US3086229A - Interconnected pivoted latch means for die-heads - Google Patents

Description

April 23, 1963 R. M. STRICKLAND 3,

INTERCONNECTED PIVOTED LATCH MEANS FOR DIE-HEADS Filed Sept. 12, 1961 2 Sheets-Sheet 1 44 4 IO 46 30) 28 2. i 15 2 4 2 50 90 '9 1' 1 f as I2 INVENTOR Royce M. STR/C/(L AND A11: Arron/a vs.

April 3, 1963 R. M. STRICKLAND INTERCONNECTED PIVOTED LATCH MEANS FOR DIEHEADS Filed Sept. 12, 1961 2 Sheets-Sheet 2 INVENTOR RovcE M- S'TR/c kuwo 51's Arrozzwzys United States 'Patent 3,086,229 INTERCONNECTED PIVOTED LATCH MEAN FOR DIE-HEADS Royce M. Strickland, New Haven, Conn, assignor to United-Greenfield Corporation, Chicago, 111., a corporation of Delaware Filed Sept. 12, 1961, Ser. No. 137,693 7 Claims. (Cl. -95) The present invention relates to thread-cutting die-he ads, and it relates more particularly to latch means for locking the thread cutting elements or chasers in a predetermined position.

It is common practice to provide die-heads with means for latching the chaser operating or closing member in a working position where the chasers are to be fixed for cutting the desired threads in a work-piece. Latch means may also be used to limit the movement of the operating member beyond the so-called chaser-retracted position on certain types of die-heads where the chasers are positioned out of engagement with the work and, in other types of die-heads, in the chaser-clearance position where the operating member is clear of the chasers so that they can be removed and replaced. Upon the release of the chaser-operating member by disengagement of such latch means, the 'chasers, which are spring-loaded away from their working position will retract outwardly from one position to the next. An example of a die-head of the self-opening type in which such latch means are employed isshown in the patent to Breitenstein, 1,639,719. In the Breitenstein construction, as in most self-opening dieheads two separate latch means are provided, one for latching the operating member in working position and theother for latching it in the chaser-retracted position. Upon release of the operating member from its chaserretracted position, it move to its chaser-clearance position. However, in the so-called solid or non-self-opening type of die-head, the chaser-operating member usually has only two positions, a working position and a chaserclearance position. In addition, in most die-heads, whether of the self-opening or solid type, the chasers may be adjusted for cutting threads of precise diameters.

In die-heads of either the self-opening or solid type with which the present invention is concerned, the chaseroperating member. consists of a closing sleeve supported by a frame or skeleton for longitudinal movement thereon. The chasers are mounted in radial tracks at the front end of the skeleton and are engaged at their outer ends by a closing sleeve which, when moved forwardly, forces the chasers inwardly to their working positions and, when moved :rearwardly, permits them to move outwardly to their retracted positions. When the closing sleeve is moved sufiiciently far to the rear, it clears the outer ends of the chasers so that they can be removed from their tracks and replaced when in need of sharpening or when a different thread is required. p The primary object of the present invention is to provide an improved stop-means for latching the operating member in any one of the positions mentioned above depending on the particular type of die-head involved. Another object of the invention is to provide stop-means for the operating member which prevent it from being cocked out of line with the adjacent parts or from binding so that it does not move freely.

In general the invention resides in improved stop-means for the operating member comprising two or more stoplevers, desirably equally spaced about the longitudinal axis of the skeleton, each stop-lever being pivoted intermediate its ends for movement into and out of latching position with respect to the operating member. The ends of the stop-levers are interconnected so that if one is moved out of latching position, all are pivoted out of latching position simultaneously. Resilient means, such as springs, urge the stop-levers into latching position.

In order that a clearer understanding of the invention may be obtained, one practical embodiment thereof is described hereinafter with reference to the accompanying drawings showing application of the invention in a diehead of the solid or non-self-opening type.

