US2389590A - Thread grinding machine - Google Patents

Description

N 7, 1945- G BRINKMANN 2,389,590

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G. BRINKMANN THREAD GRIND ING MACHINE Filed March 18, 1942 18 Sheets-Sheet l6 am firw'mfhrzmm E MC' F *W mag-7s Patented Nov. 27, 1945 ,rnnmn GRINDING monmn Guenther Brinkmann,

Detroit, Mich., assignor to Ex-Cell-O Corporation, Detroit, Mich., a corporation of Michigan Application March 18, 1942, Serial No. 435,224

14 Claims.

The present invention relates to improvements'in thread grinding machines, and has reference'particularly to machines adapted for the grinding of internal threads.

One of the objects of the present invention is to provide a novel thread grinding machine having a longitudinall reciprocable work head, a transversely reciprocable grinding wheel head movable selectivel in one direction into operative position or in the other direction into idle position, a dressing mechanism for dressing the grinding wheel in the idle position, and means for imparting a dresser feed to said wheel head and simultaneously adjusting the efiective operative position of the wheel to compensate for the dresser feed.

Another object is to provide a, new and improved internal thread grinding machine of the foregoing character having an automatic cycle in which the grinding wheel will be dressed selectively either after a predetermined number of grinding passes, or after the completion of a single workpiece, or after the completion of a predetermined number of workpieces.

A further object is to provide a. novel thread grinding machine of the foregoing character having cross feed mechanism for imparting an incremental cross feed to the grinding wheel at the end of each grinding pass, and including means selectively available for automatically retracting the grinding wheel from the work during the passes in one direction or the other of the work head reciprocation.

Other objects and advantages will become apparent as the description proceeds.

Referring to the drawings,

Figure 1 is a, front perspective view of a machine embodying the features of the invention.

Fig. 2 is a rear perspective view.

Fig. 3 is a left-end elevational view, partially in section along line 3-3 of Fig. 1, and illustrating the work head.

Fig. 4 is a detail sectional view taken along line 4-4 of Fig. 3, and illustrating the speed-change mechanism in the drive for rotating and translating the work.

Fig. 5 is a longitudinal vertical sectional view of the work head, taken substantially along line 5-5 of Fig. 3. V I

Fig. 6 is a transverse vertical sectional view of the work head, taken substantially along line 6-6 of Fig. 5.

. Fig. 7 is a fragmentary detail view taken along line 1-1 of Fig. 6, and illustrating a gear-change mechanism in the rotary work spindle drive.

Fig. 8 is a fragmentary transverse vertical sectional view taken substantially along line 8-8 of Fig. 5, and illustrating means 101' eifecting lead pick-up and backlash compensation.

' Fig. 9 is a fragmentary front elevational view illustrating cycle control does and switches operable by the work head.

Fig. 10 is a fragmentary vertical sectional view taken substantially along line ill-l0 01 Fig. 1 through the grinding wheel slide.

Fig. 10;: is a detail sectional view of a switch operating mechanism controlled by the wheel slide.

Fig. 11 is a fragmentary vertical sectional view taken along line I l-I l of Fig. 10, and illustrating the actuating means for the cross-feed mechanism.

Fig. 12 is a fragmentary vertical sectional view taken along line I2-l2 of Fig. 13, and illustrating a pawl and ratchet drive in the cross-feed mechanism.

Fig. 13 is a vertical sectional view taken substantially along line vl3-l3 of Fig. 12, and illustrating the cross-feed mechanism for the grinding wheel slide. v

Fig. 14 is a vertical sectional view taken along line H-ll of Fig. 10, and illustrating a dressing feed mechanism for the wheel slide.

Fig. 15 is a fragmentary plan view taken in the direction of the arrows l5-l5 of Fig. 14, and illustrating a gearing in the dressing feed mechanism.

Fig. 16 is a vertical sectional view taken along line IG-IB of Fig. 13, and illustrating the actuator 01' a wheel retract mechanism associated with Q the cross-feed mechanism.

Fig. 17 is a detail sectional view of the crossfeed mechanism taken along line ll-ll of Fig. 13.

Fig. 18 is a perspective view of certain elements of the retract mechanism shown in exploded relationship.

Fig. 19 is a fragmentary perspective view of the machine, and particularly illustrating the wheel dressing mechanism and the dressing feed mechanism.

Fig. 20 is a general diagrammatic representation of the various drives in the machine.

Fig. 21 is a plan development of index graduations associated with the work spindle.

Fig. 22 is a sectional view taken along line 22-22 of Fig. 14, afid illustrating the actuating means for the dressing feed mechanism.

