US2750715A

US2750715A - Steady rest and indicator gauge assembly for shaft grinder

Info

Publication number: US2750715A
Application number: US350040A
Authority: US
Inventors: Roy A Farnam
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-04-21
Filing date: 1953-04-21
Publication date: 1956-06-19
Anticipated expiration: 1973-06-19

Description

Jun 19. 9 R. A. FARNAM STEADY REST AND INDICATOR GAUGE ASSEMBLY FOR SHAFT GRINDER 3 Sheets-Sheet 1 Filed April 21, 1955 IHWHI lgl lull! 42 W .INVENTOR;

ROY A. FARNAM BY V ' ATTORNEY A. FARNAM 2,750,715

June 19, 1956 STEADY REST AND INDICATOR GAUGE ASSEMBLY FOR SHAFT GRINDER 3 Sheets-Sheet 2 Filed April 21, 1953 v INVENTOR. ROY A. FA'RNAM ATTORNEY R. A. FARNAM STEADY REST AND INDICAT June 19, 1956 OR GAUGE ASSEMBLY FOR SHAFT GRINDER 3 Sheets-Sheet 3 Filed April 2. 1953 mm mm I INVENTOR. ROY A. FARNAM ATTORNEY United States Patent STEADY REST AND KNDICATOR GAUGE ASEEEMBLY FOR SHAFT GRINDER Roy A. Farnam, La Grande, Oreg. Application April 21, 1953, Serial No. 350,040 6 Claims. (Cl. 51-405) This invention relates in general to the grinding of shafts and, in particular, to the grinding of the journal portions of a crank shaft of the type used in automotive vehicles and the like.

In such grinding, as is well known, the shaft is mounted at each end for rotation on the axis of the portion which is being ground and the shaft is then rotated while the rotating grinding wheel is maintained in contact with such shaft portion during the grinding operation. Since the grinding wheel bears against that portion of the shaft which is being ground, it is desirable to provide some additional support or steady rest for the shaft at this location to counteract any tendency for the shaft to be slightly bowed under pressure from the grinding wheel, also to eliminate any whipping or vibrating of the shaft during the grinding.

An object of the present invention is to provide an improved adjustable steady rest assembly for a shaft, particularly a vehicle crank shaft, during the grinding.

A further object of the invention is to provide improved spring-loaded means which will engage the portion of the shaft being ground and oppose the pressure exerted on such portion by the grinding wheel and which will remain in constant contact with the shaft regardess of any irregularities in the contacted shaft surface.

Another object of the invention is to provide a suitable gauge attachment in the steady rest assembly which can be adjustably set for cooperation with the shaft-contacting, spring-loaded means and which will constantly gauge the grinding effected by the grinding wheel.

These objects and other incidental advantages I attain through the combination and cooperation of the members of my steady rest assembly as hereinafter briefly described with reference to the accompanying drawings, in which:

Fig. l is a top plan view of a more or less standard type of crank shaft grinding machine illustrating my steady rest assembly mounted on the same;

Fig. 2 is a fragmentary section on line 22 of Fig. l but drawn to an enlarged scale and showing a side elevation of the entire steady rest assembly;

Fig. 3 is a fragmentary sectional elevation of the upper portion of the steady rest assembly of Fig. 2, drawn to a still larger scale;

Fig. 4 is a top plan view of the shaft-engaging bar of Fig. 3 and its positioning screw, showing the same by themselves and entirely removed from the housing;

Fig. 5 is a top plan view of the gauge of the assembly and its extension element, the latter being shown in section;

Fig. 6 is a fragmentary sectional elevation similar to Fig. 3 but illustrating an optional modified form in which the shaft-engaging bar and its positioning screw may be made; and

Fig. 7 is a top plan view of the shaft-engaging bar and the positioning screw of Fig. 6 showing the same by themselves.

Referring first to Fig. 1, an automobile crank shaft 10 "ice is shown supported between the head stock and tail stock of the grinding machine 11. A central journal portion of this crank shaft 10 is shown in position for grinding by the grinding wheel 12. The grinding wheel 12 of the grinding machine is mounted below the shield 13, the grinding wheel being axially adjustable in position, and the grinding wheel so arranged as to be rotated rapidly by suitable means (not shown) as is customary in grinding machines. My steady rest assembly, indicated in general by the reference character 14, is laterally slidable on the machine 11 and is shown in the proper position opposite the grinding wheel 12.

