USRE16141E - Inteknal-gbinding machine - Google Patents

Description

' J. G. MDONOUGH INTE RNAL GRINDING MACHINE 15 Sheets-Sheef 1 original Filed on: 31, 1921 v gwuenl'oz 6', m gponou abbey: m1;

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' G. M DONOUGH INTERN L GRINDING MACHINE ONiginal Filed Oct. 31, 1921 1S Sheets-Sheet 15 rlllllllllllI/l Reissued Aug. 11, 1925.

uniT-ED STATES PATENT OFFICE.

INTERNAL-GRINDING MACHINE.

Original No. 1,497,574, dated June 10, 1924, Serial 161"511516, filed October 31, .1921. Application for reissue filed January 21, 1925. Serial No. 3,884.

To all whom it may concern:

Be it known that I, JOSEPH G. MCDON- oUGn, a citizen of the United States, resident of New Orleans, Orleans Parish, State of Louisiana, have invented certain new and useful Improv ements in InternaLGrinding Machines, of which the following is a specification.

My invention relates to machines for grinding the internal surfaces of metal cylinders, sleeves, gears, bushings, and the like commercial articles and the general object of the invention is to provide a machine that is capable of turning out rapidly and cfiiciently products of'this class in cylindrical, conical and other forms, ground and finished uniformly to within the closest limits of the predetermined finished diameters, and that will automatically cease the grinding operation when this diameter has been attained or announce the fact to the operator, or both, and that will, furthermore, indefiiitely continue this operation with the same accuracy and uniformity of output regardless of the wearof the grinding wheel.

More specific objects of the invention are:

First: To prevent the usual bell mouthing which consists in a perceptible outward fiarc at the ends of the internal cylindrical surface being ground, due to the necessity of repeated withdrawal of the grinding wheel from the cylindrical bore for the purpose of calibrating the internal diameter or introducing a gage plug.

Second: To eliminate the usual so-called sagging resulting in inaccurac of the work and due to overhanging wor -holding chucks or other fixtures in the ordinary horizontally operating internal grinding machines.

Third: To do away with the necessity of measuring the work during the progress or at the finish of the grinding, while at the same time automatically obtaining vwithin close limits extremely accurate results in finished measurements.

Fourth: 'lo automatically preserve practically the same high degree of accuracy both when grinding dry or wet or when grindingat dilfercnt or varying temperatures. -1n the ordinary practice of gaging the work, the varying temperature of the pieces ground when gaged results in inaccurate measures when the work cools off to normal temperature after grinding.

Fifth: Toaccelerate the work and reduce the attendance necessary by automaticallystarting the grinding of a piece at an increased or heavier speed to remove more stock for each passage of the grinding wheel through the piece and then automatically reduce the feed to remove less stock during the final finishing operations.

Sixth: To make the feeds positive to the predetermined degree of feed by preventing the usual lost motion or play in the feed mechanism.

Seventh:- To provide a machine of the multiple spindle type that will require but little attendance and that by its large ca pacity and rapidity and accuracy of action will enable the user of the machine to manufacture the finished articles cheaply and economically.

Other objects of the invention will appear from the followin detailed description of the invention by reference to the accompanying drawings.

In the accompanying drawings forming part of this specification,

Figure 1 is a side elevation, partly in section, of a machine embodying my invention,

Figure 2 is a plan and sectional view of a multiple spindle machine embodying my invention, and consisting of six spindle units, four of these units being removed and the left hand unit being shown in horizontal section on the line 2" and the right hand unit section on the line 2 of Figure 1,

Figure 3 is a front elevation of one of the spindle units,

Figure 4 is a rear elevation of one of the spindle units,

Figure 5 is a horizontal sectional view on the line 5-5 of Figure 4,

Figure 6 is a side elevation on a larger scale of one of the spindle units, showing the spindle carriage in a lowered position,

Figure 7 is a ccntralvertical section of the spindle unit as shown in Figure 6,

Figure 8 is ahorizontal section on the line 88 of Figure 1, showing the feed screw mechanism,

Figure 9 is a vertical section on the line 9-9 of Figure 8,

Figure 10 is a vertical section of the feed screw operating mechanism, the section be ing taken on the line 10-10 of Figure 12,

