US2017465A - Tool grinding machine - Google Patents

Description

zmmss Get. 15, 1935. P. T. LENNON v TOOL GRINDING MACHINE Filed Jan. 22, 1951 3 Sheets-Sheet l Oct. 15, 1935." P. T. LENNON r001. GRINDING MACHINE Filed Jan. 22; 1931 3 sheets sheet 2 /047//C/ flan/Noni Wmvma Get 1935. P. T. LENNON TOOL GRINDING MACHINE Filed Jan. 22, 1951 s Sheets-Sheet 5 Patented Oct. 15, 1935 UNITED STATES ENT OFFICE 9 Claims.

This invention relates to metal working machines, particularly machines for grinding reamer blades and the like.

It is among the objects of this invention to provide a machine which will grind radial relief on reamers or similar tools which have blades, flutes or teeth irregularly spaced. Furthermore, it is an object to provide a machine which will grind reamers of various makes, designs or constructions. It is a further object of this invention to provide electric magnetic control to synchronize the action of the grinding wheel and reamer blade. Another object is to provide a reamer grinder wherein the grinding wheel will be controlled by the blade being ground.

Other objects relating to details of construction and economies of manufacture will appear hereinafter.

In the accompanying drawings which in connection with the following description, disclose a preferred embodiment of the invention.

Figure l is a front elevation of a machine con structed in accordance with this invention, parts being broken away to more clearly show the construction.

Figure 2 is a view taken along the lines Z2 in Figure 1 looking in the direction of the arrows.

Figure 3 is a fragmentary view of the grinding wheel and infeed control, partly in section and partly in elevation.

Figure 4 is a fragmentary end elevation of the grinding wheel and infeed control.

Referring to the drawings, the machine is mounted upon a base frame I0, and consists generally of means for mounting, rotatin and feeding the grinding wheel, and means for holding and rotating the work. As seen more clearly in Figure 2, the grinding wheel is supported by a sliding carriage ll adjustably mounted on the frame ID. A bell crank lever I2 is pivoted to the sliding carriage H, and carries at its upper end a clamp l3. A cylindrical post I4 is secured in the clamp l3 and terminates in a bracket l5 having a pair of spaced offset bearings IS in which the spindle I 6 of the grinding wheel I! is journalled. A pulley l8 secured to the spindle I6 between the bearings 15 is arranged to receive a belt IQ for rotating the grinding wheel.

The belt l9 passes through guide pulleys 20 mounted on the frame l0 and is driven by a pulley 2| keyed to the shaft 22 of an electric motor 23 or other source of power. The shaft 22 is extended and carries a worm gear 24 meshing with a worm wheel 25 keyed to a vertical 55 shaft 26. The shaft 26' drives a second vertical shaft 21 through a belt 28 passing around pulleys 29 and 39. A bevel gear 3| on the lower end of the shaft 21 meshes with a bevel gear 32 on a horizontal cam shaft 33. The shaft 33 is journalled in brackets 34 and 35 carried by a 5. beam 36 secured to the frame 10.

The bracket H is formed with a dovetailed base 31 fitting within a channel 38 formed in a laterally extending frame member 39. A screw shaft journalled in the frame l0 extends into 10 screw threaded engagement with the base 31 of the carriage H and is provided with a handwheel 4| by which the position of the carriage H may be adjusted.

The work is carried by a table 42 mounted for 15 longitudinal sliding movement 'on the frame I0. The table 42 is provided with V-shaped guides or legs 43 fitting within complemental grooves 44 formed in the base to guide the table in its sliding movements. A footstock 45 is adjustably 20 mounted on the table 42 in the usual manner, and a headstock 46 is fixed thereto. A spindle 4? is journalled in the headstock 43 and carries the live center 48 which co-operates in the usual manner with the center 49 carried by the foot- 25 stock 45 to hold the work, illustrated as a reamer 50. Rotation of the spindle 41 is imparted to the reamer 50 by an arm 5| adjustably clamped to the reamer and engaging a notched disc 52 on the spindle. 30

The spindle 41 is driven by a gear 53 meshing with a gear 54 mounted on a countershaft 55 journalled in suitable bearings in the table 42.

