US3520089A - Grinding machine - Google Patents

Description

Jul 14, 1970 Filed July 19, 1967 F. M. OWREY ETAL GRINDING momma 5 Sheets-Sheet l JNVFNTn FRANCIS M. OWREY ADOLPH C. CARLSON RICHARD D. RUTT July 14, 1970 F. M. OWREY ETAL 3,520,089

GRINDING MACHINE Filed. July 19, 1967 3 Sheets-Sheet 2 INVENTOR.

62 FRANCIS M. OWREY ADOLPH C. CARLSON FIG. 3 BY RICHARD 0. RUTT United States Patent Office 3,520,089 Patented July 14, 1970 3,520,089 GRINDING MACHINE Francis M. Owrey, Niagara Falls, Richard D. Rutt, Wilson, and Adolph C. Carlson, Grand Island, N.Y., as-

signors to The Carborundum Company, Niagara Falls,

N.Y., a corporation of Delaware Filed July 19, 1967, Ser. No. 654,578 Int. Cl. B24b 21/12 US. Cl. 51141 9 Claims ABSTRACT OF THE DISCLOSURE A grinding machine having a contact roll for pressing an abrasive belt against a workpiece. A rack and pinion air-activated lock-up mechanism is provided for automatically positioning the cantilevered end of a contact roll support and locking the same in such position to maintain the contact roll parallel to a workpiece support.

DISCLOSURE This invention relates to grinding machines and, more particularly, to a new and improved mechanism for locking a contact roll in a fixed position.

Grinding machines of the abrasive belt type generally have a cantilevered grinding head which carries a drive roll and a contact roll about which an endless abrasive belt. is trained. Support members are provided at opposite ends of the head for receiving the ends of the contact roll shaft. The grinding head is secured adjacent one end to the frame of the grinding machine, the other end being free. Since the free end will move in response to loads applied during the grinding operation it has been the general practice to provide means for retaining the free end fixed by means of a swinging arm which is ivotably supported at one end adjacent the bottom of the frame of the machine and is usually provided with a slot or opening at the other end for embracing a threaded projection extending axially from the contact roll support member. A nut secures the arm to the threaded projection.

Although such devices have served the purpose for which they were designed, they have not been entirely satisfactory because of the labor and inconvenience in releasing the arm and swinging it to an open position to permit the belt to be removed when belt replacement is required. Moreover, the contact roll is not always repositioned accurately relative to the workpiece support after insertion of a new belt causing uneven wear and a shortened useful life of the abrasive belt.

The contact roll locking means of the present invention,,as hereinafter described, obviates the above noted disadvantages by providing rapid and automatic release of the locking means when belt replacement is desired and accurate repositioning of the contact roll relative to the workpiece support after installation of a new belt.

It is, therefore, an object of the present invention to provide a new and improved grinding machine.

It is another object of the present invention to provide a new and improved grinding machine having novel locking means for retaining a contact roll support memher in a fixed position relative to the workpiece support.

It is a further object of the resent invention to provide a new and improved grinding machine having a novel contact roll support locking means which is compact, simple and strong in construction, rapid and efiicient in its operation, and rugged and durable in use.

It is a more specific object of the present invention to provide a new and improved grinding machine having a novel fluid actuated rack and pinion mechanism for locking a contact roll support member in a fixed position parallel to the workpiece support.

These and other objects of this invention will become more apparent upon consideration of the following detailed description thereof when taken in conjunction with the following drawings, in which:

FIG. 1 is an isometric view of a grinding machine in which a preferred illustrative embodiment of the invention is incorporated;

FIG. 2 is an enlarged, fragmentary end elevational view of the contact roll support locking means constructed in accordance with the principles of this invention;

FIG. 3 is an enlarged fragmentary end elevational view showing the contact roll support locking means in the open position;

FIG. 4 is a vertical sectional view taken on the plane of line 44 of FIG. 2;

FIG. 5 is a diagrammatic view illustrating the fluid circuit for the contact roll support locking means.

Referring to the drawings and particularly to FIG. 1, it will be observed that a preferred embodiment of the invention constructed in accordance with the principles of this invention is incorporated in a grinding machine, generally designated 10, consisting of an upright frame 14 suitably supported on a ground surface. The terms upper, lower, left-hand, right-hand, and the like as used herein are applied only for convenience of description and should not be taken as limiting the scope of this invention.

Frame 14 contains a grinding head, generally designated 16, having an upper roll (not shown) suitably journaled for rotation in bearing blocks 18 (only one shown in FIG. 1) at either end thereof and suitably driven by an electric motor (not shown) in a manner wellknown in the art. A contact roll 20 (see FIG. 4) is mounted for rotation adjacent the bottom of grinding head 16 and an endless abrasive belt 22 is trained about roll 20 and the upper roll (not shown) for movement in an orbital path. It should be appreciated that the principles of this invention contemplate driving the roll 20 rather than the upper roll, if desired.

