US2720734A - Automatic infeed and ejecting devices for centerless grinders - Google Patents

Description

Oct. 18, 1955 J. E. HECKETHORN 5' AL 2,720,734

AUTOMATIC INFEED AND EJECTING DEVICES FOR CENTERLESS GRINDERS Flled Aug 17 1953 4 Sheets-Sheet 1 Oct. 18, 1 5 J. E. HECKETHORN El AL 2,720,734

AUTOMATIC INFEED AND EJECTING nsvrcss FOR CENTERLESS GRINDERS Filed Aug. 17, 1953 4 Sheets-Sheet 2 Oct. 18, 1955 Filed Aug. 17, 1953 .1. E. HECKETHORN El AL 2,720,734 AUTOMATIC INFEED AND EJECTING DEVICES FOR CENTERLESS GRINDERS 4 Sheets-Sheet 3 JNVENTORS Oct. 18, 1955 J. E. HECKETHORN El AL 2,720,734

AUTOMATIC INFEED AND EJECTING DEVICES FOR CENTERLESS GRINDERS 4 Sheets-Sheet 4 Filed Aug. 17, 1953 INVENTORS a/Y/YAI' drxr United States Patent AUTOMATIC INFEED AND EJECTIN G DEVICES FOR CENTERLESS GRINDERS John E. Heckethorn and Clarence Richard Dickson, Littleton, C0lo., assignors to Heckethorn Manufacturing & Supply Co., Littleton, Colo.

Application August 17, 1953, Serial No. 374,522 13 Claims. (Cl. 51-215) which Will positively accurately and continuously feed the work to the machine, subject it to the proper precision grinding; and eject it upon completion of the grinding.

Another object of the invention is to so construct the device that it will be practically fool-proof, so that should the infeed become clogged for any reason, the feeding mechanism will cease to function without damage to the mechanism, and to provide a device which can be accurately regulated to remove only the required amount of material during the grinding operation.

Another object of the invention is to so construct the device that it will operate synchronously with the advance and withdrawal of the feed wheel of a conventional centerless grinding machine.

A still further object is to provide a device of this character which will be economical to manufacture, rugged in structure and positive in operation.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and eficiency. These will become more apparent from the following description.

In the following detailed description of the invention, reference is had to the accompanying drawings which form a part hereof. Like numerals refer to like parts in all views of the drawings and throughout the description.

in the drawings:

Fig. 1 is a fragmentary, perspective view of the upper portion of a conventional centerless grinding machine, illustrating the invention applied thereto;

' Fig 2 is a detail, sectional view, taken on the line 2-2, Fig. 4, illustrating a face cam employed in the improved iufeed and ejecting device;

Fig. 3 is an enlarged end view of the improved infced and ejecting device applied to a conventional centerless grinding machine and looking in the direction of the arrow 3 in Fig. 4;

Fig. '4 is a plan view of the inr'eed and ejecting device removed from the centerless grinding machine;

Fig. 5 is an enlarged, detail cross-section, taken on the lines 55, Fig. 4, and Fig. 6;

Fig. 6 is a similarly enlarged, fragmentary, longitudinal section, taken on the line 66, Fig. 5; and

Fig. 7 is a detail, sectional view, taken on the line 7-7, Big. 3.

Parts of a conventional centerless grinder are designated on the drawing by numeral as follows: bed 10, grinding wheel 11, feed wheel 12, feed wheel motor housing 13, feed wheel carriage 14, feed wheel carriage feed screw 15,

' of the crank member 36.

2,720,734 Patented Oct. 18, 1955 feed wheel feed sleeve 16, grinding wheel housing 17, work rest 18, and work rest holder 19.

In the usual centerless grinder, the feed screw 15 is threaded through the feed sleeve 16 and the latter is mounted in the feed wheel carriage 14 between suitable end thrust bearings. Thus, rotation of the feed screw 15 in the sleeve 16 moves the carriage 14 and rotation of the sleeve on the stationary feed screw also acts to move the carriage.

In such a machine the work being ground rests upon the work rest 18 between the grinding wheel 11 and the feed wheel 12. The feed screw 15 is rotated by means of a hand wheel to bring the feed wheel carriage 14 adjacent the work. The feed sleeve 16 is then manually rotated on the feed screw to move the carriage 14 forwardly for a pre-set distance sufiicient to bring the work to the required finish diameter after which the feed sleeve is returned to its original position. Therefore the amountof rotation of the feed sleeve 16 determines the amount of grinding which will be done and the sleeve must be reciprocated forward and back the pre-set distance for each article to be ground. The wear of the grinding wheel is adjusted during operation by rotation of the hand wheel.