The shaft 55 is formed with keyways 56 to slidably receive a hub 51 of a bevel gear 64 having 35 splines engagingin the keyways to hold the hub and shaft against relative rotation.

The upper end of the vertical shaft 27 has affixed thereto a sleeve 58 terminating in a bevel gear 59. The lower portion of the sleeve 58 is 40 journalled in a bracket 60 fixed to the frame. II] in any suitable manner, to provide a bearing and support for the shaft 21. Above the bracket 60 the sleeve 58 bears in a yoke 6| having a pair of arms terminating in bearings 62 and 63. 45 The bearing 62 surrounds the hub 51 to position the same with respect to, thevertical shaft 21. The bearing 33 surrounds the shaft 55 to prevent rotation of the yoke 61. The sleeve 51 on the shaft 55 terminates'in the bevel gear 64 held in mesh with the gear 59 by means of the yoke 6|. It will be seen that rotation of the shaft 21 is imparted to the shaft 55 by the bevel gears 59 and 64, while longitudinal sliding mo- 55 tion of the shaft 55 is permitted by the keyways 56 and co-operating splines on the hub 57.

It will be evident from the foregoing description that the motor 23 drives the grinding wheel I I at a relatively high speed by means of the belt I9, and simultaneously rotates the cam shaft 33 and the work at a relatively low speed. As illustrated the grinding wheel is relatively narrow with respect to the length of the work so that but a portion of a blade is ground at a time. In order to present different portions of the work to the grinding wheel, means are provided for sliding the table 42 longitudinally. If desired, automatic means may be used for this purpose, but in order to simplifythe machine I prefer to provide the table witha rack 65 engageable by a gear 66 carried on a shaft 61 jour nalled in the frame I 0. A hand wheel 68 is aflixed to the shaft 61 and may be rotated to move the table in either direction.

A cam disc 69 for producing the desired infeed is freely mounted on the shaft 33. The lower end of the lever I2 carries a cam roller I0 which is held pressed against the cam disc by a spring II. The periphery of the disc 69 is substantially circular and concentric with the shaft 33, the eccentric or cam surface being formed by a section I2 pivoted to the disc at I3 and held in adjusted position by any suitable means such as a bolt 14. The disc 69 is provided with an extended sleeve I5 bearing on the shaft 33 and held against excessive endwise'movement by a thrust bearing, such as a nut I6 on the end of the shaft 33. A spring TI connected to the sleeve I5 and to a stud I8 carried by'the beam 36 normally maintains the sleeve and disc against the thrust hearing I6.

A magnetic clutch I9 is fixed to the'shaft33 and preferably comprises an annular core and windings 8 I. The face of the core 80 is positioned a short distance from the disc 69, the latter being composed of ferrous material so that it may be coupled to the clutch I9 when the windings are energized by a suitable electric current. Collector rings 82 are carried by the opposite face of the clutch I9 and are arranged to be engaged by brushes 83 mounted on the bracket 35. When the clutch I9 is energized, the disc 69 is coupled therewith and rotates with the shaft 33. When the clutch is released, the spring 1'! draws the disc out of engagement with the clutch, freeing it from the shaft 33. A spring 84 connected to the disc 69 and to a bracket 85 carried by the beam 36 returns the disc to the position shown in Eigure 2 when the clutch isreleased. If desired, a stop may be provided to limit the return rotation of the disc under the influence of the spring 84.

lilnergization of the clutch I9 is effected by a switch means controlled by the blade being ground. As shown in Figures 3 and 4, the upper portion of the grinding wheel I I is enclosed by a guard 86 carried by the bracket I5. of lugs 81 and 88 are mounted on the guard 86 on opposite sides of the grinding wheel. A pin 89 is pivoted in the lug 81 and carries an arm 90 which is provided with a second pin 9I parallel with and slightly above the pin 89.- A roller 92 is rotatably mounted on the pin 9| and'is adapted to engagethe work immediately adjacent the grinding wheel. Similarly, an arm 93 is pivoted to the lug 88 and carries a roller 94 on the opposite side of the grinding wheel. The lower ends of the ' arms 90 and 93 are firmly connected together by means of a bar 95. 7

' between the centers 48 and 49.