Figurell is a vertical section on the line ll-llof Figure 10,

Figure 12 is a similar section on the line 12-12 of Figure 10, illustrating the electrically controlled feed mechanism,

Figure 13 is a partial sect-ion on the line 13-13 of Figure 10, illustrating the adjusting means for the feed,

Figure 14 is a vertical section through the gage supporting chuck spindle and electric control housing below the spindle,

Figure 15 is a section on the line 15-15 of Figures 14 and 16,

Figure 16 is an enlarged section on the line 16-16 of Figure 14,

Figure 17 is a section on the line 17-17 of Figure 14,

Figure 18 is a section on the line 18-18 of Figure 19, of the spindle chuck for bold ing the pieces to be ground and illustrating the method of gaging the work,

Figure 19 is a plan view of the chuck, partly in section, on the line 19-19 of F igure 18,

Figure 20 is an enlarged vertical section of the switch box shown in Figure 14 for controlling the vertical movements of the grinding wheel and its carriage,

Figure 21 is a cross section on the line 21-21 of Figure 20,

Figure 22 is a detail view of the carriagecontrolling clutch-mechanism, illustrating in v and work when grinding a tube and diagrammatical form the electrical connections between the clutch mechanism and the switch box,

Figure 23 is a detail of the adjustable trip blocks,

Figure 24 is a vertical section of the grinding wheel and stationary guard, illustrating the relative position of the gages automatically changing from a coarse to a fine feed, the grinding wheel being indicated as moving upward,

Figure 25 is a plan view of Figure 24,

Figures 26 to 31 inclusive illustrate modified forms of gage pins and means for securing said pins in accurate positions in the gage post,

Figure 31 shows a form of when grinding short articles,

Figure 32 is a perspective view generally preferred form of Figure 33 is a diagrammatical view, illustrating the general automatic control and operation of the machine,

Figures 34, 35 and 36 are similar views, illustrating the automatic electrical control of the spindle carriage and showing the parts in different positions,

gage pin used of the gage pin,

spindle may readily be ground perfectly concentric to the bearings after fastening,

Figure 39 shows a modified form of gage post and means for protecting the post from water when used in a horizontal grinding position.

The driving and grinding mechanism.

In Figures 1 and 2 I have illustrated my invention as comprising a multiple spindle machine, but it will be understood that the claims of the invention are not confined to this construction, as each spindle section in itself is a complete, self-contained grinding unit capable of independent operation.

\Vhile I have illustrated in the drawings a multi-spindle grinding machine of a circular type, it will also be understood that the grinding spindles may be arranged in banks or rows or any other convenient form and that theinvention is not confined to the multi-spindle feature but is mainly embodied in the novel construction and operation of each of the single grinding units.

Referring first to Figures 1 and 2 for an illustration of the construction and operation of the multiple spindle feature of the machine, it will be noted that the base frame 20 supporting the structure comprising the six spindle units is rotatable upon the circular track 21 of the main bed frame 22. Integral arms 23 project from the base frame 20 to which are secured vertical brackets 24 carrying at their upper ends flanged rollers 25 adapted to roll on the track 21 and support the whole operating structure. A beveled ring gear 26 is rigidly secured to the Vertical brackets 24 and meshes with a beveled pinion 27 carried b a shaft 28, that is journaled in suitable bearings in th housing 29 and is also provided with a friction disc 30. A driving shaft 31, having a wheel 32 in frictional engagement with the disc 30 and a driving pulley 32, is

journaled transversely to the shaft 28 in with the rack 39. Motive power may be applied from any suitable source to the drivmg pulley 32 which will transmit motion I through the shaft 31 and friction members 30 and 32 to the shaft 28. Suitable planet'ary' reduction gearings 43 may be arranged in connection with the shaft 28, but this as well as the driving mechanism above debeveled pinion 27 rotate, the base frame 20 and the superstructure carried by it will be caused to rotate by means of thering gear 26 and that the rotat' speed of the structure may be varied as esired by operating the hand wheel 41, sliding rack bar 38 and thereby adjusting the friction wheel 32 on the frlction face of the disc 30, to any desired position. The mechanism comprising each of th grinding units is mounted in the vertical frames or columns 44, that are at the bottom secured to the base frame or plate 20, preferably by bolts or screws 45, and are rigidly secured together at the top by the spider plate 46 and screws 46".

intermediate frame or housing 47 is secured to the vertical frame members 44, preferably by lugs 47' and screws 48, and a central or a master shaft 49 is journaled in this frame below and has bearings 50 above in the spider plate '46. This shaft 49 may be driven in any suitable manner, preferably by an electric motor (not shown) and drives the entire mechanism of all the grinding units through suitable speed change gearing 51 in the housing 47. As the construction and operation of all the grinding units operated'by this master shaft are identical,

the following description pertains equally to all the units.

