US 1976130 A
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Description (OCR text may contain errors)
CCL 9, 1934., B, A. KEARNS T AL 1,976,130'
GRINDING II/'IACHINE Filed Dec. l, 1930 2 Shee's-Sheet l @mit 9s E934. s. A, KEARNS ET AL GRINDING MACHINE 2 Sheets-Sheet 2 Filed Dec. l, 1930 Patented Oct. 9, 1934 UNITED STATES PAT T FICE GRINDING MACHINE of Ohio Application December 1, 1930, Serial No. 499,208
This invention relates to improvements in' machine tools and especially to improvements in grinding machines.
One of the principal objects of the present invention is the provision of an improved structure for eiiecting the rotation of tool spindles,
such as a grinding wheel spindle. f f
Another object of the invention is the pro vision of an improved iioating belt drive from a prime mover or initial power source to a shiftable tool spindle which will automatically adjust itself to the position of the spindle and maintain the same in most eiiicient driving position.
Another object of the inventionis the provision of a belt drive mechanism for transmitting motion and power from an initial power source to a shiftable tool carrying spindle or shaft without the use of idler pulleys or the like to maintain proper driving connection between such belt and pulleys.
Another object of the invention is the provision of improved means for mounting the driven member or pulley on a tool carrying shaft or spindlewhich is capable of slight Vreoiprocations without breaking the driving connection between such spindle or shaft and its motion transmitting member while the said member is held in a iixed position.
A further object of this invention is the provision of an improved outboard exible transmission for shiftable rotating shaft carriages that will not eiect a tilting or skewing of the said carriage and shaft carried thereby when said carriage is not gibbed to its support.
A still further object of the invention is the provision of an improved outboard belt drive for grinding wheel spindles so arranged as to take up the belt pull and prevent tilting or misalignment of the carriage.
Other objects and advantages of the present invention should be readily apparent by reference to the following specification considered in conjunction with the accompanying drawings forming a part thereof and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.
1n the drawings:
Figure 1 is a top plan View of a grinding machine embodying the improvements of this in-v vention.
Figure 2 is an end elevation of the machine Vshown `in Figure 1, certain parts thereof being in section as seen from the line 2-2 or Figure 1.
Figure 3 is a vertical sectional view taken on line 3 3 of Figure 2.
Figure 4 is a horizontal sectional view taken on line 4-4 of Figure 2.
Figure 5 is a detail sectional view taken on line 5 5 of Figure 3.
Figure 6 is a sectional View taken on line 6-5 ofv Figure 3.
Figure 7 is a view in section of the driven end of a spindle or shaft showing a slight modification over the showing in Figure 3.
Throughout the several views of the drawings similar reference characters are employed to denote the same or similar parts.
The device of this invention is capable of general use and is not to be construed as applicable solely to a grinding machine which has been chosen for the purpose of illustration and depicted in the drawings. As shown in the drawings the device may comprise a bed 10 having formed at the upper end thereof ways 11 and 12 for the work supporting and traversing table 13. This table 13 supports thereon the headstock 14 and tailstock 15 having extending from them centers 16 between which the work 17 is mounted. The bed 10 is further provided with ways 18 extending transversely of the bed and supporting a tool carriage or slide 19. The tool slide 19 rotatably supports a spindle or shaft 20 and to one end of which has secured for movement therewith a grinding wheel 21. The carriage 19 is adapted to be reciprocated longitudinally of the ways 18 toward and from the work 17 for which purpose adjusting screws 22 is provided. Any suitable means, such as the usual pick feed including ratchet 23, may be employed for rotating the screw 22 and thereby effecting the said shifting movement of the carriage 19.
In the past, belts, or the like, have been employed for rotating the spindle 26 and grinding wheel 21, such belts extended from a line shaft, prime mover, or the like, to a jack shaft from which additional belts extended to the spindle. Idler pulleys or other heavily weighted mechanisms were provided for engaging the belt between the jack shaft and spindle to take up the slack and stretch that necessarily develops in belts or the like during use. By this invention the said idler pulley mechanism and slack taking up structures have been omitted and in their stead a relative noating drive mechanism provided.
For driving the spindle use is made of the prime mover or motor 24 being coupled through coupling 25 to a countershaft 26 journaled in suitable anti-friction bearings 27 carried by a bracket or plate 28, see Figure 4. The bracket or plate 28 provides a relatively long bearing sleeve 29 which extends from the side face 30 of the bed l0 to the interior thereof. A silent chain sprocket 3l is keyed or otherwise secured to the shaft 26 about which is trained silent chain 32 extending in turn about a sprocket 33 fast on the inner end of driven shaft 34. Driven shaft 34 is journaled in anti-friction bearings 35 mounted in sleeve portion 36 of swinging or floating bracket 37. The said bracket 37 has arms 33 and 39 extending therefrom between which is received a tongue 40 carried by the plate bearing sleeve 29. arms 38 and 39 are provided with aligned bores receiving therein a pivot shaft 41 about the axis of which the swinging or floating bracket 37 may be actuated. To permit the said bracket 37 to swing about the axis of the pivot shaft 41 the bracket plate 28 is provided with an enlarged opening 42 to provide suitable clearance therefor.