Referring now to Fig. 2, the steady rest assembly includes a housing 15 having a base portion which is slidably supported on a shoulder 16 extending longitudinally on the grinding machine 11 and is clamped in any desired location by simple clamping means. A hinged arm support 17 for the shaft 10 is pivotally mounted on a pin 18 and is raised into contact with the under side of the shaft 10 by adjustment of a screw 19, the inner end of which screw bears against the inner end of the arm 17 below the pin 18, as shown by the broken lines in Fig. 2. The arm 17 is tipped with Babbitt metal or with other relatively soft metal on the tip 17 so that the surface of the shaft 10 which is being ground will not be injured by its engagement with the bottom arm 17. This type of supporting arm is well known and is in general use.

A shaft-engaging bar 20 is slidably mounted on the upper portion of the housing 15 in such position as to enable the tip 20' of the bar to engage the shaft 10 on the opposite side from the grinding wheel 12. Consequently any pressure exerted by the bar 20 against the shaft 10 during the grinding operation will be in opposition to the pressure exerted by the grinding wheel 12 against the shaft 10.

The inner end of the bar 20 (Fig. 3) has a central channel 21 leading in from a larger end channel 22. A spring-loaded thrust element 23 has a stem 24 with an enlarged outer portion 25, the diameters of the stem 24 and enlarged portion 25 corresponding approximately to the diameters of the channels 21 and 22 respectively. A coil spring 26 extends around the stem 24 within the channel 22 with one end engaging the shoulder at the inner end of the channel 22 and the other end engaging the shoulder on the stem formed by the enlarged portion 25. An aperture 27 extends transversely through the bar 20 and a pin 28, carried on the stem 24, limits the travel of the stem 24, and thus the movement of the thrust element 23 with respect to the bar 20, by engagement with the wall of the aperture 27.

An adjusting screw 29, having threaded engagement with a bushing in the housing 15, and axially aligned with the stem 24 of the thrust element 23, and having an external finger knob 30 for convenience in adjustment, bears against the thrust element 23 as shown in Fig. 3, for the purpose of urging the bar 20 against the shaft 10 with desired resilient pressure. At the start of the grinding operation, with the housing of the steady rest assembly in position opposite the grinding wheel, the bar 20 is first moved towards the shaft by adjusting the screw 29 until the tip 20' of the bar contacts the shaft 10. Then the screw 29 is given slight additional rotation sufficient to bring the restraining pin 28 approximately to the center of the aperture 27. This causes the tip 20' of the bar 20 to press against the shaft 10 constantly during the rotation of the shaft 10 in the grinding operation, and enables the spring 26 to cushion and absorb the slight longitudinal vibrations of the bar 20 which would result from possible slight irregularities on the shaft surface. The spring 26 also enables the bar 20 to follow any' irregularities in the shaft surface and to continue to press against the shaft 10 in spite of the grinding of the shaft surface.

Calibrations (not shown) on the screw 29 and outside face of the threaded bearing for the screw enable the position of the pin 28 in the aperture 27 to be gauged when the bar 29 is adjusted inasmuch as the predetermined additional partial rotation of the screw 29, after the tip 20 of the bar 29 is first brought into contact with the shaft 10, will cause the pin 28 to move from right to left in the aperture 27 (as viewed in Fig. 3) until the pin 28 reaches the approximate center of the aperture. The tip 20 of the bar 20 is preferably formed with Babbitt metal or other relatively soft metal to prevent any possible marring of the surface of the shaft 10.

A post 31 (see Figs. 2 and 3) is slidably mounted on the forward end of the bar 20 and is secured in desired set position by the screw 32. A gauge, indicated in general by the reference character 33, is secured on the top of the housing 15' in the position shown in Figs. 2 and 3. This gauge 33 is of standard mechanical construction and the gauge housing has an extension 34 which contains a spring-loaded plunger 41 (Fig. which actuates the mechanism rotating the indicating finger or pointer on the gauge. A spring-biased thrust rod 35 extends through a cylindrical housing 36 which in turn is secured on the top of the housing by the

brackets

37, 37. A spring 38, extending around the rod 35, in the cylindrical housing 36, has one end in engagement With the bushing 39 in the end of the housing nearest the gauge 33 and the other end in engagement with a collar 40 secured on the thrust rod 35. Thus, as apparent from Fig. 5, the spring 38 tends to keep the thrust rod 35 moved to the left (as viewed in Fig. 5) to the extent permitted by the engagement of the fixed collar 40 with the adjacent end bushing. The cylindrical housing 36 is so positioned with respect to the gauge 33 that the thrust rod 35 and the plunger 41 of the gauge 33 will be in contact with each other at all times and thus will be in contact when the gauge reading is zero.

