US1923760A

US1923760A - Grinding machine

Info

Publication number: US1923760A
Application number: US578858A
Authority: US
Inventors: John A Smith
Original assignee: United States Electrical Tool Co
Current assignee: United States Electrical Tool Co
Priority date: 1931-12-04
Filing date: 1931-12-04
Publication date: 1933-08-22
Anticipated expiration: 1950-08-22

Description

9 22, 1933- J. A. SMITH 1,923,760

GRINDING MACHINE Filed Dec. 4, 1931 3 Sheets-Sheet 1 INVENTOR ATTORNEY? g- 22, 1933- J. A. SMITH 1,923,760

GRINDING MACHINE Filed Dec. 4, 1951 3 Sheets-Sheet 2 NVENTOR ATTORNEYf Aug. 22, 1933. J. A. SMITH 1,923,760

GRINDING MACHINE Filed Dec. 4, 1931 3 Sheets-Sheet 5 d INVENTOR a M ATTORNEYJ' GRINDING MAQHENE Beceinlier 4, 1%31.

l improved speed olianc e.ing wneels is, therefore, an oejet this inve ion to hange niec .liSiil for power opel-tat a variety of 01 01 shif t ineans lSiJ Will the guards 1. provide an which is convenien ly o'- of the gr iding speeds and to connect the for this speed change me surrounding the grindin speed cannot be instance is movable towa because of reduction in grinding wheel as soon by W The guards surround the the diameter of the grin due to wear, the ma the same at provi rng a co. Us nection to the connection f i sion control wherein the may he aninulated go.

It a further obj ct to provide a shif roved for use in s .ing ies independently of imposed by the connection to i s the guard in each "inding wheel terof the or otherwise.

ing Wheels and a1 its :ol condue to niechanieal d the mi ssio' at to provide'an extremely novel mechanical co trol connection between the gu lilting carat-us wherein the sterlocl; for compellii speeds proportionate to the of the grinding wheels is effected.

accompanying ure 1 a machine ments.

Figure removed,

ieels so that higherare fixed to the grind ransiniscontrol and o'oerating means therefor and the control connec on to one guards. Figure 3 is a sectional View taken on line 3-3, Figure 2, further illustrating the speed change apparatus. I

Figure i is a sectional view taken on line 44=, Figure 3, illustrating the -mounting for the motor and a portion of the gear operating means. Figure 5 is an end View of the grinding machine showing the mechanical connection between the speed change operating and the guard for compulsory proportion of the grinding wheel speeds relative to the diameter thereof.

The particular style or type of grinder herein illustrated includes a hollow base or machine casing 1 having bearings 2 mounted in alignment at its respective ends. A grinding wheel shaft 3 is-mounted in these hearings and extends from the ends of the base or frame, the grinding wheels being fixed thereto at the respective ends. The bearings 2 are separate elements bolted upon ledges or lugs l of the grinder frame at the respective ends.

Each grinding wheel includes a sectional guard attached thereahout. A. cluster of gears 5 e Wheel shaft within the frame, these gears var ing in size'clepending on the particular speeds incorporated. The electric ported for rocking movement on a stationary shaft 8 fixed. between the respective end walls of the base toward the rear thereof. 'The stub shaft 9 of the motor carries a pinion 10 at the end adjacent the gear cluster, this pinion adapted to mesh with any one of the series of gears'in the cluster; meshing eing accomplished by shifting the motor and its-base on the support shaft longitudinally thereof, and rocking or permitting rocking of the motor and lease on "the shaft to bring the pinion into mesh with the adjacent'g'ear of the series, the speed changetherefore depending on the extent of the longitudinal shift.

The centers of the motor support shaft 8, motor stub shaft 9, and grinding wheel drive shaft 3 are so related th pinion is of a size properly determined relative to the diameter ofthe largest gear of the cluster whereby mesh between the pinion and any of the gears of the series is maintained by gravity at all times as imposed by the weight of the motor unit, the motor unit being side of the motor by means of a bracket 11 these stops adapted to successively cooperate with a fixed stop 12 attached to the forward wall of the hollow base or machine casing 1.

