US2618910A - Guide bar attachment - Google Patents

Description

H. O. CADMAN GUIDE BAR ATTACHMENT Nov. 25, 1952 5 Sheets-Sheet 1 Filed Nov. 9, 1949 Nvsm-rom/ @-lcxva .fel 0. CCldYnC/m fw. mg

Nov. 25, 1952 Filed NOV. 9, 1949 H. O. CADMAN GUIDE BAR ATTACHMENT 3 Sheets-Sheet 2 INVBNTOY`, QJClr'oId 0. Codmm M ag,

Nov. 25, 1952 H. o. cADMAN GUIDE BAR ATTACHMENT 3 Sheets-Sheet 5 Filed Nov. 9. 1949 A41 wm VIL NVD N'TY5`-, WQY'Q d 0. Cox dma n dum, @5M MJ, W44.

Patented Nov. 25, 1952 UNITED STATES PATENT OFFICE 2,618,910 BAR A'r'r'Aonn/NT Harold-0. Cadinan, Rockton; lll.;g.assignor,' by

.msn'e assignments, to Gard-ner Machine Com'- pany,-a^crporationof Illinois Atpiiatit Novf 9, 1949, "seal-'N5'. '126,317.6 a claims. (ci. 51--151L-iy The present' invention pertains generally vtor through the vwork -zone` of Va'grin'd lingmachine,-

resort is commonly had vto lthe* -use of a pai-r of laterally spaced guide bars having a thickness Asubstantially less than tlied-istance'between the abrasive wheels. The thicknes'softhe guide bary in such instances may run as low as '22' Under normal operating'conditions, even vslight contact between they abrasive wheels and -e'ither of such thin guide bars would produce sufficient frictional heat to 'progressively distort the bar, resulting almost immediately in the severing of the bar with consequent spillage-of the workpieces and shutdown of 'the machine. Heretofore, it has been customaryto adjustably attach the guide lbars to a pair of rigidl posts,one-be-v ing located near thev entrance `and the other near the exit ofthe lgrinding- Zo'ne'. The initiala'dj-ustrnent is made such a i-n-an'ner' that the guidebars are tensioned -by tlie'inherent spring ofI these posts; Under high speed operation,

however, considerable'heating of the guidebars occurs and causes them `to expand proportionately. Forexample, a guide bar 26" in length may rise from room temperature to 300 F. during the grinding operation, resulting ina total linear expansion of as much a'.050 Since the springiness of the rigid supportingposts' is normally insuinc'ent to absorb this amount of expansion,

the tension of the guide bars' tends to slack on to an undesirable extentv consequent danger of contact with the grinding wheel and severance in the manner outlined above. Moreoverfth'e conventional type' mounting arrangiement is very apt to' producel unequal tensions in the guide bars whereby one bar may remain fairly taut and the'othermayA beso slack that it ifiexes excessively'. l Y

Accordingly, one object 'of the invention is to provide a guide bar attachment for av grinding machine and which willi havea' novel tensioning arrangement for the'-g'uidebars`, such-` arrangement being substantially unaiected by the thermal expansion of fthe `bars incident 'to operation of the machine. I

Another object is to provide`r an attachment of the' foregoing characterwherein thetensionl2 ing means, .after initialv ad-ustment, will maiintain the bars under .substantially equal 'tension for various operating conditions.

A further object is toprov'de .a bar' tensioning means of the type fse't .forth/'which will be of simple, rugged Vand economical constructionyet capable of 'adjustment with Va high degree of nicety and precision.

'Other objects andy advantages v'will become apparent as the following -detailed description proceeds, taken in' the'light of the accompanying drawings wherein:

Figure 1 is a fragmentary elevation oran illustrative guide bar attachment .embodying thev present invention, theabrasive wheeisiofa grinding machine and a portion of theirl housing being shown fragmentari-ly;

Fig. 2 is-a fragmentary plan View of the vdevice show-n in Fig. 1.

Figs. 3, 4 and 5 are enlarged transverseY sectional views through t-he illustra-tiveV guide bar attachment, such views being 'respectively taken in the plane of the lines :im-3,` 4-4 and 5 5 in Fig. 2.

Fig. 6 is an enlarged fragmentary plan View detailing one vof thespring members embodying the invention, togethervwith its supporting means.v

Fie- '1 is an enlarged fraementaryperspetve view showing details; o f thetensioningjspring end of the device of ll'ig v 1, one o ftheabrasive wheels being omitted for purposes of clearer illustra-1on- Fig. Sis anjenlarged iragmentary perspective View detailing in exploded; form the fastening means usedbetween one of the guide bar ends and its tensioning spring.

While the invention is susceptible of various modinca-tions rand alternative onstructions, -a preferred embodiment has been shown in the drawings and will be /describedbelow lin considerable' detail. It sh'ouldfbeY understood, l'1`c`iwe-ve1`,` that there is' no intention toiifit the .intention to the specific form disclosed, 'but on the contrary, the intention is te ctier an mkineatiohs and alternative" constructions falling within the spirit and scope of the invention as; expressed in the appended claims'.