When the shaft-engaging bar is set so as to contact the shaft 10 and the adjusting screw 29 is manipulated, as previously explained, to cause spring pressure to be exerted on the shaft 20, the screw 32 is loosened and the post 31 is manually adjusted so as to move the thrust rod 35, and therewith the gauge plunger 41, sumciently to cause a predetermined reading to show on the gauge 33. Then the post 31 is clamped in this position by the set screw 32 and the entire assembly is ready for the grinding operation.

As the shaft 19 rotates, any irregularities on the shaft surface will produce slight endwise movements not only of the bar 20 but also of the thrust rod 35 and the gauge plunger 41, and these will be evidenced by movement of the pointer or indicating finger on the gauge. Thus the operator, by watching the gauge during the grinding, is constantly informed regarding the condition of the shaft surface which is being ground. Since the grinding wears away some of the shaft surface, this condition too will be properly indicated by the reduced reading on the gauge. In this way the operator can tell not only when surface irregularities on the shaft surface have been entirely removed but also exactly when the desired predetermined amount of the grinding of the surface has been completed.

In .Figs. 6 and 7 I show a slightly modified shaft-engaging bar and adjusting screw, which may be substituted for the bar 20 and adjusting screw 29 previously described. The modified bar 42 shown in these figures is solid throughout. The cooperating adjusting screw 43 on the other hand has a central channel 44 (Fig. 7) which extends inwardly from a larger end channel 4-5. A springloaded thrust element 46 has a stem 47, slide-able in the channel 44, and a larger diameter collar 48, slidable in the end channel 45. A spring 49 has its ends in engagement with the collar 48 and the shoulder at the inner termination of the enlarged channel 45 respectively. The stem 47 carries a pin 51 which engages the wall of the aperture 50 to limit the movement of the thrust element with respect to the screw 43. The tip 42' of this bar 42 is finished in the same manner as the tip 20 of the bar 20, and a post 31 is carried on the bar 42 in the same manner as the post 31 on the bar 20 and is clamped in desired position by the screw clamp 32. Obviously the operation is the same as with the bar 20 and its adjusting screw 29.

Minor modifications would be possible in my steady rest and indicator gauge assembly without departing from the principle of the invention. It is not my intention to confine my assembly to the exact details of construction herein illustrated and described, but the particular construction which I have illustrated and shown I consider to be the preferred manner of carrying out my invention. It is not my intention to limit my invention otherwise than as set forth in the claims.

I claim:

1. In a shaft grinding device including means for mounting and rotating the shaft and a rotary grinding wheel adapted to bear against the shaft during the grin ling operation, a steady rest housing, a shaft-en aging bar slidably supported in said housing and extending at right angles to the axis of the grinding wheel and adapted to extend at right angles to the shaft, located opposite the grinding wheel, said bar slidable towards and away from the shaft, means for urging said bar against said shaft, said means comprising a manually-operable positioning screw in axial alignment with the longitudinal center line of said bar and a spring-loaded thrust element interposed between said positioning screw and the portion of said bar opposite from the shaft-engaging end of said bar, a gauge, a post carried on said bar between the shaft-engaging end of said bar and said spring-loaded thrust element and adjustable thereon, and means con necting said post with said gauge, whereby when said bar is maintained in engagement with the shaft during the grinding all movement of said bar caused by said shaft will be indicated on said gauge.

2. In a shaft grinding device including means for mounting and rotating the shaft and a rotary grinding wheel adapted to bear against the shaft during the grinding operation, a steady rest housing mounted on said device, a shaft-engaging bar supported in said housing and extending at right angles to the axis of the grinding wheel and located opposite the grinding wheel, said bar slidable towards and away from the shaft, a spring-biased thrust element slidably mounted in the end of said bar opposite from the shaft-engaging end of said bar, means limiting the movement of said thrust element with respect to said bar, a manually-operable positioning screw for said bar engaging said thrust element, whereby said bar can be caused to press against the shaft with resilient predetermined pressure on the opposite side from the grinding wheel constantly during the grinding operation, a gauge mounted on said housing, a member carried on said bar and adjustable thereon, and means connecting said member with said gauge, whereby when said bar is maintained in engagement with the shaft during the grinding all movement of said bar caused by said shaft will be indicated on said gauge.

