US3157091A

US3157091A - Feed mechanism

Info

Publication number: US3157091A
Application number: US159912A
Authority: US
Inventors: Mickas George
Original assignee: Michigan Tool Co
Current assignee: Michigan Tool Co
Priority date: 1961-12-18
Filing date: 1961-12-18
Publication date: 1964-11-17
Anticipated expiration: 1981-11-17
Also published as: GB962611A

Description

Nov. 17, 1964 Filed Dec. 18, 1961 G. MIC KA S FEED MECHANISM 3 Sheets-Sheet 1 fee 1 7%1' IN VEN TOR. 52w rye Mic/74 BY D ///W' Nov. 17, 1964 G. MICKAS 3,157,091

FEED MECHANISM Filed Dec. 18, 1961 5 Sheets-Sheet 2 Nov. 17, 1964 G. MICKAS 3,157,091

FEED MECHANISM Filed Dec. 18, 1961 :5 Sheets-Sheet 3 IN VENTOR. corye )/zb/d.s.

/ w yzw United States Patent 3,157,691 FEED MECHANISM George Mickas, Grosse Fointe Woods, Mich assignor to Michigan Tool Company, Detroit, Mich, a corporation of Delaware Filed Dec. 18, I961, Ser. No. 159,912 11 Qiahns. (Cl. 99-1) invention will become apparent from the subsequent description, taken in conjunction with the accompanying drawings.

In the drawings:

FIGURE 1 is a fragmentary top plan view, with parts shown in section along the line 11 of FIGURE 2, of a portionof amachine such as a gear shaper or finisher, showing the controls for utilizing the invention;

FIGURE 2 is a cross-sectional view in elevation taken along the line 2-2 of FIGURE 1 and showing the internal mechanism of the invention;

FIGURE 3 is a cross-sectional view in elevation taken along the line 33 of FIGURE 2 and showing cooperation between the wedges and the unit supporting column;

FIGURE 4 is a cross-sectional view in elevation taken along the line 44 of FIGURE 1 and showing the coarse or initial upfeed setting mechanism;

FIGURE 5 is a cross-sectional view in elevation taken along the line 5-5 of FIGURE 1 and showing the mechanism for setting the fine upfeed;

FIGURE 6 is a fragmentary cross-sectional view in elevation taken along the line 6-6 of FIGURE 2 and showing the manner in which the flats on the fine feed a nut flange engage their limit stops; and

FIGURE 7 is a fragmentary cross-sectional view taken along the line 77 of FIGURE 4 and showing the initial feed indicating dial drive.

In general terms, the illustrated embodiment of the invention comprises a first power-actuated wedge movable in one direction against adjustable stop means, with a second wedge being movable at right angles to the direction of movement of the first wedge and adapted to shift a tool supporting mechanism in one direction due to interaction between the inclined wedge surfaces. The stop means comprises a rod having one end threadably mounted in a rotatable nut, and an initial feed sleeve is slidably but non-rotatably keyed to the other end of this rod. Rotation of the initial feed sleeve will permit adjustment of the rod a predetermined distance from the initial position of the first wedge, so that movement of the first wedge into contact with the rod will result in'an approach feed shifting movement of the tool.

After the work has made one pass or a predetermined number of passes relative to the tool during a cutting cycle, the nut which is held against axial movement, may be rotated a predetermined angular distance, backing the rod a slight distance away from the wedge and thus resulting in a fine feed increment of movement of the tool, the wedge being constantly urged against the stop. Successive fine feed increments may thus be made after each pass, the amount of each increment being determined by an 3,1151%,fi9l Patented Nov. I7, 1964 adjustable stop which limits the movement of a pawl and ratchet used to rotate the nut. The nut is frictionally held in position after each incremental movement, and is spring-returned to its initial position when the frictional force is relieved at the end of the operation by backolf of the wedge. The mechanism is adapted for automatic control and could operate in conjunction with a counting unit which stops the fine feed after a certain number of cycles.

