine 10 is set up initially. Herein, the pivot member 27 is an adjusting eccentric comprising a pin 49 (FIG. 8) rigid with and extending axially through a cylindrical disc 50. The pin is parallel with but ofi'set from the axis of the disc 50 and is joumaled in the arm 25. To support the arm, the head 15 includes a second triangular-shaped bifurcated leg 51 (FIGS. 1 and 2) in which the pin 49 is joumaled thereby suspending the arm between the branches 52 and 53 of the leg. At one end, the pin 49 carries a cylindrical plate 54 and is held at its other end to the leg by a nut 55. Within one edge portion of the plate 54 is threaded a set screw 56 for locking the pin 49 against rotation.
To obtain the same amount'of tilting movement in both directions, the steering roll 14 must be level when the steering eccentric 26 is midway through its oscillating stroke, such positioning usually occurring when the piston 22 of the steering actuator 19 is at the midpoint of the cylinder 20. With the initial adjustment made available as a result of the adjusting eccentric 27, the piston rod 22 may be connected to the car 36 of the steering eccentric and then the piston 21 may be moved to the midpoint of the cylinder 20, thus determining the position of the right end (FIG. 6) of the steering roll. Thereafter,
the adjusting eccentric 27 can be rotated to raise or lower the left end of the steering roll until the steering roll is level, and then the adjusting eccentric may be locked against further rotation by tightening the setscrew 56. During service use, the
- steering roll 14 can become worn unevenly or the belt 1! can become stretched unevenly thereby making an adjustment to the extent of tilting in one direction or the other desirable or necessary. This adjustment can be made by resetting the adjusting eccentric 27.
From the foregoing, it will be apparent that the novel arrangement of the steering eccentric 26 and the adjusting eccentric 27 joumaled in the arms 24 and 25, respectively, not only allows the steering roll '14 to be used to control travel of the belt 11 but also enables the roll to be moved into continuous pressing engagement with the belt thereby tensioning the belt. As a result, only one roll need be movable to effect both steering and tensioning thereby simplifying the construction of this type of abrading machine and reducing the amount of servicing required by the machine.
I. In an abrading machine, the combination of, a support, driving and steering rolls each having ends joumaled on said support for rotation about generally parallel axes,'an endless abrading belt trained around said rolls and movable about the rolls as an incident to rotation of said driving roll, means mounting said steering roll on said support for tilting of the steering roll about one of its ends between oppositely inclined positions and also for back and forth movement toward and away from said driving roll, a fluid-operated and cyclically reciprocable steering actuator connected to said steering roll and operable when reciprocated to tilt the steering roll alternately in opposite directions between said positions to induce back and forth edgewise travel of the belt across said rolls, and a tensioning actuator connected to and exerting a continuous force on said steering roll to urge the latter to move away from said driving roll and into pressingengagement with said belt thereby to keep the belt tensioned between said rolls.
2. An abrading machine having a support, driving, working and steering rolls arranged in a'triangle on said support and joumaled on the latter for rotation about generally parallel axes, an endless abrading belt trained around said rolls and gagement with the belt for tensioning the latter, said mounting means including an arm connected to the steering roll, an ec-- centric joumaled in said arm and mounting the arm for swinging, a steering actuator connected to said eccentric and operable to rock the latter within said arm to tilt the steering roll alternately in opposite directions and thereby induce back and forth edgewise travel of the belt across the rolls, and a tensioning actuator connected to one end of said arm and exerting acontinuous force urging the arm to swing about said eccentric whereby said steering roll is maintained in pressing engagement with said belt to tension the latter.
3. In an abrading machine, the combination of, a support, driving and steering rolls joumaled on said support for rotation about generally horizontal axes, an endless abrading belt trained around said rolls and movable about the rolls as an incident to rotation of said driving roll, means mounting said steering roll on said support for up and down tilting between oppositely inclined positions and also for back and forth swinging about a generally horizontal axis toward and away from said driving roll, said means comprising a pair of generally upright arms disposed alongside and fastened toopposite ends of the steering roll, a pivot member connected to each of said arms and supporting the latter and said steering roll for swinging toward and away from said driving roll, at least one of said pivot members being a generally cylindrical disc rotatably received in its respective arm and supporting such arm for swinging about the disc, a pin connected to and the axis of said pin and within saidone arm thereby to cause a the latter to shift up and down and tilt said steering roll between said positions, and a tensioning actuator connected to said arms to swing the arms away from said driving .roll and about said disc andthe other pivot member thereby to press said steering roll against said belt to tension the belt on rolls. a
4. A machine as defined in claim3 in which said pin is fast on and extends axially of said disc and is journaled for turning on said support.
5. A machine as defined in claim 4 further including a crank rigidly attached to said disc and pivotably attached to said steering actuator. g
6. A machine as defined in claim 3 in which said support includes a support arm with bifurcations, said pin being the 'pivotab ly'mounted between the bifurcations of said support arm.
I. Amachine as defined in claim 3 further including a member connected pivotably to said arms and extending generally parallel to said steen'ngroll, said tensioning actuator being connected to said member to swingsaid arms in unison.
8. A machine as defined in claim 3 in which the other of said pivot members is a second generally cylindrical disc rotatably received in its respective arm and supporting such arm for swinging aboutthe disc, a second pin fastened to and eccentric with said second disc and joumaled for selective turning on said support whereby turning of the'pin turns the second disc to cause vertical shifting of the associated arm, and means selectively operable to lock the second pin against turning whereby such pin may be turned to adjust the second arm to a predetermined vertical position and then locked to retain the second arm in such position.