Frame 14 is provided with beams 24 and 26 extending outwardly from both ends thereof and disposed on both sides of the frame for supporting rollers 28 and 30 journaled for rotation in bearings 32 and 34 mounted adjacent the ends of beams 24 and 26, respectively. An endless conveyor belt 36 is trained about rollers 28 and 30 for the purpose of advancing workpieces beneath abrasive belt 22 in the direction of the arrow shown in FIG. 1. The means for driving the conveyor belt 36 may be of any conventional variety, and since many such arrangements are known in the art, no illustration or further explanation is believed necessary.

With reference to FIG. 4, it will be seen that contact roll 20 is provided with a shaft 40 rigidly secured to and rotatable with the inner race 42 of a bearing assembly 44, which is mounted in a contact roll support member or bearing block 46 suitably attached to the grinding head 16. It should be appreciated that only one end of the contact roll is illustrated, namely, the left end as seen in FIG. 4, the other end being similarly journaled in a suitable support member in the same manner as the portion shown. It should also be noted that the grinding head is secured to the frame of the grinding machine adjacent the end remote from that shown in FIG. 4 and that the left end of the head and the corresponding left end of the contact roll support member are cantilevered. Accordingly, some means is necessary to retain this portion of the head and roll fixed in order to preclude undesirable movement of the roll in response to loads applied during the grinding operation.

A locking mechanism, generally designated 50, is provided adjacent the bottom of grinding head 16 for retaining the contact roll support member in a fixed position during operation. With reference to FIGS. 2, 3, and 4 of the drawings, it will be seen that the locking mechanism comprises a pair of plates 52 and 54 of substantially semi-circular configuration secured to the grinding head 16 by means of suitable bolts 56. Plates 52 and 54 may have shapes other than semi-circular within the purview of the present invention. Plates 52 and 54 are provided with a pair of guides 58 and 60 for receiving a positioning rack 62 and a locking rack 64, respectively. Positioning rack 62 is secured at one end to a piston rod 66 of a piston contained in a pneumatic cylinder 68 suitably supported on conveyor frame 14. The other end of positioning rack 62 is engageable with a rod 70 ad jacent to the grinding head 16 for activating a pneumatic control valve 72 for a purpose hereinafter more fully explained.

A rod 74 which is secured to one end of a toggle linkage 76 is pivotally connected to a bell crank 78 in turn pivotally mounted on a bolt 80 secured to grinding head 16. Also connected to bell crank 78 is a piston rod 82 having a piston contained in fluid cylinder 84 suitably mounted on grinding head 16. Racks 62 and 64 mesh with a pinion gear 86 carried by a shaft 88 journaled in the grinding head 16. A stop 90 is mounted on the frame 14 for engaging the bottom end of locking rack 64 and limiting the downward movement thereof. An abutment member 92 is suitably secured on frame 14 by means of a bolt 94 and is provided with an inclined surface 96. Rack 64 is provided with a complementary inclined surface 98 adjacent the bottom thereof for a purpose hereinafter more fully explained.

A pneumatic cylinder 100 is secured onto a plate 102 mounted on frame 14 and contains a suitable reciprocable piston having a piston rod 104. The end of piston rod 104 is provided with a bearing nut 106 engageable with the outer surface of plate 52.

Referring now to the diagrammatic showing of the pneumatic circuit in FIG. 5, it will be observed that a pressure line 110 is connected to a suitable source of air (not shown) and is provided with a filter 112 for purifying the air before it enters the system. Pressure line 110 is connected to a directional valve 114 having a spool valve, the position of which is controlled by a solenoid 116 and a spring 118. Leading from valve 114 are a supply conduit 120 and a return conduit 122, conduit 120 being connected to the head end of cylinder 168 by means of conduit 124 and to control valve 72 by means of conduit 126. A restricted passage 128 is provided in conduit 120 to slow the flow of fluid in one direction but is bypassed in the return direction by a conduit having a check valve 130. Return conduit 122 is connected to the rod ends of cylinders 68, 84 and 100 by means of conduits 132, 134 and 136, respectively. A restrictive passage 138 is provided in conduit 122 and may be bypassed by a conduit having a check valve 140. Control valve 72 is connected to the head end of cylinder 84 by a conduit 142 and to the head end of cylinder 100 by a conduit 144. A restricted passage 146 is provided in conduit 144 which may be bypassed by a check valve 148. Although the above circuit has been described as a pneumatic system, it should be appreciated that the principles of this invention contemplates the use of a hydraulic system, if desired.