The stops 11 and 12 in each instance consist of screws engaged into the base of the motor or the frame as the case may be and maintained in adjusted position by means of nuts 13. The stop screws on the motor base have their heads disposed at successively greater distances from the frame, the variation in the positions of the heads being determined by the difference of the diameter of the gears on the grinding wheel drive shaft.

There are four of these stop screws in this instance, thereby accommodating for four speed change gears 5. As will be apparent from Figure 2, the stop screw protruding the greatest distance from the motor base is in engagement with the stationary stop 12 on the frame at the time when the pinion 10 is in mesh with the largest gear of the cluster. When the motor and pinion have been longitudinally shifted for swinging movement to engagement with the smallest gear of the cluster, the shortest stop screw 11 rests againstthe stop screw 12 of the frame with the corresponding positions between being apparent from the step relation of the stops 11 as shown in Figure 2 of the drawings.

The machine frame includes a cover section 1 which can be swung back for access to the motor unit and th gears as well as the other operative parts of the gear shifting means.

In view of the movements necessary for shifting of the pinion into mesh with a particular gear of the series, there are two control levers provided for this purpose, oneof these control levers, namely 14, causing swinging movement of the motor on the stationary rock shaft or releasing the same for swinging movement and the other, namely 15, accomplishing translation of the motor and pinion on the motor support shaft. In the instance of the first control lever 14, the lever extends through an aperture 14' in the front of the frame and presents a pedal or treadle portion 16 at the front of the machine which the operator may conveniently operate with his foot.

The rear end of this treadle lever 14 is'pivoted to the back of the frame on a lug 17 thereof by means of a pin 18, and a link 19 is pivoted to the lever 14 by means of a pin 20 forwardly of the rear pivot of the treadle lever. This link carries a roller 21 on its upper end, the roller being loosely rotatably mounted thereon and having its periphery provided with a semicircular peripheral groove after the fashion of a cable roller, this roller engaging upon a stationary rod 22 fixed in and between arms 23 which extend from the motor base radially relative to the axis on which the base rocks. Therefore, as the treadle is depressed a swinging movement is imparted at the motor base and motor by the en gagement of the roller 21 with the rod. Due to the length of the rod the motor base is free to be moved longitudinally on its support shaft without disturbing the arrangement of parts for the aforesaid swinging movement,

In the instance of the translative means for the motor, the lever 15 is provided at the forward -f face of the machine adjacent the treadle, this lever being mounted on an operating shaft 24 journalled in the front of the frame and in bracket 25 affixed to the back of the frame. The control lever is hand operated and is therefore of considerable length for leverage purposes,

A detent 26 is mounted intermediate the length of the lever 15 and cooperates with a series of apertures 27 arranged in spaced relation in an arcuate or semicircular boss 28 cast on the front of the frame concentrically of the control shaft.

A gear 29 is fixed to the control shaft at the front of the rear bracket 25 thereof and is in mesh with a rack 39 slidably mounted on the pivot or motor support shaft 8 between the lugs 7 of the base 7, the base through this arrangement being rotatable on the shaft 8 relative to the rack 30 and being engaged by the rack for translation thereof in either direction. Plates 30 are attached to the respective sides of the rack, these plates overhanging the sides of the gear 29 and thereby maintaining the rack against rotation. Therefore, rotation of the control shaft by means of the lever 15 accomplishes translation of the motor and pinion and the apertures and cooperating detent determine the definite positions at which the transiative movement is effective for disposing the pinion in the proper meshing alignment with each of the particular gears of the cluster.

In performing any one of the series of shifts or speed changes, the operator must first depress the treadle by stepping on the same. The movement of the lever through its connection to the rear end of the motor base rocks the motor unit on its support and moves it from a position of mesh which is slightly forward or out of balance to a position toward the rear where it is substantially balanced, the motor shaft being in vertical alignment with the pivot shaft.

Normally when the gears and the pinion are in mesh with any one of the series of gears, the meshed position is maintained by gravity. For assisting the action of gravity, springs 31 are attached between the ends of the rod 22 and bolts or studs 32 fixed to the rear wall of the casing above the rod, these springs acting to swing the motor unit forwardly at all times. The slot 14 in the forward wall through which the treadle the pinion out of mesh with. any of the gears and the treadle lever is held in neutral position.