This invention is designed to automatically place the work between the wheels 11 and 12; then rotate the feed sleeve 16 at the proper speed and for the proper distance to remove the required material from the work; then withdraw the feed wheel 12 by return motion of the feed sleeve 16; and thence eject the finished piece of work from between the wheels 11 and 12. With the exception of the grinding Wheel 11, only the parts added to the standard machine are shown shaded in the drawings. The unshaded parts will be found in all standard machines.

The improved device employs a base plate 23 which is mounted on and attached to the motor housing 13 in any desired manner, such as by means of cap screws 24 as shown in Fig. 4. The base plate carries an operating motor 25 which, through the medium of a V-belt 26 and a speed reducer 27, rotates a cam shaft 28. The speed reducer 27 may be any of the standard commercial varieties, and will be herein designated in its entirety by the numeral 27. The shaft 28 projects from both sides of the speed reducer 27 and on the front side terminates in a relatively large cam plate 29, provided with a face cam track 30. At its other extremity the shaft 28 terminates in a second cam plate 31.

A rocker arm 32 is journalled in suitable bearings 33 on the plate 23, and projects through a suitable opening in the latter so as to extend both above and below the plate. The upper extremity of the rocker arm terminates in a cam follower roller 34 which rides on and follows the contour of the cam track 38. The lower extremity of the rocker arm 32 terminates in a crank pin 94 upon which one extremity of a connecting rod 35 is mounted. The other extremity of the connecting rod 35 is slidably mounted in a spring sleeve 96 from which a pivot stud 99 projects into a crank member 36 clamped on the feed sleeve 16. Outward movement of the connecting rod 35 is limited by a stop pin 97 therein which rides in a limiting channel in the sleeve 96, see Fig. 7. A cushion spring 37 is positioned in the spring sleeve 96 between a closed extremity of the latter and the extremity of the connecting rod 35 so that the rocker arm 32 may have a greater arc of movement than the crank member 36. The are of movement of the latter is regulated by means of a limit screw 38 projecting from an arm 39 formed on the crank member 36. This limit screw is positioned to contact a stop 22 supported from a bracket arm plate attached to the end of the feed carriage 14 by means of suitable cap screws 98, and acts to preset the forward movement Itcan be readily seen that if the cam plate 29 rotatesin' the direction of the arrow in Fig. 3, the contour of the cam track will cause the upper extremity of the arm 32 to swing to the right in Fig. 3. It will be held in this position for approximately one-half a revolution,

after which the low portion of the cam track will allow the upper extremity of the arm 32 to swing to the left for approximately one-half. a revolution. The movement of the upper extremity to the right causes the lower extremity of the rocker arm to swing the crank member 36 so as to actuate the feed sleeve to move the feed wheel 12 toward the work. After the grinding has been completed, the movement of the upper extremity of the rockerarm to the left will withdraw the feed wheel from the work to allow the work to be removed and replaced;

The amount of advance of the feed wheel is regulated-by the limit screw 38 which contacts the stop 22 and stops the movement of the crank member 36. The arm 32 continues its movement against the action of the cushioning spring 37.

, As thus far described, the improved infeed and ejecting device is similar to that illustrated and described in the I said prior Patent No. 2,379,661. This invention relates attached to the machine for delivery of the work pieces.

thereto. The chutes are provided with guide keels 45, as shown in Fig. 3, extending downwardly from the track bars 40. 'To' attach the chute. the guide keels 45 are rested in grooved rollers 46 supported in a bracket arm 47 mounted on the bracket arm plate 95., The forward extremities of the track bars 40 are engaged with rigid track bars 43 fixed in a feed box 44. They are then detachably attached to the rigid bars by means of a removable threaded attachment pin 100, as shown in Fig. 3.

