US2290611A - Swing frame grinder - Google Patents

Description

JMB/21, 1942. c. E. HITE 2,290,611

SWING yFRAME GRINDER Filed Oct. l2, 1940 2 Sheets-Sheet 1 ',{81 K i ,H8 j I C 474243 4% as LH July 21; 1942. E. Hm; 2,290,611

SWING FRAME GRINDER Filed Oct. 12, 1940 2 Sheets-'Sheet 2 l mw JWM/.62%g A Patented July 21, 1942 SWING FRAME GRINDER Charles E. Hite, Philadelphia, Pa., assigner to Albert P. De Sanno, Jr., Phoenixville, Pa.

Application October 12, 1940, Serial No. 360,924

15 Claims.

The present invention relates to swing frame grinders and to the swing suspension, to the operation and to the control of swing frame grinders. The term swing frame grinder in the specification and in the claims means a heavy duty grinder including a frame, a wheel mount and motor carried by the frame toward the forward and rearward ends thereof, a swing suspension support located between the mount and motor and an operating handle or handles extending forward longitudinally beyond the wheel mount for use in strongly pressing the wheel to the work, with the wheel journaled in its mount axially normally horizontal to grind normally on a hori- Zontal axis with endwise swinging of the generally horizontal grinder, the structure thus far described being of a type of heavy duty grinder Widely used in the prior art.

A purpose of the invention is to avoid shock between the wheel and work.

A further purpose is to resiliently cushion the wheel from inertiafrom that of other parts of the machine and from that of the operator` pressing upon the machine handles.

A further purpose is to use the weight of the machine in applying pressure between the wheel and work.

A further purpose is to adjustably limit the pressure between the wheel and work.

A further purpose is to continuously indicate the pressure between the wheel and work.

A further purpose is to use variation in pressure between the wheel and work to accomplish one or more or all of the following operations: to stop the motor before the wheel leaves the work; to start the motor after applying the wheel to the work; to sound an alarm whenever the working pressure becomes undesirably high or/and whenever it becomes undesirably low; to stop the motor whenever the working pressure rises above a set high limit or/and whenever it sinks below a set low limit, restarting the motor when the pressure reenters the set pressure range.

A further purpose is to sound high or/and low pressure alarms whenever the pressure is high or low respectively.

A further purpose is to stop the motor automatically whenever the wheel pressure departs from an adjustably predetermined range and to start the motor automatically whenever the wheel pressure reenters the range.

A further purpose is to swing support a swing frame grinder from longitudinally forward and rearward points when not grinding, and when grinding to swing support it at the rearward point while supporting its forward end on the work and wheel. 4

A further purpose is to raise and lower the front of the machine to and from the work while swing supporting the machine toward the rear.

A further purpose is to extend an arm rearwardly beyond the motor for swing support of the machine from points adjustably distant from the center of gravity of the machine.

A further purpose is to put part of the machine weight on and off the wheel while the wheel is presented to the work.

A further purpose is tov suspend the machine adjustably with respect to height from near opposite ends of a trolley rollable along a track, and optionally to pivotally support the track on a second trolley rollable along a second track, with the second track preferably movable laterally.

Further purposes will appear in the specification and in the claims.

I have elected to illustrate a few only of the different forms of my invention, illustrating forms however that are practical and efficient in operation and which well illustrate the principles involved.

The drawings are intended to be conventional and in a measure diagrammatic.

Figure 1 is a side elevation to show one embodiment of the invention.

Figure 2 is a broken top plan of Figure l, in part in section.

Figure 3 is a side elevation of another embodiment, omitting the motor and omitting an optional additional suspension element.

Figure 4 is a broken top plan of Figure 8.

Figure 5 is a broken elevation showing another v embodiment of some features of the invention.

Figure 6 is a side elevation of another embodiment.

Figure 7 is a detail section of Figure 6, taken upon the line 'l--1 thereof, but with the parts in somewhat diferent position. In Figure 6 the handles 263 are undepressed while in Figure 7 they are shown somewhat depressed against the upward retraction of the plate 55', bolt 54, spring 52 and plate 55 across the ends of the forward extensions 56 of the wheel mount.