Upon more specic reference t'oftheY drawings, it will be perceived that 'there' is shown' `an' illustrative guiderar attachment in embodying trie invention `and comprising `a pair 'of rigid' upstanding bed-plates yl I, I2 whichstraddle'a grin: 'ng zone donned lzietweenj'av pair o ania'ljl'yfspaced mountedY in any 'appropriate' manner uponv a grinding machine, the details of which are unimportant for present purposes. The abrasive wheels I 4, I5 are housed within a relatively heavy protective hood I6 fixed to the base of the grinding machine and having diametrically opposed mounting faces Il, I8 to which the bed-plates II, I2 are rigidly attached. Running through the grinding zone and having their end portions projecting through vertical slots I5 in the bedplates I2 are a pair of spaced apart parallel guide bars 23, 2|. As indicated in Fig. 4, the guide bars 2), 2| are of relatively thin strap stock, having a thickness which is only a fraction of the distance between the grinding wheels I4, I5 so as to provide clearance with the latter. When properly tensioned so as to eliminate any tendency for buckling or llexure, the guide bars 20, 2| define a workpiece supporting path running diametrically through the grinding zone.

Workpieces such as piston ring blanks R may be fed in a procession to the attachment I 0 by the use of an appropriate feed mechanism. While the details of such a mechanism form no part of the present invention, there is shown merely for the sake of completeness certain feed mechanism guide members which terminate at the attachment I0. As indicated in Figs. 1, 2 and 3, such members may comprise upper and lower guide rails 22, 24, respectively disposed in alignment with upper and lower guide bars 20, 2|. Located between the rails 22, 24 but spaced in straddling relation with the path of movement of the workpieces are a pair of side guides 25, 26. The latter arerigidly xed as by means of bolts 28 to a pair of mounting flanges 29 (Fig. 3).

Each of the flanges 29 is integral with a corresponding plunger 30 slidably supported in a head 3| projecting from the face of the plate I. Each of the plungers 3|), together -with its respective one of the side guides 25, 26 may be adjusted laterally of the path ofworkpiece movement as by means of an adjusting knob 32.

For the purpose of supporting the ends of the guide bars 20, 2| projecting through the bedplate against longitudinal movement while permitting adjustment of the same laterally relative to each other, the bed-plate I I is formed with a flat way 34 extending vertically thereof (Fig. 3). Slidably mounted on the way 34 are a pair of anchor blocks 35 which are supported by means of a common adjusting screw 3,6. The latter is journaled in ear 31 xed to the plate I I and threadedly engages aligned bores in each of the blocks 35. The upper portion of the screw 36 is threaded in the opposite sense from its lower portion. Consequently, rotation of the screw 36 by means of its adjusting knob 3S in one direction will cause the blocks 35 to move toward each other while rotation of the knob 38 in the opposite direction will cause the blocks to move away from one another. Pivotally secured as at 39 to the upper anchor block 35 is the left hand end portion of the upper guide bar (as viewed in Fig. 1). By the same token, the left hand end portion (as viewed in Fig. 1) of the lower guide bar 2| is pivotally xed to the lower anchor block 35 as at 45. When the end portions of the guide bars 20, 2| have been properly positioned by shifting the anchor blocks 35 through the use of the screw 36 and adjusting knob 38, the adjustment may be preserved by clamping the anchor blocks 35 against movement along the way 34. This is accomplished in the present instance by the use of a T-slot 4| eX- tending longitudinally of the way 34 and adapted to receive the heads of clamping bolts 42 carried by the blocks 35. Each of the bolts 42 may be clamped simply by tightening its nut 44.

In order to provide a corresponding lateral adjustment for the opposite end portions of the guide bars 20, 2|, the bed-plate I2 is provided with a vertical way 45 similar to the way 34 (Figs. 1, 2 and 5). A pair of anchor blocks 45 is slidably supported on the Way 45 by means of a screw 41 similar to the screw 36 and rotatably mounted in ear 48 fixed to the plate I2. The blocks 46 may be sifted toward or away from one another simply by turning adjusting knob 49 of the screw 41 in the proper direction. To clamp the blocks 46 in a desired condition of adjustment, the way 45 has a T-slot 5|) which receives the heads of clamping bolts 5| carried by the anchor blocks 45.