The feed box contains a feed shaft 48 extending trans- V versally below the rigid track bars 43. Two spacedapart feed discs 49 are concentrically and fixedly mounted on a disc sleeve 92 which rides on a tubular bearing 91 surrounding the feed shaft 48. Each of these discs is provided with a work-receiving notch 50, the notches in the two discs being in alignment with each other. The discs and their connecting disc sleeve 92 are reciprocated through an arc of substantially 90. At each reciprocation, the lowermost work piece in the feed chute will roll into the notches 50, as shown in Fig. 6, and be carried forward with the notches as they travel forwardly. The

.next successive work piece will contact and be held back by the peripheries of the discs 49 so as to stop the entire feedrow of pieces until the notches again return to receiving position. r

The discs are reciprocated through the medium of a resilient extensible connecting rod. The rod consists of a forward L-shaped extremity 51 which is eccentrically.

attached to oneof the notched discs 49 by means of a crank s'crew52. A plunger rod53 extends from the extremity 51 .into a spring tube 54 terminating in an enlarged head '55. Both extremities of the spring tube 54 are closed and a compression spring 56 is contained therein about the plunger rod 53. A connecting bar 57 may be attached at any desired point along the spring tube 54 by means of a clamping sleeve 58'actuated from. v

a clamping screw 59.

Thus, it can be seen that the total length of the connecting rod can be preset or varied by varying the posi-' tion of the clamping sleeve 58 along the spring tube 54. It can also be seen that should rotation of the discs 49 be'obstructed in any way, the entire connecting rod can cation of the transfer shaft 75. The latter shaft extends rearwardly alongside the feed wheel carriage 14 and a '4- I lengthen by compressing the spring 56 without damage to the machine or the Work pieces therein. The top of the feed box 44 is provided with inturned flanges 93 which prevent the work pieces from leaving the notches 50 until they have reached the full forward discharge position.

The rear extremity of the connecting bar 57 is mounted on a hinge bolt 60.carried in the lower extremity of a feed lever 61 which is pivotally mounted on a mounting block 81 fixed on the base plate 23 upon a suitable pivot member 62. The lever61 extends upwardly above the pivot member 62 and terminates in a cam-follower roller 63 which rides against the forward face of the second cam plate 31. The latter cam plate is provided with a projecting cam boss 64 so positioned that once during each revolution of the cam plate the boss will pass beneath the'roller 63 and force the upper extremity; 'of the feed lever 61 forwardly, causing the lower extremity to swing rearwardly. This draws upon the connecting rod assembly 51, 54, and 57, causing the upper notched portions of the feed discs 49 to rotate forwardly to deliver a work piece 21. The entire feed assembly is returned to its initial position after the passage of the V cam boss by means of a tension spring 65 which is tensioned between the lower extremityof the feed lever 61 and a spring bracket 66 secured to the side of the base plate 23.

The work piece is received between two parallel,

spaced-apart'side plates 68 which are secured to the sides of an injection carriage 67, by means of suitable screws 7 arranged to swing in a vertical plane parallel to the axes ofthe grinding wheel 11' and feed wheel 12 in alignment with the work rest 18. The upper extremities of the links 72 and 73 are mounted on hinge pins 102 in the carriage 67. The lower extremity of the inner link 72 (toward the wheels 11 and12) is mounted'on a rotatable hinge shaft 74, and the outer link 73is fixedly mounted on an oscillating transfer shaft 75. The shafts 74 and 75 are mounted infsuitable anti-friction bearings The bearingplate 77 is secured to the feed wheel carriage 14 inany suitable man! I ner such as by means of cap screws 78. The point of. attachment is intermediate the work rest 18 and the.

76 in a bearing plate 77.

feed box so that the injection carriage'67 will swing downwardly as it approaches either the rest 18 or the box 44. a

The injection carriage is reciprocated back and forth a 7 between the work rest 18 and the feed box 44 by reciprothrough a supporting bearing' 79 supported fromthe bracket arm 47. An actuating lever 80 is fixedlymount-f ed on the rear extremity of the transfer shaft. This .lever is connected by means of a connecting link .82 V with the lower extremity of an injection lever 83. 'The. 7

injection lever is formed on an injection shaft 84 journalled on the base plate 23 between the mounting block 81 and a pillow block 85'. A'cam follower lever86 is also secured on the injection shaft 84 and extends upwardly therefrom rearwardly of the second cam plate 31 terminating in a cam follower roller 87. Therear'face of the second cam plate 31 is provided with a cam track 88, see Fig. 2, which receives, and is followed by the follower roller 87.

