US1753590A - Workholder for bar-grinding machines - Google Patents

Description

April 8, 1930. F. K. BENEDICT WORKHOLDER FOR BAR GRINDING MACHINES 3 Sheets-Sheet 1 Filed Dec. 27, 1927 IN VEN T 0 1? BYF/PEDE/P/C A. BENEDICT April 8, 1930. F. K. BENEDHCT 1,753,590

WORKHOLDER FOR BAR GRINDING MACHINES Filed Dec 27, 1927 s sheets-sheet 2 16 \l GD 6 [7 -12 D Q Q 0 9 r O we 7 10 v R INVENTOR FREUL'R/C K. 5'/v0/cr A TTORNE Y April 8, 1930. F. K.

' WORKHOLDER FOR BAR GRINDING MACHINES BENEDICT s Sheets-Sheet 5 Filed Dec. 2'7, 1927 INVENTOR F/Q fDE/P/C A? BDVEU/CT TZ'ORNEY Patented Apr. 8, 1930 FREDERIG K. BENEDICT, OF BIG RAPIDS, MICHIGAN, ASSIGNOR TO COVEL-HANCHETT (30., OF BIG RAPIDS, MICHIGAN, A CORPORATION MICHIGAN WORKHOLDER FOR BAR-GRINDING- MACHINES Application filed December 27, 1927. Serial No. 242,795.

This invention is a work-holder for a grinding machine used for grinding the flat working faces of bars, and for face-grinding other heavy work of like character.

My invention comprises a work-holder that is rotatable about its central vertical axis, and is provided with work-clamping and releasing means on both sides. Novel centering devices and locking mechanism for accurately positioning and locking the work-holder with respect to the grinding element are also provided on the rotatable work-holder. The grinding element is a motor-driven grinding wheel mounted on a carriage that travels back and forth along the face of "the work.

An object of my invention as claimed is to provide a rotatable work-holder that presents a piece of work to the grinding wheel and while it is being faced off a second piece of work is being mounted and accurately positioned and clamped on the back of the workholder. When the first piece is finished the holder is rotated to accurately present the second piece of work to the wheel. r

The invention includes novel means for easily clamping the work on the work-holder, for adjusting it inwardly toward and from the working plane of the grinding wheel, for tilting the upright face to be'worked toward or away from the working plane of the wheel, and gauging means for setting the face of the bearing patches on the bar in a true vertical plane in order that the finished Working face shall be parallel with the face of the patch. A locomotive guide bar is a heavy piece of work quite wide and several'feet long, and its working face, on which the engine cross head is to slide, must be ground to a true plane and it must also be parallel with thefaced pads or 49 bearing surfaces that are provided on the back face of the bar'near its ends. Ease and accuracy in setting and adjusting these heavy pieces of work on the vertical work-holder while another piece is being ground are essen- 5 tial considerations, and the novel means for within a housing 2 is attaining that facility of handling is part-0f my claimed invention.

Another advantage is that the grinding wheel and its supporting carriage can be run out of the way by continuing along the extended track on which it travels, to permit the work-holder to be, rotated and thereby present a new piece of Work to the grinding wheel, after which the wheel can be returned without having disturbed its accuracy.

lVith the foregoing and certain other objects in View which will appear later in the specifications, my invention comprises the devices herein described and claimed and the equivalents thereof.

In the drawings Fig. 1 is a front perspective view of the machine while grinding.

Fig. 2 isan end view of the work-holder in perspective.

a Fig. 3 is a perspective view showing the work-holder while being rotated, the grinding wheel mechanism at the end of its travel to clear the work-holder.

Fig. 4 is a rear view of an end of the workholder, partly broken away, showing the locking device.

' Fig. 5 is an end view, partly broken away.

Fig. 6 is a detail View of the plunger that locks the turn table.

As clearly shown in the drawings a cupshaped grinding wheel -1 suitably mounted driven by a motor 3 through a silent chain 4.

The housing is traversed along ways 5 in the manner common in this class of machines. Alongside the ways 5 is a bed or platen 6, upon which the work-holder which forms the subject of my invention is mounted.

Considered in its broader aspect the workholder comprises a turn-table 7 revolvablein a horizontal plane around a vertical axis. Near the ends of the turn-table are upright work-supporting cradles 8 adapted to hold two pieces of work, one on the front of the turn-table and one on the back.