The mode of operation is as follows:

When an abrasive belt is to be replaced, the locking means is opened as shown in FIG. 3 to permit removal of the old belt and insertion of a new belt. After installation of an abrasive belt on grinding head 16, a control element on control panel is actuated to energize solenoid 116 (see FIG. 5) to displace valve 114 against the bias of spring 118 until the position A is aligned with the Supply and return conduits to supply 4 air pressure through conduit 120 to the head end of cylinder 68, thereby urging positioning rack 62 upwardly. As positioning rack 62 moves upwardly, it rotates pinion gear 86 in a counterclockwise direction as shown in FIG. 2 to effect downward movement of locking rack 64 to bring the bottom end thereof to within a relatively short distance from stop 90. When rack 62 has reached the end of its upper movement, which is determined by the limits of the cylinder stroke, rod 70 is actuated by the end of said rack to displace valve 72 to the position shown in FIG. 5 whereby conduit 126 is connected to conduits 142 and 144. Since there are no restrictions in conduit 142, pressure builds up quickly at the head end of cylinder 84 to move piston rod 82 downwardly to the position shown in FIG. 2 and pivot bell crank 78 in a counterclockwise direction about bolt 80. Toggle linkage 76 is swung to a vertically oriented position to bring rod 74 against the top end of rack 64 and maintain the same in a locked position between rod 74 and stop 90. Accordingly, the cantilevered free end of the contact roll support member is now fixed in the vertical direction.

An important feature of the present invention is that the sudden impact of rod 74 driving rack 64 against stop 90 effects final rotation of pinion gear 86 to apply a tremendous downward force to the grinding head while placing piston rod 66 in tension to positively accurately position the contact roll parallel to the workpiece support.

By the time piston rod 82 has reached the end of its' stroke, pressure which has built up slowly through restrictive passage 146 in the head end of cylinder 100 Will be sufficient to move piston rod 104 to the left as seen in FIG. 2 to bring bearing nut 106 against the outer surface of plate 52 and clamp the same against abutment member 92 to lock the contact roll in the horizontal 'direction. To release the locking mechanism, a control ele-' ment is actuated on control panel 150 to tie-energize solenoid 116 and displace valve 114 until the position B of the valve is aligned with the supply and return conduits to supply pressure fluid to the rod ends of cylinder 68, 84 and 100 and evacuate pressure from the respective head ends thereof.

As a result of this invention, an improved grinding machine is provided for readily facilitating the replacement of abrasive belts in an improved and more efficient manner. By the provision of a novel locking means, the contact roll support member, which is attached to the cantilevered end of the grinding head, is' retained in a fixed position and will not respond to applied loads induced during operation. Another advantage residing in the use of this invention is that the locking mechanism may be automatically and rapidly released when belt replacement is desired and accurate, positive, repositioning of the contact roll relative to the workpiece support is insured after belt installation.

A preferred embodiment of this invention having been described and illustrated, it is to be realized that modifications thereof may be made without departing from the broad spirit and scope of this invention as defined in the appended claims.

We claim:

1. A belt grinding machine comprising: a frame; a horizontal workpiece support; a grinding head mounted on said frame and having a drive roll and a contact roll about which an abrasive belt is trained; support members mounted on said head for rotatably receiving the opposite ends of said contact roll; said head having a fixed end and a cantilevered end, said cantilevered end being free in non-operating position and locked in operating position; and means for selectively locking said cantilevered end to maintain said contact roll in a horizontal position parallel to the workpiece support and for unlocking the same.

2. A grinding machine as defined in claim 1 wherein said locking means comprises a pair of elongated, spaced racks engageable with a pinion gear rotatably journaled in the cantilevered end of said head.

3. A grinding machine as defined in claim 2 wherein said racks are disposed perpendicular to a horizontal plane passing through the center line of said contact roll.

4. A grinding machine as defined in claim 3 wherein the top end of one of said racks is disposed below the contact roll while the bottom end of the other of said racks is disposed above the bottom of the periphery of the contact roll to permit removal and replacement of an abrasive belt in the unlocked position of the locking means.

5. A grinding machine as defined in claim 4 wherein first fluid power means are connected to the bottom end of said one of said racks for actuating the same upwardly to eflect downward movement of the other of said racks through means of said pinion gear.

6. A grinding machine as defined in claim 5 wherein a stop is provided on the frame below said bottom end of the other of said racks, and means mounted on the grinding head are actuated to move the other of said racks downwardly to drive the bottom end of said other of said racks against the stop.

7. A grinding machine as defined in claim 6 wherein said last mentioned means comprises a second fluid power means connected to said head, a toggle linkage being connected to said second fluid power means and having a rod engageable with the top end of said other of said racks.

8. A grinding machine as defined in claim 7 including a second stop on said frame, and third fluid power means for maintaining the other of said racks against said sec 0nd stop to preclude horizontal movement of said contact roll.

9. A grinding machine as defined in claim 8 including a fluid circuit in which said first fluid power means, said second fluid power means, and said third fluid power means are actuated in a timed relationship.

References Cited UNITED STATES PATENTS OTHELL M. SIMPSON, Primary Examiner US. Cl. X.R.

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