Referring more particularly to the drawings, a portion of a machine incorporating the invention is generally indicated at II, the machine having a housing 12 formed at its base with a knob supporting bracket 13 mounted on the forward portion of housing 12 and a removable cover 'plate I4 secured to bracket 13, cover 14 being removed in FIGURE 1. Machine 11 may, for example, be a gear finishing machine having a tool support (referred to as a knee) indicated schematically at 15 adapted to carry a tool 16 such as a gear shaving cutter beneath a workpiece I7, knee 15 being guided for vertical movement on the machine frame. Tool support 15 is mounted on a feed screw Ififlthe lower end of screw 18 being threadably mounted in a nut 19 secured to the upper end of a tubular support 21, this support being slidably mounted in a hollow column 22 formed in the housing. Feed screw 18 is rotatably but non-slidably secured to knee 15, and means indicated schematically at 23 are conventionally provided on the knee for manually rotating feed screw 18 with respect to nut 19, thereby raising or lowering knee 15 and tool 16.

.The novel feed mechanism of this invention is generally indicated at 24 and is disposed within housing 12. A recessed fiat surface 25 is formed on the forward side of column 22 at the central portion thereof, and a second recessed flat surface 26 is formed on support 21 flush with surface 25.

A wedge supporting block 27 is disposed within the recesses formed in column 22 and support 21. Block 27 is mounted on the lower surface 28 of the recess in column 22.

The shape of block 27 is best seen in FIGURES 2 and 3, the block having a horizontally extending recess 29 for the reception of a lower wedge 31, and a vertically extending recess 32 for 'the reception of an upper wedge 33. The two recesses 29 and 32 may thus be said to form an inverted T, except that the height of the right hand side of recess 29, as seen in FIGURE 2 is somewhat greater than the height of the left hand side, in order to accommodate wedge 31. Block 27 is secured to column 22 by pins 34, and the upper surface 35 of the recess in column 22 is spaced upwardly from the upper surface of block 27, as seen in FIGURE 3.

The fiat underside of lower wedge 31 is supported on a horizontal surface 36 at the lower end of recess 29 by means of anti-friction bearings 37, a pair of stops 3S and 39 being secured to opposite ends of wedge 31 to limit movement of the roller cage. The upper surface 40 of wedge 31 is inclined, and the lower surface 41 of upper wedge 33 is similarly inclined, anti-friction bearing means being disposed between these surfaces. Upper wedge 33 is guided for vertical movement by the side walls of vertical recess 32, and the fiat upper surface 42 of wedge 33 is engageable with the upper surface 43 of the recess in support 21. Horizontal movement of wedge 31 will thus result in vertical movement of wedge 33 and support 21, causing vertical movement of screw 18, knee 15 and tool 16. More particularly, leftward movement of wedge 31 in FIGURE 2 will result in upward feeding movement of tool 16, whereas rightward movement of wedge 31 will permit downward retraction of the tool.

A fluid-operated dual-acting cylinder 44 is mounted within housing 12 to the right of column 22, and a piston 45 extending from the cylinder is connected at 46 to the right hand end of wedge 31.

A feed adjusting screw 47 is mounted in housing 12 to the left of column 22, as seen in FIGURE 2. Screw 47 has a projection 48 engageable by a spherical member 49 carried by the left hand end of wedge 31, so that adjustment of member 47 along its horizontal axis will limit the leftward movement of wedge 31 and thus the upward movement of tool 16.

The means for supporting member 47 includes a bracket 50 mounted on a boss 51 within housing 12. A hearing support 52 is formed on the right hand end of bracket 58, as seen in FIGURE 2, a bushing 53 being carried by support 52. A sleeve 54 is rotatably mounted in bushing 53, and a key 55 connects sleeve 54 to the unthreaded right hand portion of screw 47. Axial movement of sleeve 54 is prevented by a shoulder 56 formed on the sleeve and engaging the left hand end of bushing 53, as well as by a worm gear 57 secured to the right hand end of sleeve 54 and engaging the right hand end of bushing 53, the bushing in turn having a shoulder 58 engaging the right hand end of bearing support 52. A keyway 59 in sleeve 54 permits axial movement of screw 47 with respect to sleeve 54.

Worm gear 57 is provided in order to permit setting of the initial upfeed of tool 16, and for this purpose an initial upfeed setting shaft 61 is provided, as seen in FIGURE 4. The upper portion of shaft 61 is rotatably supported at 62 by a portion of knob supporting bracket 13, and a setting knob 63 is secured to the upper end of shaft 61, this knob being exposed when cover 14 is removed. A worm 64 is secured to the lower end of shaft 61 and meshes with worm gear 57.