Figure 8 is a top plan of Figure 6. Y Figures 9 and 10 are elevations, to enlarge scale, of alternative contact, indicator and control mechanisms, either being intended for use with any of the embodiments of the preceding to illustrate suspension features of the invention.

Figures 13 and 14 are sectional elevations of Figures 9 and 10, taken upon the lines l3-l3 and lli-I4 thereof respectively.

Like numerals refer to like parts in all figures.

Describing in illustration and not in limitation and referring tc the drawings:

Each of the illustrated swing grinders broadly is intended to include a grinding wheel l5, a motor l5, body structure H and one or more swing elements i8; and work upon which the grinding wheel operates is indicated at I9.

The motor is intended to drive the wheel in any suitable way-conveniently by belt drive-and with the revolution per minute wheel speed preferably selectively variant, either by the use of step pulleys or by a variable speed motor. This drive, where shown at all, is shown conventionally as motor and wheel pulleys 2l) and 2l and an intermediate belt 22. It will be understood that .the pulleys and 2l may be step pulleys.

In general, the body structure I' includes a wheel mount 23, 231, 232 or 233 and a supporting frame 24, 241, 242 or 223, the wheel mount hinging at 25, 251, 252 or 253 to the frame, hinging movement, between the mount and frame being resiliently resisted by means specific to the particular embodiment of the invention.

In general, the frame 24, 241, 242 or 243 supports the motor i6, is extended forward of the wheel to provide operating handles 25, 261, 262 or 253, receives one or more swing elements i8 and preferably is extended rearward of the motor to receive a rearward swing element I8 at a suitable eye 2 or 211 that is preferably adjustable longitudinally of the frame along a portion thereof rearward of the center of gravity of the machine. The forward swing element lil may be received by the frame at any suitable point thereof forward of, or even at, the center of gravity of the machine, and received either in an eye 28 (Figure l) rigid with the frame 24 or be received by an inward arm 2S of a shift lever 32 pivoting on a pin 5| rigid with the frame. (Figures 6 and 8.) In these figures the swing element i8 at its lower end hooks under an inward portion of the arm 29.

Referring to Figures 1 and 2, the motor l5, adjustable for belt tension adjustment, is located between adjustment screws 32and 35 for motor adjustment about a supporting pivot 34. The screws 32 and 33 thread lugs 35 of the frame structure, on a yoke portion 35 thereof upwardly embracing the motor and carrying the pivot pin 34. rThe pivot pin S4, located at a suitable distance below the motor, is intended to project from opposite sides of the yoke to receive spaced downwardly directed forks of a bracket 35 fastened to the motor. One only of these forks 35 is visible on the drawings.

The suspension eye 2l is intended to be adjustable along the length of a rod 3l' carried by upward arms 38 and 39 of the frame at portions thereof rearward and forward of the motor. Optionally the rod 3l and arms 38 and 39 may be omitted and the suspension eye 2'! carried on the frame portion 45 rearward of the motorbut the use of the long rod 31 across the motor permits wider adjustment of the eye 21 and thereby of the weight portion deliverable to the wheel and work when the machine is lowered at the forward eye 23 to present the wheel to the work.

The resilient resistance to hinging movement between the wheel mount 23 and the frame 24 in response to pressure between the wheel and work is applied between opposing upward arms 4l and 52 of the wheel mount and frame respectively and by a spring 43 adjustably compressed against the upper end of the frame arm 42 by a nut and washer 44 on an eye bolt 45 carried by the wheel mount arm 4l.

The eye bolt, surrounded by the spring 43, is carried on a pivot pin 4S in the suitably slotted top of the arm 4I and beyond the spring passes the slotted top of the arm 42, a nut 4l beyond the arm 42 adjustably limiting the retraction of the eye bolt and thereby of the wheel mount.