' the contact 91.

A pair The arm 90 is extended beyond the pins 89 and; 9I and carries at its upper end a contact mem-- ber 96. A co-operating contact 91 is carried by an arm 98 pivoted to the lug 81 and held against a stop 99 by a flat spring I00. Springs IOI attached to the bracket I5 and to the arms 90 and 93 normally hold the contact 96 spaced from the contact 91, the arm 90 abutting a stop I02. Conductors I93 connect the collector rings 82 with a suitable source of electric current through the contacts 96 and 91.

In operation, a reamer or the like 50 is secured The grinding wheel I! is then brought into proper position to grind the high edges of the blades by sliding the post I4 through the clamp I3, final adjustment being effected by rotating the hand wheel 4| to slide the carriage II toward or away from the work. If the blades or flutes of the work are straight, as illustrated, the grinding wheel is positioned inavertical plane. However, when it is desired to grind a tool with spiral blades, the post I4 is rotated in the clamp I3 until the grinding wheel lies'in a plane perpendicular to the length of the blades.

The motor 23 drives the grinding wheel through the belt I9 in the direction of the arrows at a relatively high speed, and simultaneously drives the work and the camshaft 33 in the directions indicated by the arrows at a relatively low speed. As a blade of the reamer approaches the grinding wheel, it first contacts the rollers 92 and94 and moves the arms 90 and 93 about their pivotal axis to cause the contact 96 to approach The relation of the rollers 92 and 94 to the pivotal axis of the arms is so adjusted that the contacts 96 and 91 close the electrical circuit and energize the magnetic clutch I9 before the edge of the reamer blade engages the grinding wheel. The clutch thereupon grips the cam disc 69 and rotates the same with the shaft 33. As thereamer continues its rotating, the rotation of the cam disc 69 causes the lower end of the lever I2 to move outwardly against the tension of the spring 1|, thereby moving the grinding wheel inwardly towards the work. The

this amount. However, the amount of infeed can a be readily adjusted by swinging the section I2 about its pivot I3. 7

During the continued rotation of the reamer and infeed of the grinding wheel after a blade edge first contacts the'wheel, the engagement of the blade with the rollers 92 and 94 holds the contacts 96 and 91 in engagement and presses the arms 90 and 98 rearwardly against the tension of the spring I00. As the blade rotates past the grinding wheel, the spring IOI draws the contact 96 from the contact 91' and breaks the clutch circuit. At'this time the cam disc 69 has rotated about 15 degrees from its initial position against the tension of the spring .84. As the current energizing the clutch is interrupted, the spring 11 draws the disc 69 directly away from the clutch and against the stop I6, whereupon the. spring 84 returns the cam disc to its initial position.

It will be evident that as the work rotates the grinding wheel is fed inwardly to relieve each blade the required amount. When the grinding wheel is narrow with respect to the length of the work, as in the embodiment disclosed, successive portions of the blades are brought into engagetil ment with the wheel by turning the handwheel 68 to slide the table 42 along the base.

Although the foregoing description is necessarily of a detailed character in order that the invention may be fully disclosed, it is to be understood that the invention may be embodied in other mechanisms and that various modifications and re-arrangements of parts may be resorted to without departing from the scope of the invention as defined by the following claims.

I claim:

1. In a machine of the class described, the combination of a grinding wheel, work supporting means, a drive shaft having connections for rotating said grinding wheel and the work at a relative- 1y uniform speed, means for producing a relative infeed between said grinding wheel and the work including an eccentric member, and magnetic clutch means controlled by the work for coupling said eccentric member with said drive shaft.