' It can be'seen that when the second cam plate 31 is rotated, the eccentricities of the cam track 88 will be communicated to the follower lever 86 and from thence through the injection lever 83, the link 82, the actuating lever 80, the transfer shaft 75, and the parallel link 73 to the injection carriage 67. The cam follower lever 86 is relatively shorter than the injection lever 83 and the actuating lever 80 is relatively shorter than the link 73 so that the eccentricities of the cam track 88 will be multiplied at the injection carriage 67.

When the cam follower roller 87 reaches the point of greatest radius of the cam track 88, the injection carriage 67 will be positioned adjacent the work rest 18 with the side plates 68 positioned at each side of the rest and with the Work piece resting on the rest 18 in grinding position. When the roller 87 reaches the point of least radius of the cam track 88, the injection carriage 67 will be positioned adjacent the feed box 44 with the side plates 68 in position to receive a work piece from the feed discs 49.

A finished work chute 20 is positioned forwardly of the feed box 44 at the point of greatest outward movement of the injection carriage 67' to receive the finished work pieces as the feed discs 49 force the next successive work piece onto the injection carriage.

Operation Let us follow the progress of a single work piece 21 through the machine. The piece rolls down the track bars 40 of the feed chute until stopped by the feed discs 49. The latter rotate rearwardly until the notches 50 receive the piece. They then rotate forwardly to carry the piece over and deposit it between the side plates 68 of the injection carriage 67. The latter now swings upwardly, inwardly and downwardly to deposit the work piece on the work rest 18 of the grinder.

The cam follower roller 34 now starts to climb the cam track 30 to swing the rocker arm 32 so as to cause it to impart rotation to the carriage feed sleeve 16 so as to cause the feed wheel 12 to approach the work piece and hold it against the grinding wheel 11. The grinding phase is maintained for a preset time interval depending upon the speed of the cam plate 29 and the contour of the cam track 30 therein.

At the termination of the grinding interval, the upper extremity of the rocker arm 32 swings toward the axis of the cam plate 29 causing the feed sleeve 16 to be reversed so as to separate the feed wheel 12 from the grinding wheel 11. The cam track 88 in the rotating second cam plate 31 now causes the upper extremity of the cam follower lever 86 to swing away from the cam axis to rotate the transfer shaft 75 and cause the side plates of the carriage 67 to lift the finished work piece from the work rest 18 and carry it upwardly, outwardly and downwardly to its original position opposite the feed box 44.

The cam boss 64 on the second cam plate 31 now passes beneath the cam follower roller 63 to actuate the feed lever 61 so as to cause the feed discs 49 to rotate forwardly to force the next succeeding work piece onto the injection carriage. The oncoming work piece engages the finished piece and forces the latter into the finished work chute 20 for delivery to any suitable receiver.

The finished diameter can be regulated by adjustment of the limit screw 38. The transverse position of the work piece between the wheels 11 and 12 can be regulated and preset by adjusting the end abutment work stop 70. Adjustment for various diameters of work piece can be made by adjustment of the carriage feed screw 15. A knob 89 on the speed reducer 27 provides means whereby the entire operating mechanism may be rotated by hand for testing and adjusting the various movements.

While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, Within the scope of the appended claims, Without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is:

1. A work-piece feeding and ejecting device for a centerless grinding machine of the type having a grinding wheel, a feed wheel, and a work rest positioned between said wheels, comprising: a fixed bearing plate secured to said grinding machine at one side of and below said work rest; a pair of bearings mounted on said bearing plate on horizontal axes and in horizontally aligned, spaced-apart relation; a swinging parallel link journalled in and arising from each bearing; a horizontal injection carriage hingedly mounted on the upper extremities of both links in parallel relation to the axes of said grinding wheel and said feed wheel and intermediate the latter axes; work-supporting members carried by and extending forwardly from said carriage; and means for swinging said links to carry said work-receiving members from a work-piece-receiving position at one side of said wheels to a work-piece-depositing position between said wheels 2. A work-piece feeding and ejecting device for a centerless grinding machine as described in claim 1 in which the work-supporting members comprise two transversely spaced-apart plates between which the work piece is adapted to be supported, the space between said plates being unobstructed at one extremity so that said plates may swing over and on each side of the work rest to deposit the work piece thereon.