In Figures 3 and 4 the resilient resistance to hinging movement between the wheel mount 231 and the frame 241 is applied upon an upwardly directed surface of the frame by a at spring 48 carried by the wheel mount. The spring 48 is suitably fastened at |29 to the wheel mount and retraction of the wheel mount is limited by a rearward arm 5i] of the wheel mount coming against an under surface of the frame.

Sometimes, with special conditions 01 circumstances, a single suspension element I8 may be preferable to two suspension elements and in Figures 3 and 4 I have therefore shown but one suspension element l5 and with a conventional motor mount 5l rearwardly ending the frame 241. The mount 5| is intended for any suitable motor mount and it will be understood that the illustrated frames of other figures may omit rearward extension beyond the motor if used with single suspension.

In Figure 5 the resilient resistance to hinging movement between the wheel mount 232 and the frame 242 is applied between opposing upward arms 4| and 42 of the wheel mount and frame respectively and by a tension spring 43 adjustably tensed between a pivot pin 45 in the upper end of the arm 4i and an eye bolt 45 carried adjustably at 45 in the frame arm 42.

In Figures 6 and 8 the wheel mount 233, frame 223 and hinge 253 are effectively an integral unit, the hinge 253 comprising a transverse strip of resilient metal connecting the mount and frame members 233 and 243.

The hinge 253, whether an insert welded or otherwise fastened to both members 233 and 243 or a reduced thickness portion of a single casting making all three members 233, 243 and 253, it should be dimensioned for the intended servicefor the needed small resilient bending while presenting all or a portion only of the resilient resistance to the hinging movement.

In the illustration, an adjustable portion of the resilient resistance to hinging movement is intended to be carried by a spring 52 adjustably compressed between a nut 53 on a bolt 54 supported by the frame and the upward surface of a plate 55 carried by the wheel mount 233 across the forwardly extended ends 56 thereof.

The bolt 54 is supported from upward movement with respect to the frame by a plate 55' below and across the handles 253 of the frame, optionally dimensionally the same as the plate 55 which is extended to overlap the handles 263 to limit downward retraction of the wheel mount.

The wheel mount 233 is intended to carry the upper half of split bearings of the wheel unit and also to carry suitable cover and shield structures, not shown, of the wheel and pulley. The wheel unit is intended to be removable downwardly by the removal of the lower half 51 of the split bearings of the unit.

The shift lever 30 adapted to slightly raise and lower the frame at 29 to respectively release and apply weight of the machine to the wheel and work, presents a down-bend handle and latch 58 adjacent one of the operating handles 263.

The shift lever is shown in its weight applying position. The weight is released from the wheel and work by an upward shifting of the down-bend handle 58 to latch over the handle 263 (Figure 7) after riding the inwardly sloping edge 59 of the down-bend along the outer edge of the member 263.

-A counterbalance spring 68 is intended to balance the lever 3D for easy operation, counterbalancing the weight of the lever and of the machine to any desired extent, the spring 69 being adjustably compressed between the frame 243 and a nut 6| on a bolt 62 carried by a, suitable inward lug from the lever 39, the lug being indicated in dot at 63 and the bolt 62 extending upwardly therefrom loosely through the frame.

The motor I6 is carried on a composite member 64, 65, 66, 61 intended to be suitably bolted to the motor at intervals about the driving end thereof.

The motor mount 64, E5, 66, 61 shields or covers the motor pulley at 64, extends downward at 65 to pivot at 66 in a low lug 68 of the frame 243 and extends upward at 61 to receive adjustable resilient support for the pull of the motor belt 22. The resilient support for the pull of the belt is provided by a spring 69 compressed adjustably against an upward arm 19 of the frame 243 by a nut 1| on a threaded eye bolt 12 that is pivotally carried at 13 in the arm 61 of the motor mount, is surrounded by and positions the spring 69 and beyond the spring passes through a suitable slot or bore of the arm 18.