The left hand portion of screw 47 is threadably disposed within an adjusting nut 65, so that with nut 65 stationary, rotation of knob 63 will cause adjustment of screw 47 in a horizontal direction. A bearing support 66 is formed at the left hand end of bracket 50, a bushing 67 being fixed within this hearing support. Nut 65 is rotatably mounted within bushing 67. A limit stop 68 is mounted in the left hand portion of nut 65 for limiting the leftward movement of screw 47.

Means are provided for progressively rotating nut 65 to cause axial movement of screw 47 in relatively small increments for fine upfeed after initial upfeed has been accomplished. This means includes a ratchet 69 secured to the left hand portion of nut 65, and a pawl 71 engageable with the teeth on ratchet 69 so as to rotate the ratchet in a clockwise direction as seen in FIGURE 5. Pawl 71 is pivotally mounted by a pin 72 on a plate 73, this plate being rotatably mounted on bushing 67 to the left of bearing support 66 in FIGURE 2. A fluid actuated cylinder 74 carried by an extension 75 of bracket 50 has a piston 76 connected to pin 72, so that movement of piston 76 to the right from its FIGURE position will cause pawl 71 to engage and rotate ratchet 69, the pawl being urged into position by a spring 77. A member 78 is stationarily supported by housing 12 in the path of pawl 71 when the latter moves to its retracted position as seen in FIGURE 5, so that pawl 71 will be lifted away from ratchet 69.

A fine feed adjusting shaft 79 is rotatably mounted in housing 12 and bracket 13 as seen in FIGURE 5, the upper end of this shaft carrying a knob 81, with a ball detent 82 engageable with knob 81 to hold the knob in any one of four positions 90 apart, as marked on a panel 83 adjacent knob 81 and seen in FIGURE 1. These four positions will present different amounts of upfeed per stroke of work, that is, incremental feed movements of tool 16 with respect to work 17 after each pass of the tool with respect to the work.

An adjustable stop member 84 is secured to the lower end of shaft 79 and is adapted to cooperate with a projection 85 on plate 73. Stop 84 has four stepped surfaces of differing heights, each surface representing a different 4 position of knob 81. The feed movement of pawl 71 (to the right in FIGURE 5) will be limited by engagement of projection with that surface of stop 84 which is positioned in obstructing relation with the projection. The angular rotation of ratchet 69 and nut 65 will thus be similarly limited.

The right hand end of bushing 67, as seen in FIGURE 2, is provided with a pair of shoulders 86 and 87 extending axially from the upper and lower portions respectively of the bushing, these fixed shoulders being seen in FIG- URE 6. Nut 65 has a similar pair of shoulders 88 and 89 engageable with shoulders 86 and 87 respectively when nut 65 is rotated clockwise in FIGURE 6. A torsion spring 90 has one end secured to a fixed member 91 at the left hand end of bearing support 52, as seen in FIG- URE 2, and the other end secured to the right hand end of nut 65, spring 99 urging nut 65 clockwise as seen in FIGURE 6.

Shoulders 88 and 89 of nut 65 form flattened parts of a flange 92 on nut 65, and this flange has a radial surface frictionally engageable with the surface 93 on bushing 67 When piston 45 is urged to the left, the axial force exerted on nut 65 by screw 47 will be sufficient to hold nut 65 in the position into which it is rotated by the periodic advancement of pawl 71, despite the force exerted by spring 90. However, when the axial force on screw 47 is relieved by rightward withdrawal of wedge 31, spring 90 will return nut 65 to its original position in which shoulders 88 and 89 of the nut engage fixed shoulders 86 and 87 In operation, with work 17 and tool 16 in position, knob 63 will be rotated to adjust the axial position of screw 47 with respect to wedge 31 so that leftward movement of wedge 31 from its initial rightward position in FIGURE 2 will be sufficient to take up the backlash between the tool and workpiece. The amount of this initial upfeed may be determined in various ways, and an indicating dial 94 is provided for aiding the operator in this setting. This dial is carried by bracket 13 and is seen in FIGURE 7, the dial being mounted on a shaft 95 driven from shaft 61 through a worm 96 on shaft 61 which meshes with a worm wheel 97 on shaft 95. A window 98 is provided for viewing dial 94. During this setting of screw 47, nut 65 will be held against rotation by spring 90 and fixed shoulders 86 and 87.