A vertical shaft 52 provided with speed change gearing 53, meshing with the gearing 51, is mounted in bearings in the housing 47 and carries at its lower end a pulley 54, the function of which will hereinafter appear. The speed-change for this shaft is effected preferably by means of a sliding key (not shown) in the shaft 52 operated through a rod 55 by a hand lever 56, but as this mechanism forms no art of the invention and any method 0 efi'ecting s eed changes from the shaft 49 to the sha t 52 may be employed, I have not illustrated the details of this speed change mechanism.

The column 44 is provided with horizontal V-flanges or tracks 57, accurately fit tingcorresponding riders 58 in a lateral feed block or saddle 59 by means of which said saddle is supported capable of a horizontal movement relative to the column 44. A hollow spindle 60 is journaled in bearings 61 and 62 upon abearing-head 59 adjustably secured to the saddle 59 ina'circular slot 61 (Fi re 9) by means of slot bolts 59 and carries a pulley 63 on ahorizontal line with the pulley 54. A series of flexible belts 64 pass'from the pulley 63 through a slot 65 in the column 44 around the pulley 54 by which the spindle 60 is started without shocks from the shaft 52 and rotated primarily from the master shaft 49.

The spindle 60 carries on its upper end a cylindrical chuck 66 supported on a flange 67 of the spindle and this chuck is provided with universal clamping means for accurately centering and holding the tube or other cylindrical work piece '68 or piece to be ground (see Figures 18 and 1 9). The clamping means preferably consists of three hardened clamping segments 69 removably 70 by screws 71. The work-piece 68, when inserted in the clamp ring, rests on a slightly protruding flange 72 at the bottom of the ring segments and these segments may be removed and others substituted of a different internal radius to fit different size tubes to be ground. The wedge blocks 70 '80 fastened to three segmental wedge blocks are formed externally conical, fitting the internalv conical surface 73 of the chuck 66 and when the tube 68 is to be inserted, the blocks 70 are raised, to spread or expand the ring segments 69, these segments being 1 under constant spreading tension by means of coiled springs 74 inserted in the end of the segments between their separated joints, (Figure 19). been inserted, all the segments comprising the clamp unit are forced downward, thereby uniformly contracting the ring segments and centering and securely clamping the piece in place. The vertical adjustment of the clamp members is preferably effected by means of an internally threaded sleeve 75 having a flange 76 engaging a circular groove 76 in the wedge blocks 70 and being in threaded connection with the external threads of the hub of a gear wheel 77 loosely mounted upon a central boss 78 of the chuck 66 for rotation, but held against vertical displacement by a ball 78 in an annular groove 78*. Spindles 79 carrying pinions 7 9 in mesh with the gear. wheel 77 are arranged in the rim of the chuck and project to the top thereof where they are provided with hexagon or equivalent shaped heads 80. By means of a wrench applied to any one of thespindle heads, the gear 77 may be rotated in either direction, thereby forcing the sleeve 7 5 and wedge blocks 70 up or down to release therefrom, or clamp the ring segments tightly'around the work piece 68 (Figures 18 and 19). The