In general, rod and panel members a and b have been shown on the embodiments thus far described. These members are mounted for relative movement responsive to relative movement of the wheel mount 23, 231-232 or 233 and frame 24, 241, 242 or 243 and are intended for la conventional showing of any suitable mechanism using variation in pressure between the wheel and work to accomplish one or more or all of the following operations: to deenergize the motor before the wheel leaves the work; to energize the motor after applying the wheel to the work; to sound an alarm whenever the working pressure becomes undesirably high or/and whenever it becomes undesirably low; to deenergize the motor whenever the working pressure rises above a preset high limit or/ and whenever it sinks below a preset low limit; to reenergize the motor when the working pressure reenters a preset pressure range.

In Figure l the rod a pivoted at c on a rearward extension d of the frame arm 42, an upward extension from the frame 24, is presented by gravity or by a suitable spring not shown to the rear end of the eye bolt 45 from the wheel mount 23 for movement thereby across the panel b mounted on the frame structure.

In Figures 3 and 4 and also in Figure 5 the panel b is mounted on the forward end of the wheel mount 231 or 232, is slotted across its width at e for easy resilient bending and provided with a resilient bias to maintain it in cooperating relation with the rod a mounted on one of the handles 26. The contact members a and b` are in sliding contact, maintained resiliently at e and are fastened respectively to the frame 241 or 242 and to the wheel mount 231 or 232, the spring 43 or 43 resisting deflection between the frame and vmount members 241 or 242 and 231 or 232.

In Figures 6 and 8 the-members a and b, intended to be preferably located between the plates 55 and 55 have been shown immediately forward thereof, with the panel b mounted on one or both of the rearward wheelmount extensions 56 and the rod a mounted on one of the handles 261 or 262. The contact member a is thus shown fastened to the frame member 243 from one of the arms 263 with the contact member b fastened to the wheel mount 233 across the ends of the arms 56.

I have illustrated two embodiments only of the cooperating rod and panel mechanisms a and b, in Figures 9 and l0 respectively. An electric grounding circuit f, g shown applied to the rod and panel mechanisms ai or a2 and bi or b2 in Figures 9 and 10` is intended for a conventional showing of any circuit adapted to control the operation of thev motor I6 or/and that of an electric alarm h. The composite rod and panel members a1 or a2 andbi or b2 are intended to be supported respectively at i and i, suitable portions of the machine respectively on the resiliently connected wheel mount and frame and thereby relatively movable in response to changing pressure between the wheel and work transmitted through the wheel and its resilient connection with the frame and transmitted resiliently between the frame and work.

In the illustrations of Figures 1 to 8 the cooperating Contact members a and b are carried cooperatively by the mount and frame members 23 and 24, with the members a and b resiliently in sliding contact one with the other and in relative positions determinatively responsive to the pressure between the wheel and work, and any of many mechanisms may be carried cooperatively by the members a and b, suitably the pointer-and- scale indicator 83, 16 or 83', 16 of Figure 9 or of Figure 10.

In Figure 9, the composite rod mechanism ai, suitably supported from the machine at i, includes a fiat spring 14 at or near its supported end and an arm 15 therefrom preferably of insulation material. The arm 15 carries at intervals of its length an indicator 16, adjustable screw contacts 11, 18, 19, and 8| 4and the electric signal h.

The composite panel b1, suitably supported at y', comprises an insulation plate 82, a scale 83 and a contact plate 84.

The scale 83 and contact plate 84 are adjustably fastened at 85 and 86 respectively to the plate 82, respectively to present the scale 83 in best cooperative relation with the indicator 16 and contact surfaces 81, 88, 89, 96 and 9| in best cooperative relation with the inwardly directed ends of the screw adjustment contacts 11, 18, 19, 80 and 8| respectively. Only the insulation heads of the screw contacts 11 to 8| a-re visible in the drawing; their inwardly directed contact ends are presented inward to extents individually adjustable at the insulation heads .of the contacts.

Of the contact surfaces 81 to 9|, the surface 9| is intended to be parallel to the direction of movement of the panel b1 and during the desired range of pressure between the wheel and work the normal operating circuit is closed through the members f, 8|, 9|, g.