Upon pressurization of the right hand end of cylinder 44, leftward movement of wedge 31 will take place, and will continue until spherical member 49 engages projection 48 on screw 47. The wedging action between wedges 31 and 33 will cause simultaneous upward movement of wedge 33, lifting support 21, nut 19, screw 18 and knee 15 which carries tool 16, so that the initial backlash between the tool and work is taken up.

After the first pass between the tool and the work has been completed, cylinder 74 will be actuated to cause rightward movement of pawl 71 in FIGURE 5, the pawl engaging ratchet 69 and causing rotation of nut 65, screw 47 being held against rotational movement by the fact that it is in effect keyed to worm wheel 57, the latter being held against rotation by worm 64.

The angular movement of ratchet 69 will be determined by engagement of projection 85 with the preselected surface of stop 84 as determined by the setting of knob 81. As nut 65 rotates, screw 47 will be moved a preselected distance to the left in FIGURE 2, and since piston 45 constantly urges wedge 31 to the left, tool 16 will be simultaneously moved upwardly the prescribed distance.

The tool and work will then make another pass relative to each other, pawl 71 being retracted by cylinder 74 to the position of FIGURE 5. The frictional engagement of flange 92 on nut 65 with surface 93 of fixed bushing 67 will hold the nut in its rotated position, despite the urging of spring 90.

After each successive pass between the tool and work,

pawl 71 will again be actuated for an additional fine upfeed of the tool. The timing and counting mechanism (not shown) may be so arranged as to provide a final series of passes between the work and tool during which no additional upfeed is imparted to the tool. After the finishing passes, cylinder 44 will cause rightward retraction of wedge 31, thus permitting downward retraction of tool 16 by the weight of wedge 33 and its supported parts. The rightward limiting position of wedge 31 may of course be preselected so as to control the initial upfeed distance.

As the axial pressure on screw 47 is relieved, spring 90 will cause clockwise rotation of nut 65, as seen in FIG- URE 6, until shoulders 88 and 89 of the nut engage fixed shoulders 86 and 87. Pawl 71 will not prevent such return rotation in view of its being lifted out of obstructing relation with ratchet 69 by member 73. The parts will then be in position for another cycle.

It should be observed that the automatic upfeed mechanism described above will not interfere with the functioning of the manual feed as shown schematically at 23.

While it will be apparent that the preferred embodime'nt herein illustrated is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. In a feed mechanism, a support, means guiding said support for rectilinear movement, threadably connected nut and screw members, means for adjustably holding one of said members in a predetermined angular position with respect to the other member, means holding said other member against rotation during adjustment of the adjustable holding means for said one member, means for successively rotating said other member through a plurality of angular increments while said one member is held by said adjustable holding means, means holding said other member against axial movement, and means operatively connecting said support to said one member, whereby said support will be movable in response to axial movement of said one member caused by adjustment of said adjustable holding means or by said successive rotation of said other member.

2. The combination according to claim 1, the means operatively connecting said support to said one member comprising a first wedge member, means supporting said first wedge member for movement in a direction parallel to the axis of said threadably connected members, means urging said first wedge member into engagement with said one member, a second wedge member, means supporting said second wedge member for movement in a direction transverse to the direction of movement of said first wedge member, and operatively connected inclined surfaces on said wedge members for transmitting motion of said first wedge member to said second wedge member.

3. In a mechanism for preselecting initial feed and successive fine feed increments for a machine tool support, a support shifting member movable in a rectilinear path, means for moving said support shifting member in opposite directions along said path, means responsive to movement of the support shifting member in one direction for causing feed movement of said support, a feed adjusting screw in obstructing relation with said support shifting member when moved in said one direction, a feed adjusting nut threadably mounted on said feed adjusting screw, means supporting said nut for rotational movementand restraining the nut against axial movement, means for normally maintaining said nut in a predetermined angular position, means for setting the initial spacing between said feed adjusting screw and support shifting member comprising a sleeve, means supporting said sleeve for rotational movement and restraining the sleeve against axial movement, means slidably but non-rotatably connecting said sleeve to said screw, and means for adjustably holdrocating said pawl, and adjustable stop means for preselecting the length of pawl stroke.

5. The combination according to claim 3, said means for maintaining the nut in a predetermined angular position comprising a stationary shoulder, a shoulder on said nut engageable with said stationary shoulder, and a spring rotatably urging said nut in a direction causing engagement of said shoulders 6 The combination according to claim 5, further provided with frictional means responsive to a force exerted by said support shifting member on said screw for holding said nut in each of its angularly shifted positions against the urging of said spring.