With the lever fully depressed, either maintained within the slot by the spring 14 or held down by foot pressure, the operator then manipulates the hand lever 1.5 for translating the motor unit on its support rod and accurately positions the pinion by cooperation of the detent in the shift lever with one of the apertures in the wall of the casing. Jhen the given position is attained, the operator then releases the treadle lever and the springs and gravity act to swing the motor unit on its pivot meshthe pinion with the selected gear, the stops governing or limiting the pressure of gear engagement and causing proper pitch line mesh.

The drive of the motor is anticlockwise as viewed in Figure 3 and therefore the thrust of the pinion on the particular gear tends to urge the gears together and stabilizes the gears in meshed position, this preventing any chattering.

The gear shifting apparatus above described is fully controlled by means of a mechanical connection extending to the grinding wheelgu'ards 33 of the machine. Inasmuch as this mechanical connection is duplicated at each end of the machine or may be at one end only, its'description will be led to a single end of the machine.

For the purpose of the connection, a shaft 34 is mounted n the rear end of the machine longitudinally L161 eof, this shaft having a bevel gear 5 pinned thereto and in mesh with-a bevel gear 5 pinned to the extreme inner end of the operating shaft 24 of the motor unit translating means. The outer end'of this longitudinal shaft 34 carrice an arm 37 and the upper end of the arm has a belt or pin therein engaged in the slot 39 of a link 40. The link has the slot thereof disposed toward one end and the opposite end of the link is pivotally to the lower end of a rod or bar ll which rigidly attached to the guard by a plurality of bolts 42 or other attaching means. To assure uniform resetting movement of the work rest 43 and the guard, a link is connects an intermediate point of the fixed bar 43. to the work rest through pin connections. The rest is adiustaoly mounted the forward. end of the grinding wheel guard for movement toward and from the periphery of the wheel at the point where the guard is open for the application of the work to the grinding wheel. 7 1

The particular construction of the guardand work rest is immaterial to the present case beyond the fact that the parts 41 and 4% maybe eadily conrected thereto for the result hori o. 1g of the guard and work rest toward and from the grinding wheel is effective fornioving the bar fixed thereto and resetting the slotted safety link.

As will be apparent from the end view of the I machine, the saf ty link functions for limiting movement 0; the arm 37 and the longitudinal shaft 34. and consequently the motor unit translating means. Initially, when the pinion 9 of the motor is in mesh with the largest gear for the lowest speed of the machine, the safety link is maintained in the position shown in the drawings because of the general position of the grinding wheel guard relative to the wheel. As resetting of the guard occurs, the safety link is moved rearwardly sliding on the pin or bolt 38 of the tion of the guard therefore restrains and controls the shifting operations.

The power transmission and speed change mechanism as set forth comprise a highly efficient form of drive which operates smoothly and in which the gear changes are conveniently made.

' The interconnection between the guards and the transmission fully and positively prevents the application of improper speeds to the grinding wheel and the operator is assured that the speed at which he is operating is in keeping with the diameter of the grinding wheel.

Having described my invention, I claim:

.L. In a grinding machine, a shaft, a grinding wheel mounted on said shaft, a translatable elemerit movable toward and from the periphery of said grinding wheel, speed change gears for said a motor unit pivotally and translatively mounted,

a pinion driven by said motor unit and carried thereby, means for translating saidmotor unit for disposing saidpinion opposite particular gear to be meshed therewith, and means for moving the motor. unit on itspivot for moving the pinionin and out of mesh with theadjacent gear of the cluster. Y i I 3. In a grindingmachinea shaft, a grinding wheel mounted-on said. shaft, a translatable ele ment movable toward and from the periphery of said grinding wheel, a series of gears of ent sizes fixed on said shaft, a power driven pinion adapted to be meshed with any gear of the series, a lever forshifting the pinion into position for mesh, a. control shafthaving transmission connection with said lever, an arm on said control shaft, a link pivoted to said translatable element, said link including a slotted outer end and a pincarried by said arm translatablyene gaged in said slot, whereby the position of "said pin in said siotcontrols the movement of said pinion shifting lever. I

A. In a grinding machine, a shaft, a grinding wheel mounted on said shaft, a translatable element movable toward and from the periphery of said grinding wheel, a series of gears of different sizes fixed on said shaft, a power driven pinion adapted to be meshed with any gear of the series, a lever for shifting the pinion into position of mesh, and a control means connecting said lever to said translatable element for governing the operation of said lever.