The surfaces 89 and 98 slope in reverse directions with respect to the direction of movement of the panel b1 to cooperate with the signal cir- .cuit contacts 19 and 80 and these screw contacts 19 and 80 are adjusted to engage their respective cooperating surfaces 89 and 901 at any desired wheel pressures.

With rising wheel pressure above any preset limit the wedge surface 89 engaging the screw contact 19 deflects the arm 15 outward against the retraction of the spring 14, opening the normal motor control circuit f, 8|, 9|, g operating the high pressure signal through the signal and motor control circuit f, h, 19, 89, 9|, g. If in response to the lsignal the Wheel pressure is reduced to the preset range the arm 15 retracts inward until stopped by the screw contact 8| engaging the contact surface 9|, closing the normal motor control circuit f, 8|, 9|, g and then with further reduction of wheel pressure opening the circuit f, h, 19, 89, 9|, g in that the wedge 89 is then in a position at which it cannot engage the contact 19.

The operation of the low pressure signal is eX- actly similar, the low pressure signal operating through the signal and motor control cir-cuit f, h, 80, 99, 9|, g as soon as the wheel pressure sinks below any preset low limit.

In similar manner deenergizing the motor may be effected automatically at any desired high and low limits of wheel pressure by suitably adjusting the screw contacts 11 and 18 with respect to their cooperating reverse wedge contacts 81 and 88 which are suitably steeper than the wedge contacts 89 and 99. Adjustments are conveniently effected while applying the high and low limit pressures beyond which it is deemed undesirable for the motor to operate.

In Figure 10 the rod a2 comprises a resilient f1 conductor 15', an adjustable screw contact 8| and an indicator 16', and the panel b2 comprises an insulation base plate 82', the signal h, the scale 83', adjustable high and low pressure wedge signal contacts 89' and 99' and adjustable high and low pressure cut-out wedges 81' and 88 that are suitably steeper than the contacts 89' and 98.

In normal operation the screw contact 8|' is presented to the non-sloping contact 9|' closing a, motor control circuit f, 9|', 8|', 15', g. The high pressure signal operates when with rising wheel pressure the wedge contact 89 engages tlie resilient conductor 15' wedging it outward to open the motor control circuit f, 9|', 8|', 15', g while closing the signal circuit f, h, 89', 15', g which with further rise of wheel pressure will be opened at any desired point by the suitably set steeper wedge 81. The low pressure signal and the low pressure cut-out are effected in similar and obvious manner by means of the low pressure signal contact 9U' and the steeper low pressure cut-out contact 88'.

In Figures l and 2 relative movement of the members a and b is multiplied by lever structure while in each of Figures 3, 4, 5 and 6, 8 the members a and b are fastened one to the wheel mount 231, 232 or 233 and the other to the frame 241, 242 or 243. In Figures 9 and 10 the members ai and b1 and a2 and b2 are shown carried cooperatively between the frame and mount by conventionally shown structures i and 7', intended to be any suitable structures between the frame and mount. In Figures 1 and 2 i may be considered as the upper portion of the member a responsively connected to the wheel mount 23 through the eyebolt 45 while j may be a suitable Iextension from or portion of the frame 24. In each of Figures 3, 4, 5 and 6, 8 the structures i and y are portions one of the wheelmount 231, 232 or 233 and the otherof the frame '241, 242 or 243.

I illustrate in Figures l1 and 12 too only of the suitable overhead supporting structures of the grinder.

The grinder depends on the suspension elements I8 and I8 from near opposite ends of a suitable trolley 92 or 92' and with hoists 93 and 93' directly beneath the trolley permitting the grinder to be raised and lowered easily and to any desired extent at points forward and rearward of the center of gravity of the grinder.

In Figure 11 the forward suspension element is intended to have been located but a little forward of the center o f gravity of the machine to shorten the spacing between the suspension elements with a resultant lessening of the needed length of the trolley 92. In many cases however it may be desirable to locate the forward suspension element well forward in order to bring the hoist 93 near to the operating end of the machine.