Figs. 23, 24 and 25 are schematic diagrams While the invention is susceptible of various modifications and alternative constructions, I

have shown in the drawings and will herein describe in detail the preferred embodiment, but

it is to be understood that I do not thereby in-' tend to limit the invention to the specific form disclosed, but intend-to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawings, the machine constituting the exemplary embodisionl 'attherearofthegrindingwheelGisa suitable dressing mechanism II for truing the grinding wheel G when the tool head I is shifted into offset idle position. A dresser feed mech-, anism I2 is automatically operable to adjust the idle position of the tool head I incrementally to ward the dressing tools for each dressing operation, and simultaneously to adjust the operative position of the tool head relatively to the workpiece W independently of the cross feed mechanism I to compensate for the reduction in diameter of the grinding wheel G in the dressing operation.

The operation of the machine is controlled by an electrical system in which the movements of th main units are interlocked and timed, and

which is selectively adjustable to obtain any one of a substantial number of automatic machine merit of the invention is of the type adapted for grinding internal screw threads, and comprises an elongated horizontally disposed base i formed on the top with a longitudinalset of ways 2 for supporting a work head I, and having a rearward extension I formed with a set of transverse ways I for supporting a tool head I. A rotary ltool spindle 1 is mounted in the tool head I and supports a suitable grinding wheel G. A work spindle 8 is mountedin the work head I, and is adapted to rotate and translate a workpiece W axially through cutting engagement with the grinding wheel G in timed relation to the rotation as determined by the lead of the thread or threads to be ground The tool head I is shiftable transversely of the work spindle I to locate the grinding wheel G either in operative position at the forward limit of travel or in idle or dressing position at the rearward limit of travel. when the grinding wheel G is located in the operative position, it is substantially alined with the work spindle I to enter and take a grinding pass or series of passes through the workpiece W. Relative working translation between the grinding wheel G and the workpiece W is obtained by reciprocating the work spindle I through a selected program of movements, such for example as a rapid approach to grinding position, a slow iorward feed through the working range, and a rapid return to idle position. v

The spindle I may be rotated in either direction relative to the translation in accordance-with the hand of the thread to be ground. At each reversal of translation, the rotation of thespindie I is reversed, and the spindle is'shifted axially to'compensate for backlash in the drive:. The work spindle I also is shiftable axially for lead pickup, and is adapted to be indexed when grinding multiple threads to locate the threads successively in correct cutting relation to the grind.

ing wheel G.

A cross feed mechanism I is provided for automatically adjusting the operative position of the wheel G step-by-step in timed relation to the successive working passes of the spindle I until the workpiece W has been ground to ilnal size. A retract mechanism III is automatically operable to separate the grinding wheel G laterally from the workpiece W during all rapid traverse movements without aifecting the setting oi the cross feed mechanism.

Mounted in a fixed position on the base extenwithinthe capacity of the counting mechanism.

The work head The work head I comprises a longitudinal subbase or slide II which is mounted on the ways 2 or the machine 'base I for manual adjustment longitudinally of the work spindle I, and which. during the normal machine operation, is clamped in position of adjustment.

To provide means for eifecting the manual ad- ,iustment, the outer end of the base slide 20 is formed between the ways 2 with a longitudinal bore 2| having a counterbore 22. A stationary nut II is fitted in the'counterbore II, and has an outer .end flange II bolted to the slide II. An adjusting screw, II extends through threaded engagement with the nut II into the bore 2|. The outer end of the screw II is rotatably anchored against endwise movement in an end wall II on the machine base I, and has a squared end I1 for engagement by a suitable hand tool (not shown).

The base .slide- II is adapted to be secured adjacent its ends to the base i by two similar manually operable clamping devices. Each clamping device comprises transverse clamping bar II slidably engaging at opposite endsin two longitudinal grooves II formed in the inner sides of the ways 2. A clamping plunger II extends upwardly through an opening in an intermediate portion of the clamping bar II and has a head II engaging the underside thereof. The upper end or the plunger II extends slldably into a vertical bore II in the base slide II, and is formed in one side with a conical recess II. A clamp screw II is adjustablythreaded through the base slide II into the bore I2, and has a conical pin II on the inner end adapted for wedge engagement with the upper side of the recess II. The screw II is provided with a squared end II adapted to be engaged by a suitable hand tool (not shown). It will be seen that when the screw II is turned inwardly, the plunger II will be forced upwardly to clamp the bar II securely against the upper sides of the grooves II 'in any position of adjust

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