A multiple belt sheave 43 is secured to the outer end of the driven shaft 34 about which the belts 44 are trained which extend upwardly about a similar sheave 45 connected, as will later appear, to the shaft or spindle 20, as seen in Figure 3, or secured thereto, as seen in Figure 7. A guard and tie plate 46 is mounted about the outer reduced portion 47 of the swinging bracket bearing sleeve 36 and is held thereon against displacement by a collar 48. The plate 45 has extending therefrom flanges 49 and 50 disposed at right angles to one another. The upper portion of the flange 49, as seen in Figure 3, is formed into an attachment tongue 51. The ange 49 and tongue 5l substantially cover the opening 42 formed in the bracket plate 28 while to the flange 50 is secured a hood or guard 52.
An attachment plate 53, similar to the plate 46, surrounds a reduced portion on bearing sleeve 54 secured to the side of sliding carriage 19. The lower portion of the plate 53 is formed into an attachment lug 55 and extends toward the lug 5l. A tie bar 56 having its opposite ends secured to the attachment lug 51 and lug 56 is provided for definitely spacing the attachment plates 53 and 46 from one another which plates adjust the axial distance between spindle or shaft 20 and the driven shaft 34. To provide for adjustment of the said shafts toward and from one another the bar 56 has formed therein elongated perforations 57 and 58 through which extend bolts 59 and 60 respectively, into the attachment lugs 51 and 56. A hood or guard 61, similar to the guard 52, is secured to the plate 53 by means of a flange 62 extending from said plate and encloses the sheave or pulley 45 on the shaft or spindle 20.
From the foregoing it will be noted that the shaft or spindle 26 and driven shaft 34 are spaced from one another a denite distance corresponding to a size of the belts, or the like, 44 so that the most eflicient driving connection between said belts and the sheaves is provided. As the tool carrying slide or carriage is reciprooated along the Ways 18 the straight line distance between the centers of the spindle 20 and shaft 34 tends to decrease which, however, is prevented by the tie bar 56 which merely depresses The tongue 40 andor oscillates the driven shaft by swinging the bracket 37 about the axis of pivot shaft 41 in a counter clockwise direction until the point directly above the shaft 34 is passed whereupon an upward swing of the bracket 37 takes place.
Referring to Figure 2 it will be noted that hood or guard 52 is provided on opposite sides with belt openings63 and that hood or guard 61 is similarly provided with openings 64 whereby the belts pass beyond the said hoods or guards. Secured to the guard 52 surrounding the openings 63 are telescoping members 65 receiving one end of tubular guards 66 which surround the belt intermediate the hoods 52 and 6l. Similar telescopic guard members 67 are secured to the hood or guard 61 and receive the other end of the tubular guards 66. From this it will be seen that as the distance between the axial centers of the spindle 2O and shaft 34 is changed or varied the guards will accommodate themselves by telescoping within one another thereby keeping the belts 47 completely enclosed at all times. The spindle sheave 45, shown in Figure 3, is mounted on anti-friction bearings 68 which surround the sleeve 54 secured to and extending from the tool slide i9. The said sleeve 54 is provided adjacent the attachment plate 53 with a shoulder 69 and on its free end with threads for a lock nut 70. A spacer 7l is provided intermediate the anti-friction bearings 68. The bearings are locked on the sleeve 54 by clamping same between the shoulder 69 and nut 70 having the spacer 71 between for properly tensioning the bearing members of the anti- :iction bearings 68. Splined to the cuter end 72 of the spindle or shaft 26 is a spider 73 secured against movement relative to the spindle by a nut 74 clamping said spider between itself and a shoulder 75 on the spindle. The spider 3 is provided with a series of radial notches 76 receiving driving rollers 77 therein. Each roller is carried by a pin 78 extending from the sheave 45.
From the foregoing it will be seen that rotation of the sheave 45 will, through the engagement of the rollers 77 within the slots 76, rotate the spider 73, which being splined or otherwise secured on the spindle 20 will rotate the said spindle in the same direction and at the same speed as the sheave 45 is being rotated. This construction permits a reciprocation of the spindle 20 axially of itself without shifting the sheave 45 and without breaking the driving connection between the said spindle and the sheave. Any suitable or desirable means may be provided for effecting the reciprocation of the spindle 20. One form of spindle reciprocator is disclosed in Figure 3, which includes a barrel cam 79 secured to the spindle 20 having the cam slot 80 formed therein. A shoe 81 carried by the detractable pin 82 is received in the cam groove 80. The pin 82 being supported against movement axially of the spindle 20 by the tool carriage 19. It will be seen that a rotation of the spindle 20 with the parts as shown in Figure 3, will elfect an axial shifting or reciproeation of the spindle 20 toward the left, as seen therein, during onehalf of a revolution of the spindle and a reverse shifting during the second half of the revolution. The rollers 77 being mounted for rotation about the axis of pin 78, which extend at right angles to the shifting movement of the spindle 20, offer no resistance to such movement and the spider 73 is of a width to prevent the said rollers 77 from leaving the grooves 76 thereby at all times maintaining a driving connection between the spindle and driving sheave 45.