In the drawings,

FIG. 1 is a central longitudinal vertical section through a typical die-head in which the invention may be employed;

FIG. 2 is a section taken on the line 22 of FIG. 1, but showing the adjusting ring rotated 45 in a clockwise direction from its position in FIG. 1;

FIG. 3 is a section taken on the line 3-3 of FIG. 1, but showing the adjusting ring in the position shown in FIG. 2;

FIG. 4 is a view similar to FIG. 3, but showing the stop-levers depressed out of latching position;

FIG. 5 is a front end View partially broken away of the die-head shown in FIG. 1;

FIG. 6 is a detail sectional view taken on the line 66 of FIG. 5; and

FIG. 7 is a perspective View of the adjusting ring only.

The particular die-head illustrated by way of example in the drawings includes a main frame or skeleton, socalled, having a cylindrical head-portion 1t and a central shank 12 extending rearwardly therefrom. The forward face of head-portion 10 is formed in this instance with four radial slots 14 (FIGS. 5 and 6), in each of which is guided a chaser holder 16. Holders 16 carry individual thread-cutting dies or chasers 18 for threading a workpiece (not shown). The chaser assembly of the present construction is similar to that shown in the patent to Breitenstein, 1,756,277, and need not, therefore,.be described in detail here. It will be understood, of course, that other types of chasers may be employed if desired. For example, the chasers may be mounted directly in slots 14 instead of on holders 16. p

In the construction here illustrated, chaser holders 16 are retained in slots 14 by means of segmental plates 19, which are rigidly secured to the forward face of the skeleton by screws 29. Each chaser holder 16 is urged outwardly toward its retracted position by a spring plunger assembly 22 (FIG. 6). In addition, each holder 16 is formed at its outer end with a sloping cam-surface 24, which is engaged by asimilarly sloped cam-surface 26 formed on the inner forward corner of a cup-shaped, chaser-operating sleeve 28. Sleeve 28 is mounted on the skeleton for axial sliding movement thereon and bears along the inner sides of its forwardly extending walls 30 on the periphery of head-portion it) of the skeleton. Sleeve 28 is provided at its rear end with an inwardly disposed annular flange 32, the inner edge of which bears against the periphery of a cylindrical adjusting ring 34 threadedly mounted on shank 12 of the skeleton. It will be seen that axial movement of sleeve 28 forwardly cams chasers 18 into working position, while rearward movement thereof permits the chasers to retract outwardly. A key 36 (FIG. 5), fitting a keyway 38 in the inner surface of wall 30 of sleeve 28, prevents rotation of sleeve 28 with respect to head-portion 10 of the skeleton.

In passing, it should be noted that in the particular die-head construction here shown, the walls 30 of operating sleeve 28.,are relatively narrow longitudinally of the skeleton. While certain advantages are attained by employing such a narrow operating sleeve, there is a tendency, nevertheless, due to the construction for the sleeve to tilt more easily when moved axially and therefore to bind or become jammed while the chasers are being moved int-o the desired working or operating position.

It is important therefore in moving the operating sleeve 28 forward to exert pressure symmetrically, i.e. on both sides, of the rear face of the sleeve in order to prevent it from binding. As will be brought out hereinafter, the present invention makes it practical to do this.

Operating sleeve 28 is urged in a rearward direction by a pair of spring plungers 46 carried by the cylindrical head-portion 10 of the skeleton and disposed on diametrically opposite sides thereof. Plungers 4d are guided within bores 42 drilled in head-portion 19 parallel to the longitudinal axis of shank 12. Each plunger 46 is provided with a socket 44, within which is received one end of a coil spring 46 which urges the plunger rearwardly against flange 32 of operating sleeve 28. The forward end of each spring 46 rests against the inner side of one of the segmental plates 19 at the front face of the diehead. It will be noted that each plunger is formed with a clearance cut 48 at its rear or sleeve-engaging end in order to avoid engagement with adjusting ring 34 and to permit adequate rearward movement of plungers 40 when operating sleeve 28 is released from the working position in which it is shown in FIG. 1.