2. In a grinding machine, the combination of a grinding wheel, a rotatable work-holder, means for driving said wheel and work-holder, and means for producing a relative infeed movement between the wheel and holder; said means including a rotatable cam member, magnetic means operatively associated with said cam member to cause rotation of the latter, a feeler member mounted for contact with the work being ground, an electric circuit for said magnetic means including spaced contacts operatively connected to said feeler member and arranged to be moved into contact and close the circuit to said magnetic means and cause rotation of the cam member, and infeed-motion-transmission means operatively associated with said cam member.

3. In a grinding machine, the combination of a grinding wheel, a rotatable work-holder, means for driving said wheel and work-holder, and means for producing a relative infeed movement between the wheel and holder; said means in cluding a rotatable cam meber, magnetic means operatively associated with said cam member to cause rotation of the latter, a feeler member mounted for contact with the work being ground, an electric circuit for said magnetic means including spaced contact operatively connected to said feeler member and arranged to be moved into contact and close the circuit to said magnetic means and cause rotation of the cam member, infeed-motion-transmission means operatively associated with said cam member, and means for radially adjusting the cam member to thereby adjust the degree of infeed movement.

4. In a tool grinding machine, the combination of a rotatable and bodily movable grinding wheel, a rotatable work-holder, means for driving said wheel and work-holder at a relatively uniform speed, and means for producing a relative infeed movement between the wheel and holder; said means including a magnetic means, a rotatable cam member operatively associated with said magnetic means to be rotated through energization of the latter, a feeler member mounted adjacent the work-holder for contact with the tool being ground, an electric circuit for said magnetic means including spaced contacts operatively connected to said feeler member and arranged to be moved into contact and close the circuit to said magnetic means and cause rotation of the cam member, and means for transmitting an infeed movement from the cam member to the grinding wheel to move the latter toward the work.

5. In a grinding machine, the combination of a rotatable and bodily movable grinding wheel, 5

a rotatable work-holder, means for driving the said wheel and work-holder at a relatively uniform speed, and means for producing a relative infeed movement between the wheel and holder; said means including a magnetic clutch and a rotatable cam member operatively associated with said clutch to be rotated thereby, a feeler member mounted adjacent the work-holder for contact with the work being ground, an electric circuit for said clutch including contacts operatively 5 connected to said feeler member and arranged to be moved into contact by the latter and close the clutch circuit and cause the clutch to engage and rotate the cam member, and means for transmitting an infeed movement from the cam member to the grinding wheel to move the latter toward the work.

6. In a tool grinding machine, the combination of a rotatable and bodily movable grinding wheel, a rotatable work-holder, means for driving said 5 wheel and work-holder at. a relatively uniform speed, and means for producing a relative infeed movement between the wheel and holder; said means including a magnetic clutch which is operatively connected to said driving means and a rotatable cam disc operatively associated with said clutch to be rotated thereby, an adjustable cam member on said disc, a feeler member mounted adjacent the work-holder for contact with the tool being ground, an electric circuit for said 5 clutch including spaced contacts operatively connected to said feeler member and arranged to be moved into contact by the latter and close the clutch circuit and cause the clutch to engage and rotate the cam disc, and means for transmitting an infeed movement from the cam member to the grinding wheel to move the latter towards the work.

'7. In a grinding machine, the combination of a grinding wheel, work supports, means for driving the work arranged to drive a camshaft at a speed having a fixed ratio to the speed of the Work, a cam for producing a relative infeed between said grinding wheel and said'work supports, and a clutch for intermittently coupling said cam to said camshaft for rotation therewith.

8. In a grinding machine, the combination of a grinding wheel, work supports, means for driving the work arranged to drive a camshaft at a speed having a fixed ratio to the speed of the work, a cam for producing a relative infeed be tween said grinding wheel and said work supports, and a magnetic clutch controlled by the work.

9. In a grinding machine, the combination of a grinding wheel, work supports, means for driving the work arranged to drive a camshaft at a speed having a substantially fixed ratio to the speed of the work, a cam for producing a relative infeed between said grinding wheel and said work supports, and an electric magnetic clutch controlled by the work for coupling said cam with said camshaft for rotation therewith.

PATRICK T. LENNON.

Images