It is to be understood that the invention need not be applied only to a reciprocating type of spindle but may be secured to a spindle lixed in its bearings against relative axial shifting. As shown in Figure 7, this type of construction is illustrated in which the bearing housing 83 is provided with a turned nose 84 on which is journaled the attachment plate 53. The spindle 20 extends beyond the bearing portion 83 and has formed thereon a tapered portion 85 on which is mounted the spindle sheave 45. Lock nuts 86 secure the said sheave on the tapered portion 85. Thrust bearings 87 surround the spindle intermediate the journal or collar portion 84 and the tapered portion S5 for taking up side thrust on the said spindle.
The operation of the improved spindle drive construction should be readily understood from the foregoing description and it will be noted that no idlers or other belt tensioning mechanisms have been provided to take up slack or the like in the belt as the center distance between the spindle and driven shaft varies due to a shifting of the spindle carriage or due to stretch of said belts. It will further be noted that an improved mounting for a driving pulley, member or sheave on a driven tool spindle or the like has been provided which tool spindle may be axially reciprocated through a limited stroke without destroying or interfering with the driving coupling thereof. It will further be noted that the transmission members, such as belts, chains or the like, are at all times completely enclosed within suitable housings or guards reducing danger of moving exposed parts to an absolute minimum.
The improved belt drive mechanism here disclosed is particularly advantageous for use for driving or rotating spindles or other shafts carried by shiftable carriages or supports, such as the wheel head of a. grinding machine which mounted on a suitable table or support without the use of gibs or other holding down structures. In the past, outboard transmissions tended to tilt the said carriage through the enormous belt pull on the end of the spindle disposing the said carriage and spindle in an angular relation relative to the bed. In the mechanism here illustrated and described the tie bar 5S definitely spaces the pulleys on the spindie and the driven shaft from one another and takes the belt pull relieving the carriage and spindle from this tension.
l. In a machine tool organization the combination of a bed, a carriage carried thereby and shiftable relative thereto in a horizontal piane, a spindle rotatably supported by the cara floating driven shaft carried by the bed, adjustable means for dennitely spacing the axes of the spindle and driven shaft from one another comprisiirT a tie bar having its opposite ends secured to attachment members carried by the spindle and floating shaft, pulleys on the ends of the spindle and driven shaft, transmission belts extending between the pulleys, a separate guard enclosing each of the pulleys, and additional guards extending between the pulley guards and telesccping therewith for enclosing the transmission belts whereby the pulleys and belts are adequately guarded regardless of the distance between the axes of the spindle and drive shaft.
2. In a machine tool organization the combination of a bed, a carriage carried thereby and shiftable relative thereto in a horizontal plane, a spindle rotatably supported by the carriage, a floating driven shaft carried by the bed, adjustable means for definitely spacing the axes of the spindle and driven shaft from one another comprising a tie bar having its opposite ends secured to attachment members carried by the spindle and iioating shaft, pulleys on the ends of the spindle and driven shaft, transmission belts extending between the pulleys, a separate guard enclosing each of the pulleys, additional guards extending between the pulley guards and enclosing the transmission belts, and extensible connections between the belt guards and pulley guards whereby relative adjustment between the axes of the spindle and driven shaft may be had without exposing either the pulleys or belts.
3. In a grinding machine the combination of a spindle, bearings rotatably supporting the spindle, means for effecting a limited reciprocation of the spindle through its bearings, a sleeve secured to the bearings and encircling the end of the spindle, a transmission member journaled on the sleeve, and means carried by the spindle for reciprocating movement therewith coupled with the transmission member whereby motion is imparted to the spindle.
4. In a grinding machine the combination of a spindle, bearings rotatably supporting the spindle, means effecting a slight reciprocation of the spindle through its bearings, a sleeve secured to the bearings and encircling the end of the spindle, a pulley journaled on the sleeve, a spider secured to the spindle and positioned interiorly of the pulley, a sliding driving connection between the pulley and spider whereby the spindle may be reciprocated without breaking the driving connection between the pulley and the spider.
5. In a belt transmission for grinding wheel spindles and the like the combination of a carriage, a spindle rotatably mounted in the carriage and extending beyond the lines thereof, a pulley support secured to the carriage and having journaled therein the extending portion of the spindle, a power transmission pulley journaled on the pulley support, means for rotating the pulley on its support, means secured to the spindle for connecting same with Ythe pulley whereby rotation of the pulley effects rotation of the spindle, a sliding connection between the spindle and pulley connecting means, and means for reciprocating the spindle axially of itself relative to the carriage.
6. In a device of the class described the combination of a support, a spindle rotatably mounted therein and having one end projecting therebeyond, a sleeve secured to the support and encircling the projecting end of the spindle, a power transmission member rotatably mounted on the sleeve, roller clutch members projecting inwardly from the power transmission member,
BERNARD A. KEARNS. FREDERICK S. HAAS.