In Figure 12 the trolley 92' is shown rollably supported on a track 94', suitably of I-beam section and either stationary or laterally movable according to operating requirements.

The overhead structure of Figure 1l provides for universal shifting of the machine for operation anywhere over a relatively wide floor space. The short track 94 supporting the trolley 92 is provided with end guards 95 and is provided with vertical pivot support at 9B from the bottom of a second trolley 91 that is supported by and rollable along a second. track 98.

The second track 98 is intended to be movable laterally, as indicated by the arrow.

It has been found that grinding economy is materially dependent upon the use of right pressures between the wheel and work and these vary both with the character of the work and the character of the wheel, as to grade and material from which the work has been made, and my invention, particularly in its features eliminating wheel shock, in disclosing the operating pressure, in signaling any departure from predetermined right pressure ranges and in deenergizing the wheel when this departure is too great, should result in great economies in grinding.

In view of my invention and disclosure variations and modifications will doubtless become evident to others skilled in the art either to meet individual whim or particular circumstance and I claim all such in so far as they fall within the reasonable spirit and scope of the invention.

In the structure of Figures l and 2 the member 39, 31, 38 is intended to comprise a yoke rotatable at 38 and v39' on the frame to permit easy angular vertical turning of the grinder for operation of the grinder with the wheel at different angles to the vertical.

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

1. A swing frame grinder, elongated, operating generally horizontal, having intermediate its length a swing support to adapt it to back and forth grinding travel in direction of its length and laterally thereof, and the grinder comprising an elongated forwardly and rearwardly directed frame, a motor on the frame toward its rearward end, a grinding wheel operable by the motor and located toward the forward end of the frame, a wheel mount journaling the wheel, a hinge connection between the mount and frame with the line of hinging located rearwardly of the wheel axis, an upward arm on the mount from the line of hinging, an upward arm on the frame opposing the first arm and spaced therefrom in the direction of the frame length and a resilient connection between the arms at opposing upper portions thereof permitting sudden vertical resilient movements between the wheel and frame during grinding.

2. A swing frame grinder, elongated, operating generally horizontal, having intermediate its length a swing support to adapt it to back and forth grinding travel in direction of its length and laterally thereof and the grinder comprising an elongated forwardly and rearwardly directed frame, a motor on the frame toward its rearward end, a grinding wheel operable by the motor and located toward the forward end of the frame, a wheel mount journaling the wheel, a resilient supporting connection between the frame and mount permitting sudden vertical resilient movements between the wheel and frame and means effective towards the forward end of the frame for downwardly pressing the frame to press the wheel to the work through the resilience of the said connection and means for adjusting the resilience between the wheel mount and frame.

3. A swing frame grinder, elongated, operating generally horizontal, having intermediate its length a swing support to adapt it to back and forth grinding travel in direction of its length and laterally thereof and the grinder comprising an elongated forwardly and rearwardly directed frame, a motor on the frame toward its rearward end, a grinding wheel operable by the motor and located toward the forward end of the frame, a wheel mount journaling the wheel, a resilient supporting connection between the frame and mount permitting sudden vertical resilient movements between the wheel and frame and means effective towards the forward end of the frame for downwardly pressing the frame to press the wheel to the work through the resilience of the said connection and an indicator operated by the mount and frame to show the relative positions thereof and thereby the pressure between the wheel and work.

4. A swing frame grinder, elongated, operating generally horizontal, having intermediate its length a swing support to adapt it to back and forth grinding travel in direction of its length and laterally thereof and the grinder comprising y an elongated forwardly and rearwardly directed frame, a motor on the frame toward its rearward end, a grinding wheel operable by the motor and located toward the forward end of the frame', a

wheelmount journaling the wheel, a resilient supporting connection between the frame and mount permitting sudden vertical resilient movements between the wheel and frame and means effective towards the forward end of the frame for downwardly pressing the frame to press the wheel to the work through the resilience of the said connection and the grinder having a determinative electric circuit and having switch contacts thereof operated by the mount and frame in order to determine the condition of the circuit by the relative positions of the mount and frame and thereby according to the pressure between the wheel and work.