7. In a mechanism for preselecting the initial upfeed and the incremental fine upfeed for a machine tool support, a stationary vertical column, a support mounted in said column for vertical movement, a first wedge, means supporting said first wedge for horizontal movement in one direction from a retracted position, a second wedge in supporting relation with said support, means guiding said second wedge for movement in a vertical direction, operatively connected inclined surfaces on said first and second wedges whereby movement of said first wedge in said one direction will cause upfeed movement of said support, a feed adjusting screw having one end in obstructing relation with said first wedge when moved in said one direction, an inital feed adjusting sleeve slidably and non-rotatably connected to said screw, stationary means rotatably supporting said sleeve, means for adjustably setting said sleeve in a variety of angular positions, a feedadjusting nut threadably mounted on said screw, stationary means rotatably supporting said feed adjusting nut, a ratchet on said nut, a rockably mounted pawl engageable with said ratchet, engagement of the pawl with the ratchet when the pawl is moving in one direction causing rotational movement of the nut in a direction causing withdrawal of said screw from said first wedge, means for preselecting the operating stroke of said pawl, means constantly urging said nut in the opposite direction toward a predetermined angular position, and means responsive to a force exerted by said first wedge on said screw for maintaining said nut in its successive angularly shifted positions.

8. The combination according to claim 7, said means for constantly urging the nut toward a predetermined angular position comprising a torsion spring connected to the nut, a stationary shoulder, a shoulder on said nut engageable with said stataionary shoulder for predetermining said angular position, said means for holding the nut in its successive shifted positions comprising a stationary surface, and a surface on said nut frictionally engageable with said stationary surface.

9. The combination according to'claim 7, said means for shifting said first wedge comprising a dual-acting piston and cylinder connected to said wedge at the end thereof opposite the end engageable with said screw.

10. The combination according to claim 7, said means for adjustably setting said initial feed adjusting sleeve comprising a worm Wheel secured to said sleeve, a manual adjusting shaft having a worm connected to said worm wheel, and an indicating dial connected to said shaft.

11. The combination according to claim 7, further pro vided with a plate rockably supporting said pawl for movement about the axis of said screw, a projection on said plate, said means for preselecting the pawl stroke comprising a manual fine feed adjusting shaft, a plurality of stop surfaces alternately shiftable by rotation of said shaft into obstructing relation with said projection, resilient means urging said pawl into engagement with said ratchet, and means responsive to movement of said pawl to a retracted position for withdrawing said pawl from said ratchet.

References Cited in the file of this patent UNITED STATES PATENTS Fraser June 5, 1934 Adcock July 8, 1941 Rickenmann May 3, 1949 Bialy Aug. 23, 1955 Bowen Oct. 22, 1957 Echegut Oct. 20, 1959 FOREIGN PATENTS Great Britain Aug. 2, 1961

Claims

1. IN A FEED MECHANISM, A SUPPORT MEANS GUIDING SAID SUPPORT FOR RECTILINEAR MOVEMENT, THREADABLY CONNECTED NUT AND SCREW MEMBERS, MEANS FOR ADJUSTABLY HOLDING ONE OF SAID MEMBERS IN A PREDETERMINED ANGULAR POSITION WITH RESPECT TO THE OTHER MEMBER, MEANS HOLDING SAID OTHER MEMBER AGAINST ROTATION DURING ADJUSTMENT OF THE ADJUSTABLE HOLDING MEANS FOR SAID ONE MEMBER, MEANS FOR SUCCESSIVELY ROTATING SAID OTHER MEMBER THROUGH A PLURALITY OF ANGULAR INCREMENTS WHILE SAID ONE MEMBER IS HELD BY SAID ADJUSTABLE HOLDING MEANS, MEANS HOLDING SAID OTHER MEMBER AGAINST AXIAL MOVEMENT, AND MEANS OPERATIVELY CONNECTING SAID SUPPORT TO SAID ONE MEMBER, WHEREBY SAID SUPPORT WILL BE MOVABLE IN RESPONSE TO AXIAL MOVEMENT OF SAID ONE MEMBER CAUSED BY ADJUSTMENT OF SAID ADJUST-