grinding wheel 81, consisting of emery, car- 1 After the work-piece 68 has vertically in bearin s 84 and 85 arranged within a dust proo? housing 85 provi ed in a frame or carriage 86 that is vertically slidable in V-slots 87 in the column '44 (see Figure 2). The arbor 82 is provided at its upper end with'a driving pulley 88 and an anti-friction thrust bearing 89 and is driven at high s eed from the master shaft 49 by means 0 a pulley 90 frictionally engaging a pulley 91 fastened to a vertical roller pulley 92, said pulley being mounted upon a shaft 93 -having upper bearings 94 and lower adjustable bearings 95, arranged upon the column'44 (Figure. 1). A driving belt 96 runs from the roller pulley 92 through slots in the column 44 and around a small pulley 97 carried by. a 98 journaled in ball bearings 99 and 100 in a housing 101 integrally connected to the carriage 86 by a bracket or arm 102 (Figure 7). A larger pulley 103 is preferably cast integral with the small pulley 97 and a belt 104 runs from this pulley around the arbor pulley 88. Frictional tension is provided between the friction pulleys 90 and 91 by means of a coil spring 105 arranged in a socket 105 in the column 44 and tensioned against the bearing block 95, that is mounted for a slight lateral movement between the guide lugs 106 (see Figure 7). I prefer to provide means for temporarily throwing the friction wheels out of engagement consisting of a lever 107 pivoted on one of the guide lugs 106 and aving a pin 108 normally free of the bear ing block 95 but when the lever 107 is rocked towards the block by means of a rod 109 having a handle 110 (see Figure 2), the block" 95 may be moved slightly against the tension of the spring 105 to release the friction wheel 91 from the driving wheel 90 and sto'protation of the roller pulley 92.

In the operation of grinding a tube or cylinder to an exact predetermined internal diameter, the rotating grinding wheel is automatically and repeatedly passed downwards and upwards in grinding contact with a small arc of the internal surface of the cylinder until the predetermined internal diameter is attained. The chuck 66 containing the cylindrical work-piece to be ground simultaneously rotates in the opposite direction, driven by the belt 64. At the conclusion of either the downward or upward movement of the grinding wheel 81 or at both ends of the movement, as will be hereinafter described, the saddle 59 carrying the chuck 66 is automatically moved laterally in the direction of the grinding wheel to again bring the work-piece in active grinding contact with the grinding wheel.

When the piece has been finished tothe required internal diameter, the .grinding short spindle boss 118 concentric with the bearing. sleeve 119 having a forked projection 120 gear 134 (Figures 1, 4

wheel 81 is automatically raised to a higher plane above the chuck 66 and preferably continues to operate idly at the higher plane while the finished. piece is being removed and a fresh one inserted in the chuck 66- The vertical reciprocating movement in different planes of the carriage 86, carrying the arbor for .the grinding wheel 81, is obtained preferably by the hereinafter de scribed means. Referring to Figures 3. and 7, a screw shaft or Worm 111 is slidably mounted at its lower end in a lug 112 of the carriage 86- and is provided with a nut 114 below the lug 112. .The worm passes through an internally threaded hub 115, of a bevel gear 116 that is rotatably mounted in a bearing on the column 44, and is provided at the lower end of the hub with a thrust c'ollar 115; The carriage is provided at its upper end with a bracket 113 having a A slidably fits the boss 118 and a pin 121 passes through holes in the shaft 111 and sleeve 119 and through a slot 122 in the boss 118.

The forked end 123 of the projection embraces a lever 124 pivoted at 125 to a lug on the bracket 113 and having on its opposite end a slot 126 engaging a pin 127 that is carried by a vertical trip bar 128 supported in bearings 129 and 129 upon the carriage 86 and capable of a limited vertical adjustment. The screw shaft 111 is prevented'from rotating by the pin 121 and it will be seen that as the bevel gear 116 is rotated in the bearing 117 the shaft 111 will be moved vertically in the threaded hub of the gear 116 and that the carriage 86 will be moved up or down, accordingly as the gear is rotatedin one or the other directions Rotation is imparted to the gear 116 by the bevel gear 130 secured on a shaft 131 and meshing with the gear 116 and this rotation is automatically reversed at the end of each vertical movement of the carriage 86 by the following described mechanism. The shaft 131 to which the bevel gear 130 is secured is preferably rotatably mounted in a bearing 132 carried by a bracket 46 depending from the spider 46 and carries a larger spur gear 133 keyed thereto. This gear is in mesh with a spur and 5) keyed .or otherwise secured to a shaft 135 that is mounted in bearings 136 and 137 on the column 44 and carries bevel gears 138 and 139 running loosely thereon. The bevel gears 138 and 139 are in constant mesh with a small bevel gear 140 upon a shaft 141 journaled in bearings in the column 44 and provided at its outer'end with another bevel gear 142 in mesh with a similar car 143 upon a vertical shaft 144 having column 44 and provided at its lower end with a universal coupling 146 (see Figures 4 and7). A tumbler rod 147 connects this.