5. A swing frame grinder, elongated, operating generally horizontal, having intermediate its length a swing support to adapt it to back and forth grinding travel in direction of its length and laterally thereof and the grinder comprising an elongated forwardly and rearwardly directed frame, a motor on the frame toward its rearward end, a grinding wheel operable by the motor and located toward the forward end of the frame, a wheel mount journaling the wheel, a resilient supporting connection between the frame and mount permitting sudden vertical resilient movements between the wheel and frame and means effective towards the forward end of` the frame for downwardly pressing the frame to press the wheel to the work through the resilience of the said connection, a signal, an electric circuit to operate the signal and a switch of the circuit operatively connected to the mount and frame to operate the signal by the position of the frame with respect to the mount and thereby according to the pressure between the wheel and work.

6. A swing frame grinder, elongated, operating generally horizontal, having intermediate its length a swing support to adapt it to back and forth grinding travel in direction of its length and laterally thereof and the grinder comprising' an elongated forwardly and rearwardly directed frame, a motor on the frame toward its rearward end, a grinding wheel operable by the motor and located toward the forward end' of the frame, a wheel mount journaling the wheel, a resilient supporting connection between the frame and mount permitting sudden vertical resilient movements between the wheel and frame and means effective towards the forward end of the frame for downwardly pressing the frame to -press the wheel to the work through the resilience of the said connection and means operatively connected to the mount and frame for energizing and de-energizing the wheel according to the position of the frame with respect the mount and thereby according to the pressure between the wheel and work.

7. A swing frame grinder, elongated, operating generally horizontal, having intermediate its length a swing support to adapt it to back and forth grinding travel in direction of its length and laterally thereof and the grinder comprising an elongated forwardly and rearwardly directed frame, a motor on the frame toward its rearward end, a grinding wheel operable by the motor and located toward the forward end of the frame, a wheel mount journaling the wheel, a resilient supporting connection between the frame and mount permitting sudden vertical resilient movements between the wheel and frame and means effective towards the forward end of the fraine for downwardly pressing the frame to press the wheel to thework through the resilience of the said connection, an electric circuit energizing the wheel and wedge-adjustable-means operatively connected to the mount and frame for opening and closing the circuit according to the adjustably selective position of the frame with respect to the mount and thereby according to the adjustably selective pressure between the wheel and work.r

8. A swing frame grinder, elongated, operating generally horizontal, having intermediate its length a swing support to adapt it to back and forth grinding travel in direction of its length and laterally thereof and the grinder comprising an elongated forwardly and rearwardly directed frame, a motor on the frame toward its rearward end, a grinding wheel operable by the motor and located toward the forward end of the frame. a wheel mount journaling the wheel, a resilient supporting connection between the frame and mount permitting sudden Vertical resilient movements between the wheel and frame and means effective towards the forward end of the frame for downwardly pressing the frame to press the wheel to the work through the resilience of the said connection, an electric circuit energizing the wheel and wedge-means operatively connected to the mount and frame for opening and closing the circuit according to the position of the frame with respect to the mount and thereby according to the pressure between the wheel and work.

9. A swing frame grinder, elongated, operating generally horizontal, having intermediate its length a swing support to adapt it to back and forth grinding travel in direction of its length and laterally thereof and the grinder comprising an elongated forwardly and rearwardly directed frame, a motor on the frame toward its rearward end, a grinding wheel operable by the motor and located toward the forward end of the frame, a wheel mount journaling the wheel, a resilient supporting connection between the frame and mount permitting sudden vertical resilient moVements between the wheel and frame and means effective towards the forward end of the frame for downwardly pressing the frame to press the wheel to the work through the resilience of the said connection, an electric circuit to energize the wheel and reversely sloping wedge means operatively connected to the mount and frame to operate the'opening and closing of the circuit at low positions of the frame with respect to the mount by means of one wedge and at high positions of the frame with respect to the mount to operate the opening and closing of the circuit by means of a reversely sloping wedge, thereby to maintain the wheel energized as long as the pressure between the wheel and work is between high and low pressure limits determined by the said means and de-energized when the pressure between the wheel and work is above the high limit and de-energized when the pressure between the wheel and work is below the low limit.