3. A work-piece feeding and ejecting device for a centerless grinding machine as described in claim 2 having a work-feeding mechanism, said plates being positioned so that when the parallel links are swung outwardly, they will be positioned alongside said feeding mechanism; and means in said feeding mechanism for feeding a work piece between said plates while simultaneously forcing the preceding work piece from between said plates.

4. A work-piece feeding and ejecting device for a centerless grinding machine as described in claim 3 having an adjustable stop means on said injection carriage for presetting the longitudinal position of the work piece along said plates.

5. A work-piece feeding and ejecting device for a centerless grinding machine as described in claim 4 having an inclined work piece chute positioned to discharge work pieces into said feeding mechanism by gravity; and means in said feeding mechanism for restraining a row of work pieces in said chute while one of said pieces is being deposited between said plates.

6. A work-piece feeding and ejecting device for a centerless grinding machine as described in claim 5 in which the restraining means comprises: two parallel, rotatable discs, each of said discs having a work piece receiving notch aligned with a similar notch in the other disc; and means for simultaneously rotating said discs so that said notches will carry a work piece from a row of work pieces in the work piece chute to the plates of said injection carriage, while the remainder of the peripheries of said discs restrain the remainder of said work pieces in said chute.

7. A work-piece feeding and ejecting device for a centerless grinding machine of the type having a grinding wheel, a feed wheel, and a work rest positioned between said wheels, comprising: an injection carriage; means for swinging said carriage to a position between the grinding wheel and the feed wheel of said machine; work-supporting means carried by said injection carriage and adapted to position a work piece on the work rest between said wheels; swinging links supporting said carriage; an injection shaft connected with one of said links to swing the latter and a motor-driven cam mechanism connected to rotate said injection shaft to motivate said injection carriage.

8. A work-piece feeding and ejecting device for a centerless grinding machine as described in claim 7 in which the cam mechanism comprises: a rotatable cam disc; a face cam track on one face of said disc; an injection lever; a cam follower roller on said injection lever adapted to follow said face cam track; and a connecting 7 bar connecting said injection lever with said feed mechanismfor actuating the latter in consequence of the rotation of said cam disc.

9. A work-piece feeding and ejecting device for a centerless grinding machine as'described in claim 8 having rotatable notched discs positioned in said feed mechanism to receive work pieces in their notches and deposit said pieces on said carriage; a second cam member on the oppositev face of said rotating cam disc; a feed lever in the path of and actuated by said second cam member; and an extensible connecting rod connecting said feed lever with said feed discs for rotating the latter in consequence of the rotation of said cam plate.

10. A work-piece feeding and ejecting device for a centerless grinding machine as described in claim 9 including resilient means incorporated in said connecting rod to allow extension of said rod should rotation of said discs be prevented.

11. A work-piece feeding an ejecting device for a V 'centerless grinding machine of the type having a grinding wheel, a feed wheel, and a Work rest positioned between said 1 wheels, comprising: a bearing plate; means for securing said bearingplate to said machine; a pair of a parallel, upwardly-extending, hinged links arising from said bearing plate; an injection carriagehingedly mounted on said links in a horizontal position, said links being positioned to rotate to a position between the feed wheel and the grinding wheel; work-supporting plates projecting horizontally in parallel relation from said carriage toward said wheels and adapted to receive a work piece therebetween, said plates being spaced apart so that when .said carriage is swung toward the work rest, said plates will pass on the opposite sides of the rest to deposit the work piece on the rest; hooked members on said plates positioned to engage the work piece and pull the latter a the opposite side of said plates from said feeding devices so as to receive the finished work pieces as they are forced r from said plates by said feeding device. 7 Y

12. A work-piece feeding and ejecting device for a centerless grinding machine as described in claim 11 having an inclined work feed chute; means for detachably securing said chute to said feeding device to feed work pieces'into the latter, said work chute consisting of parallel track bars along which the pieces are adapted to roll; and side plates for guiding the pieces along the track bars. 13. A work-piece feeding and ejecting device fora centerless grinding machine as described in claim 12 having supporting members secured to' and extending downwardly from said feed chute; and supporting rollers positioned to receive said supporting members so as to support said chute in an inclined position adjacent said feeding device. 7

References Cited in the file of this patent UNITED STATES PATENTS 7 Meyer Sept. 29, '1953 Norton Oct. 28, 1930

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