earings upon the t e speed change shaft 52. Through the above described transmission mechanism the bevel gears 138 and 139 are caused to rotate in opposite directions upon the shaft'135,

ese gears are provided with clutch teeth 138 and 139" respectively see Figures 5, 6, 22, 33, 34 and 36) and a c utch collar 152 having corresponding clutch teeth to in-. terlock with the teeth .138 and 139, isarranged between the gears 138 and 139 and is slidmgly splined to the shaft 135 to rotate therewith. It is obvious that if the clutch collar 152 is brought in engagement with the clutch teeth of the gear 138, the gear 116 will be revolved in a predetermined direction and if the clutch collar is connectedto the clutch teeth of the gear 139 the gear 116 will be revolved in the opposite direction and that the carriage 86 w1ll be moved in corresponding opposite vertical directions.

.Clutch connection is shifted alternately between the gears 138 and 139 caused by, the vertical-travel of the carriage 86by means of a bell crank lever 153 (see Figure 6) fulcrumed at 154 on the column 44 and engaging with considerable axial play an annular slot 155 in the clutch collar. The lateral arm 153" of the bell crank lever is alternately struck at the termination of the carriage travels, by tripblocks 156 and 157, thereby rocking the lever on its fulcrum and moving the clutch collar from connection with one .to the other of the ears 138 and139. The lever 153 is prefera 1y provided witha depending arm 158 engaged by a springpressed latch 159 slidingly arranged in abracket 160, the arm and latch having'beveled interlocking ends for tripping and holding the lever 153 in either extreme position with the clutch collar 152 in engagement with one of the gears 138 or 139. The trip blocks 156 and 157 are vertically adjustable on the bar 128 (Figure 23) to adjust the travel of the carriage to various lengths of grinding work. Adj ustment-of the travel of the carriage to close limits may be readily made by adjusting the actuating screws 1631 in the blocks 156 and 157.

I The lateral feed or setting up mechanism The work-carrying chuck 6.6 and chuck spindle 60, as above described, are mounted part of an inch to secure the 'required curacy, means are providedwhereb the net-' I ural slack in the motion transmitting screw;

is compensated for. I

Referring first to Figu'i' and 9, the feed screw200 is mounted in agr bearing in th'e column 44 and is provided with a drivingbevel gear 202,keyed to "the shank vof the screw and rigidl held against shoulder 1203 by a threa ednut 204. Thel flfi' faced back of the gear 202 {15 held to against the faced end of the bearing 201 by a coilsprin 205 arranged in a socket in the bearing an tensioned against a collar 206 held against longitudinal movement on the feed screw shank. The threads of the feed screw 200 fit internal threads in 9. lug 208 integral with the feed block 59 and also with the internal threads o'f-a-follower nut 209. This nut is 'free-toslide with the feed block but is prevented from turnin by bearingagainst a face 210 on the feed b ock.

A coil spring 211 is interposed between the lug 208 and nut 209 and keeps the threads of the lug against the drivingsideof the screw threads. The feed screw 200 is rotated by means hereinafter described to move the? feed block 59 in the direction of the arrow in Figure 8 when feeding the work against the grinding wheel and it will be seen that any play in the screw threads or back lash in the screw is effectually prevented by this construction. A ton e 212 (Figure 1) of the ring formed bearing block 59 projects into the circular groove of the feed block and by reason of this construction, the chuck-carrying spindle 60 may be readily adjusted for any desired alinement and secured in place by the clamping bolts 59 (Figures 8 and 9). The feed screw 200 is operated through a vertical shaft 213 mounted in bearings on one side of the column 44 and carrying at its lower end a small 'bevel gear 214 in mesh with the feed screw gear 202 and at-its upper end a bevel gear 215 (see Figures 3, 10 to 13) in mesh with a bevel gear 216 carried by a shaft 217. This shaft is mounted in bearings 218 in a bracket 219 that is fastened to the side of the column 44 (Figure 7 A handwheel 220 is keyed to the outer end of the shaft 217 and i 221. Between the yoke arms 221' and journaled therein, is a worm 222 provided with a knurled'finger rip 223. A sleeve 224 surrounds the sha 217 and this sleeve is provided at its outer end with a worm wheel

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