10. A swing frame grinder comprising an elongated generally horizontal forwardly and rearwardly directed frame, a motor on the frame toward the rearward end thereof, a grinding wheel operable by the motor, a handle forwardly of the wheel for downwardly pressing and forwardly and rearwardly moving the wheel on the work, a suspension element from a portion of the grinder located along the grinder at or forward of the center of gravity of the grinder and for use during periods of non-grinding and a second suspension element from a portion of the grinder rearward of the center of gravity, for use during grinding periods with the first element then inoperative and the weight of the machine i.;

supported between the work and rearward element, making part of the machine weight effective for grinding pressure between the wheel and work and means operable at the handle for shifting the machine vertically at one of the suspension elements to raise and lower the wheel from and to the work.

11. In a swing frame grinder, a suspension element located adjustably rearward of the center of gravity of the grinder and a second suspension element atV or forward of the center of gravity whereby when not grinding the weight of the machine is supported normally on the two suspension elements and whereby during periods of grinding the weight of the machine may be carried between the work and a suspension element located adjustably to the rear of the center of gravity, thereby making an adjustable portion of the weight effective for grinding pressure between the wheel and work.

12. In a swing frame grinder, a wheel mount, a frame, a resilient connection between the mount and frame and suspension elements located at pointson the Vframe respectively rearward of and at or forward of the centerof gravity of the grinder whereby when not grinding the weight of the machine is supported normally on the two suspension elements and whereby during periods of grinding the weight of the` machine may be carried between the work and rearward suspension element making a portion of the weight of the machine effective for grinding pressure and whereby the resilience between the wheel and frame cushions the greater inertia of the machine from the wheel, the machine inertiaincreasing with increasing distance of the rearward suspension element from the center of gravity of the machine.

13. In a swing frame grinder, a wheel mount, a frame, a resilient connection between the mount and frame, an operating handle, suspension elements on the frame located at points thereof respectively rearward of and at or forward of the center of gravity of the grinder and means operable at the handle and adapted to slightly raise and lower the ginder at the forward suspension element to raise and lower the wheel to the work, whereby when the wheel is lowered to the work the machine weight is carried between the work and rearward suspension element making a portion of the machine weight effective for grinding pressure, and whereby when the wheel is raised the weight of the machine is carried between the two suspension elements.

14. A swing frame grinder comprising an elongated forwardly and rearwardly directed frame, a motor on the frame toward the rearward end thereof, a grinding wheel operable by the motor and located toward the forward end of the frame, a handle forwardly of the wheel for downwardly pressing and forwardly and rearwardly moving the wheel on the work, a forwardly and rearwardly directed arm located above and across the motor and downwardly connected with the frame, and a suspension element adjustable along the arm, adapting the grinder toward its forward end supported on the wheel and work to be moved at the handle back and forth in direction of the grinder length and laterally thereof with an adjustable portion of the weight of the machine effective for pressure between the wheel and work.

15. A swing frame grinder comprising an elongated forwardly and rearwardly directed frame, a motor on the frame toward the rearward end thereof, a grinding wheel operable by the motor and located toward the forward end of the frame, a handle forwardly of the wheel for downwardly pressing and forwardly and rearwardly progressing the wheel on the work, a yoke downwardly embracing the motor, having downward arms respectively forward and rearward of the motor, coaxial pivot connections between the downward arms and frame to provide an axial pivot support fror the machine during grinding and a suspension element on the yoke, whereby during grinding the weight of the machine is carried between the work and suspension element, making the weight portion on the work effective for grinding pressure and whereby the machine may be angularly turned in the pivot between the frame and yoke to apply the wheel at an angle to the vertical.

CHARLES E1. HITE.

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