5. In a grinding machine, a shaft, a grinding wheel mounted on said shaft, a gear cluster composed of gears of different sizes fixed to said shaft, 2. motor unit, a shaft pivotally and translatively mounting said motor. unit, a pinion driven by the motor, a rack longitudinally disposed on said motor unit,- a gear engaging said rack, a shaft carrying said gear, a lever fixed on said shaft for rotating said shaft and translating said motor unit for disposing said pinion in position opposite a particular one of said gears, means for maintaining said lever in said position, said motor unit pivot shaft disposed relative to the grinding wheel shaft whereby the motor unit is unbalanced toward the gear cluster when the pinion is meshed with-any one of the gears, stops limiting gravity induced movement of the motor unit in each of the gear mesh positions for governing the pressure of gear mesh, a rod mounted longitudinally of andon the motor unit at the rear thereof, a roller engaged on said rod, a treadle lever extending to the front of the machine, a link connecting said treadle to said roller whereby depression of the treadle moves the pinion from meshed position, an abutment on the frame of the machine adapted to be engaged by said treadle lever when depressed when the pinion is unmeshed for maintaining the gears in neutral position, and springs normally urging the motor unit toward the, gear cluster; 7

6. In a grinding machine, a shaft, a grinding wheel mounted on said shaft, gears of different sizes fixed to said shaft, a motor unit, a shaft pivotally and translatively mounting said motor unit, a pinion driven by the motor, a lever and connection for translating said motor unit for disposing said pinion in positions opposite any one of said gears, said motor unit pivot shaft disposed relative to the grinding wheel shaft whereby the motor unit is unbalanced toward the gear cluster when the pinion is meshed with a particular gear, stops limiting gravity induced movement of the motor unit in each of the gear mesh positions for governing the pressure of gear mesh, and a treadle lever and connection to said motor unit, whereby depression of the treadle moves the pinion from meshed position,

7. In a grinding machine, a shaft, a grinding wheel mounted on said shaft, gears of different sizes fixed to said shaft, a motor unit, a shaft pivotally and translatively mounting said motor unit, a pinion driven by the motor, means for translating said motor unit for disposing said pinion in positions opposite any one of said gears, said motorunit pivot shaft disposed relative to the grinding wheel shaft whereby the motor unit is unbalanced toward the gear cluster when the pinion is meshed with a particular gear, and means for swinging the motor unit and pinion away from the gear cluster.

8. In a grinding machine, a shaft, a grinding wheel mounted on said shaft, gears of different sizes fixed to said shaft, a motor unit, a shaft pivotally and translatively mounting said motor unit, a pinion driven by the motor, means for translating said motor unit for disposing said pinion in positions opposite any one of said gears, means for urging said motor and pinion toward said gears for meshing of the pinion and the particular gear, and means for swinging the motor unit and pinion away from the gear cluster.

9, In a grinding machine, a grinding wheel shaft, a series of gears of different diameters mounted on said shaft, a motor unit including a pinion, a pivotal mounting means for said motor unit, means for rocking said motor unit toward and from said gears for meshing the pinion with a particular gear of the series, and a rack and gear mechanism for translating said motor uit on said pivot shaft, said rack being nonrotatably mounted on the shaft relative to the motor unit and in engagement therewith for movement of the motor unit in the respective directions.

10. In a grinding machine, a grinding wheel, a guard for said grinding wheel, a mounting for said guard whereby the guard is movable toward and from the peripheral surface of the grinding wheel, a speed change transmission for driving said grinding wheel, a lever for shifting the gears of said transmission, a linkage between said lever and said guard, and a free connection in said linkage which prevents shifting of the grinding wheel transmission gears to a higher speed depending on the position of the guard and the linkage to the free connection but permits shifting of the gears in the lower speeds below the particular speed as imposed by the guard and grinding wheel relation.

' JOHN A. SMITH.