Means is provided for maintaining each of the guide bars 2|), 2| under sufcient tension to prevent ileXure, regardless of the degree of thermal expansion incident to the grinding operation. This is accomplished by interposing an individual tensioning means between one end of each guide bar and its supporting member, either directly or by the use of an appropriate mechanical connection, such means being adapted to exert a substantially constant tension regardless of the degree of thermal expansion in its corresponding guide bar. The opposite end of each guide bar is, of course, constrained against longitudinal movement relative to the other supporting member. Accordingly, in the attachment I0 the end of each of the guide bars 20, 2| projecting through the bed-plate I2 is connected to its anchor block 45 by means of a well loaded tension spring 52 having a comparatively high spring scale. `In the present instance, each of the springs 52 comprises a relatively heavy bar of resilient stock bent into a general U-shape. One arm of the spring abuts against its associated anchor block 45, being secured thereto as by means of the clamping bolt 5|. The other arm of the spring is adapted for attachment to the adjacent end of its corresponding guide bar. As shown in Figs. 7 and 8, such attachment means may include an integral lug 54 of reduced cross section which extends into a slot 55 near the end of the guide bar. To preclude tearing of the metal between the slot 55 and the end of the guide bar, a slotted reinforcing shoe 53 may be provided. In attaching the guide bar to the spring 52, the shoe 53 is first inserted into the slot 55 and pushed toward the end of the bar. The parts are s0 proportioned that this will leave just sufcient clearance to comfortably insert the lug 54 between the bottom of the shoe 53 and the far wall of the slot 55.

By reason of the foregoing structure, it will be apparent to those skilled in the art that a thermal expansion or contraction in one of the guide bars of as much as .059 will produce only a slight deflection of its spring 52. Moreover, due to the fact that the spring 52 is designed to operate in a substantially loaded condition, such deflection will have an almost negligible effect upon the tension in the guide bar. In addition, if the guide bars 25, 2| have been initially set up with substantially equal tension, unequal expansion or contraction in the bars will have little if any effect upon their relative tensions.

To provide a convenient means for relieving the tension in the springs 52 so as to facilitate assembly and disassembly of the guide bars thereon, a machine screw 56 is threaded onto each of the anchor blocks 49 and passes through aligned transverse holes in the arms of each spring 52. Tightening of the screw 56 will of course cause its head to force the longer spring arm toward the shorter arm and the spring tension force will thereupon be transferred to the screw 56. This arrangement normally produces sufficient deflection of each spring 52 to permit the slotted end of its associated guide bar to be readily slipped over the lug 54. Under normal operating conditions, however, the screw 56 is backed off to a point where there is considerable clearance between its head and the spring arm (Fig. 6). Under such circumstances, the guide bar alone carries the spring tension. Where a high degree of tension is desired in the guide bars, it may be found convenient to interpose a supplementary compression spring 58 between the arms of each of the springs 52. In such installations, the screw 56 constitutes a convenient guide for the spring 58.

Where the attachment I6 is mounted with its guide bars 20, 2| disposed in a substantially horizontal direction, it might be necessary to resort to side guides 59, 66 adjacent the plate l2. These elements straddle the path of movement of the workpieces and are substantially similar to the side guides 25, 26 described earlier herein. Like the latter, the side guides 59, 66 are carriediby plungers 6| slidably housed in heads 62 projecting outwardly from the bed-plate I2. The guides 59, 60 may be adjusted as by means of knobs 6,4, similar to the knobs of the guides 25, 26.

I claim as my invention:

1. The combination of a grinding machine having a work zone dei-ined between a pair of axially spaced abrasive wheels with a guide bar attachment comprising a pair of upstanding bed-plates rigidly mounted with one adjacent the entrance end and with the other adjacent the exit end respectively of the work zone, each of said bedplates having a vertical way with a T-slot therein, two pairs of spaced apart anchor blocks, each pair being disposed to slide along the way of a respective one of said bed-plates, vertical adjusting screws disposed in threaded engagement with respective pairs of said blocks and adapted to position the blocks of either of said pairs at various selected distances apart, clamping means engageable with the T-slots for securing said pairs of anchor blocks in desired conditions of adjustment, a pair of relatively thin normally flexible guide bars disposed in spaced relation and extending through the work zone and between said bed-plates, said guide bars being disposed in substantially perpendicular relation to the vertical Ways of said bed-plates, means pivotally securing the two ends of said guide bars adjacent one of said bed-plates to the anchor blocks of said one bed-plate, and substantially U-shaped tensioning springs connected between the opposite ends of said guide bars and correspending ones of said anchor blocks on the other of said bed-plates, each said spring being mounted with one leg fixed to its associated anchor block and the other leg disposed for the application of tension longitudinally of its associated guide bar.

2. In a guide bar attachment adapted for supporting a procession of Workpieces passing through the work zone of a grinding machine, the combination of a U-shaped guide bar tensioning spring having an extension at one end thereof for insertion in a slot adjacent the end of a guide bar, a reinforcing shoe also insertable in the slot and adapted to abut said extension, a compression screw mounted transversely of said U-shaped spring and adapted when tightened to relieve the initial tension therein, and a supplementary compression spring disposed in surrounding relation upon said screw, said supplementary spring being interposed between the ends of said U-shaped spring to augment the tension produced by the latter in the guide bar.

HAROLD O. CADMAN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 522,375 Ives July 3, 1894 537,117 Ives Apr. 9, 1895 1,384,756 Hambuechen July 19, 1921 1,416,952 Gardner May 23, 1922 1,862,894 Hughes June 14, 1932 2,169,252 Koether Aug. 15, 1939 2,209,711 Young July 30, 1940

Images