\Vhile one of the pieces A is being faced 01f by the grinding wheel the other piece B is being mounted on the turn table, the workman standing at the back, or right-hand side cf the machine, as represented in Fig. 1, while setting the work. The piece B is placed in the cradles 8, the ends of its lower edge resting on blocks 9 which are equipped with means operated by adjusting screws 10 whereby the face of piece B can be slightly tilted away from vertical, as lines. Such a tilting movement is some times necessary in order to set the work so that the back face of the bearing pad 11 on the 3nd of the work will lie in a plane parallel with the working plane of the grinding wheel. Parallelism of the wheel and. the pad insures that the wheel will dress the outer face of the guide to a plane that is exactlyparallel with Lhe bearing faces of its end pads 11. A gauge plate having a straight-edge 12 is slidable toward and from the face'of the patch 11, to enable the operator to accurately gauge the setting of the work. The gauge plate may be clamped in place by a set screw 13.

The tilting mechanism actuated by screw 10 is shown in side view in Fig. 5, where 1a is a work-supporting bar concealed within the block 9 and pivotally mounted, as at 15, so that downward thrust'of adjusting screw 10 raises the outer end of bar 1a and tilts it slightly, correspondingly tilting the guide bar 7B. The bar is then clamped down by screws 16 and is backed up by adjusting screws 17 which are carried by the cradles 8. To ascertain whether the piece B when set up on the back of the turn-table in the way above described has been accurately aligned with the working face of the grinding wheel 2, face gauges 18, 18 are mounted on the back edge of platen'6. They are hinged at their bottoms to brackets 19 and can be folded down out of the way when the turn-table revolves, as shown in Fig. 3. By raising these two gauges and sweeping them in the arc of a circle over the front face of work B the correctness of the setting can be determined by inspection.

When the turn-table is in the position shown in Fig. 1 its ends rest on supporting blocks 20 and are clamped down to those blocks by means of a screw and lug 21.

To insure accuracy of longitudinal alignment of the turn-table with the working plane of the grinding wheel I provide a locking plunger 22, Fig. 6, the end of which normally engages an accurately formed recess 23 in the under side of the turn-table. A spring 24 concealed in a cavity of the plunger serves to keep the plunger normally raised, and a pivoted handle 25 when lifted retracts the plunger and releases the turn-table so it can be revolved.

After the working face of piece A has been finished by the grinding wheel 1 the wheel indicated by dotted and its associated driving mechanism on housing 2 is run past the turn-table far enough to allow the table to swing, as shown in Fig. 3, to present piece B to the grinding wheel for the next operation.

The turn-table is preferably mounted upon anti-friction bearings 26 carried by the stationary platen 6, as shown in Figs. 4: and 5.

I In operating the machine'the piece B is first stood on edge on the tiltable blocks 9, 9 and its back pad faces are set vertical by gauges 12 and adjusting screws 10, after which the work is clamped down by screws 16 and supported at its back by adjusting screws 17 The face gauges 18 are then used to check up the accuracy of the setting as they are properly located to represent the true position of the working face of grinding wheel 1 with respect to piece B for reversing the turn-table.

By the means above described I have produced a machine for grinding the faces of locomotive cross heads or guide bars and for other grinding or polishing work that requires the grinding of a true fiat surface of considerable length and width in a plane that is parallel with and equidistant from the faces of the bearing pad surfaces that are on the back of the work. 7

Moreover, I have provided novel means for mounting the work, for accurately placing it prior to grinding so as to present it correctly to the grinding wheel.

I have also provided'a work-holding platen carrying a pair of cradles at each side whereby a piece of work can be accurately positioned on one pair of cradles While another piece, previously mounted in the opposite pair of cradles, is being ground.

In practice the machine can be kept in practically continuous operation, since the operator can mount and accurately position one piece of work while the grinding wheel is automatically facing a previous 1 piece of work.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a machine for face-grinding locomotive guides and similar work, a turn table having upright work-supporting cradles at its ends remote from its axis, each cradle pro- .vided with two oppositely directed pivotally mounted work-supporting bars, means for adj ustably tilting each bar independently, means for clamping an end of a piece of work down upon a tiltable bar, an adjustable gauge plate co-operatively associated with the worksupporting bar, and a pair of face gauges hinged at their bottoms to fixed supports near the ends of the work and adapted to be swept in the arc of a circle 'over the front face of the work, forthe purposes set forth.

2. In a machine for face-grinding locomo-' tive guides and similar work, a turn table having upright work-supporting cradles at its ends remote from its axis, each cradle provided with two oppositely directed pivotally mounted Work-supporting bars, means for adj ustably tilting each bar independently, means for clamping an end of a piece of Work down upon a tiltable bar, and a pair of face gauges hinged at their bottoms to fixed supports near the ends of the work and adapted to be swept in the arc of circles in a plane 0 corresponding to the front face of the Work,

for the purposes set forth.

In testimony whereof, I affix my signature.

FREDERIG K. BENEDICT.

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