3. In a shaft grinding device including means for mounting and rotating the shaft and a rotary grinding wheel adapted to bear against the shaft during the grinding operation, a steady rest housing mounted on said device, a shaft-engaging bar supported in said housing and extending at right angles to the axis of the grinding wheel and located Opposite the grinding wheel, said bar slidable towards and away from the shaft, a positioning screw for said bar, a spring-loaded thrust element slidably mounted in the end of said positioning screw for engagement with the adjacent end of said bar, whereby said bar can be Caused to press against the shaft with resilient predetermined pressure on the opposite side from the grinding wheel constantly during the grinding operation, a

gauge mounted on said housing, a member carried on said bar between the shaft-engaging end of said bar and said spring-loaded thrust element and adjustable on said bar, and means connecting said member with said gauge, whereby when said bar is maintained in engagement with the shaft during the grinding all movement of said bar caused by said shaft will be indicated on said gauge.

4. In a shaft grinding device including means for mounting and rotating the shaft and a rotary grinding wheel adapted to bear against the shaft during the grinding operation, a steady rest housing mounted on said device, a shaft-engaging bar slidably supported in said housing and extending at right angles to the axis of the grinding wheel and opposite the grinding wheel, said bar slidable towards and away from the shaft, a manually-operable positioning screw for said bar, a spring-biased thrust element slidably mounted in the end of said positioning screw for engagement with the adjacent end of said bar, means limiting the movement of said thrust element with respect to said positioning screw, whereby said bar can be caused to press against the shaft with resilient predetermined pressure on the opposite side from the grinding wheel constantly during the grinding operation, a gauge mounted on said housing, a member carried on said bar and adjustable thereon, and means connecting said member with said gauge, whereby when said bar is maintained in engagement with the shaft during the grinding all movement of said bar caused by said shaft will be indicated on said gauge.

5. A shaft grinding device of the character described including means for mounting and rotating the shaft, a rotary grinding wheel adapted to bear against the shaft during the grinding operation, a steady rest housing mounted on said device and movable in parallelism with the axis of the grinding wheel, a shaft-engaging bar slidably supported in said housing and extending at right angles to the axis of the grinding wheel and positioned opposite the grinding wheel, said bar slidable towards and away from the shaft, a spring-biased thrust element slidably mounted in the end of said bar opposite from the shaftengaging end of said bar, means limiting the movement of said thrust element with respect to said bar, a manuallyoperable positioning screw for said bar engaging said thrust element, whereby said bar can be caused to press against the shaft with resilient predetermined pressure on the opposite side from the grinding wheel constantly during the grinding operation, a gauge mounted on said housing, an actuating element in said gauge, a member carried on said bar and adjustable thereon, and a spring- 6 loaded thrust rod connecting said member with said gauge actuating element, whereby when said bar is maintained in engagement with the shaft during the grinding all movement of said bar caused by said shaft will be indicated on said gauge.

6. A shaft grinding device of the character described including means for mounting and rotating the shaft, a rotary grinding wheel adapted to bear against the shaft during the grinding operation, a steady rest housing mounted on said device and movable in parallelism with the axis of the grinding wheel, a shaft-engaging bar slidably supported in said housing extending at right angles to the axis of the grinding wheel and positioned opposite the grinding wheel, said bar slidable towards and away from the shaft, a manually-operable positioning screw for said bar, a spring-biased thrust element slidably mounted in the end of said positioning screw for engagement with the adjacent end of said bar, means limiting the movement of said thrust element with respect to said positioning screw, whereby said bar can be caused to press against the shaft with resilient predetermined pressure on the opposite side from the grinding wheel constantly during the grinding operation, a gauge mounted on said housing, a plunger in said gauge, a post carried on said bar and adjustable thereon, and a spring-loaded thrust rod connecting said post with said gauge plunger, whereby when said bar is maintained in engagement with the shaft during the grinding all movement of said bar caused by said shaft will be indicated on said gauge.

References Cited in the file of this patent UNITED STATES PATENTS 732,314 Norton June 30, 1903 1,078,561 Shearer Nov. 11, 1913 1,299,838 Keller Apr. 8, 1919 1,317,227 Scusa Sept. 30, 1919 1,394,324 Matthews Oct. 18, 1921 1,615,060 Arnold Jan. 18, 1927 2,099,161 De Leeuw Nov. 16, 1937 2,160,378 Balsiger May 30, 1939 2,419,406 Koebbe Apr. 22, 1947 2,525,364 Mennesson Oct. 10, 1950 FOREIGN PATENTS 121,859 Sweden Sept. 5, 1946 OTHER REFERENCES Publication: American Machinist, March 11, 1948, page 187.