The latch-means for the operating sleeve, to which the present invention is particularly directed, includes a pair of arcuately shaped stop- levers 50, 52, each pivoted near its mid-point within similarly shaped slots 54 and 56, respectively, in adjusting ring 34-. As best seen in FIG. 7 slots 54 and 56 are formed on opposite sides of adjusting ring 34 in a plane perpendicular to the longitudinal axis thereof. Pivot pins 58 for the stop- levers 59, 52 are located diametrically opposite each other such that they pass through the central portions of slots 54 and 56 and are held firmly at their ends in passages 59 drilled longitudinally in adjusting ring 34, into which they are press fit. Slots 54 and 56 are cut transversely through adjusting ring 34 to a suitable depth in order to leave oppositely disposed connecting portions 60, 62 in the annular wall of adjusting ring 34. The ends of arcuate slots 54, 56 are defined by parallel chords disposed perpendicular to a diameter of the adjusting ring through pivot pins 58.

As best seen in FIG. 4, the outside diameter of stoplevers 50, 52 is approximately equal to the CD. of adjusting ring 34 so that they can be pivoted to a position wholly within the periphery of the adjusting ring. In order to provide room within slots 54, 56 for stop- levers 50, 52 to move between their latching positions shown in FIG. 3 and unlatching positions shown in FIG. 4, one end 52' of each stop-lever is made slightly shorter than the other. In the latching position of FIG. 3, a wedge-shaped segment on each of the opposite ends 50", 52 of stop-levers 5t 52 projects outwardly of the peripheral surface of adjusting ring 34 so that, as shown in FIG. 1, they engage the rear side of flange 32 of the operating sleeve 28, holding this member in its forward or chaser-closing position. When stop-levers 5t), 52 are pivoted clockwise, as viewed in FIGS. 2-4, to the unlatching position of FIG. 4, the ends 56'', 52" are retracted within the periphery of adjusting ring 34 permitting operating sleeve 28 to slide rearwardly to its chaseropening position. An outwardly directed flange 63 at the rear end of adjusting ring 34 limits the rearward travel of operating sleeve 28 at a position in which the walls 30 thereof clear the chaser holders 16 so that they may be removed from the radial guide slots 14 for replacement.

The adjacent ends 56' and 52" as a pair, as well as ends 50" and 52 as a second pair, of stop- levers 50 and 52 are interconnected by means of identical plungers 64 and 66, which are guided within passages 68 and 70, respectively, through the connecting portions and 62 of adjusting ring 34. Plungers 64, 66 are in substantially continuous engagement with the opposite ends of stoplevers 5t), 52 so that any pivotal movement of one causes a corresponding movement of the other. Plungers 64,

i 66 are each provided with an enlarged cylindrical headportion 72 and 74, respectively, forming annular shoulders 76, 73 adjacent the smaller diameter shanks 81 on which are fitted helical compression springs 82, 84. The opposite ends of each of passages 68, 70 is reduced in diameter in order to accommodate and guide the shanks 80, 81 of plungers 64, 66 and also to form an internal shoulder within each of passages 68 and 70 against which one end of each compression spring 82, 84 is seated. The opposite end of each compression spring engages one of the shoulders 76 or 78 on each plunger.

As shown in FIGS. 3 and 4, the plungers 64 and 66 are arranged so as to urge stop- levers 50 and 52 in a counterclockwise direction toward their latching positions. It will be noted, however, that by pressing inwardly either on the end 5!)" of stop-lever 50 or on the end 52" of stop-lever 52, both stop-levers will be pivoted simultaneously from their latching positions to their unlatching positions. Since in the present construction the die-head is designed to have the chasers opened manually, finger- cuts 86, 88 are formed in the rear part of the adjusting ring 34- adjacent the latching portions of the stoplevers at their ends 50", 52". The finger- cuts 86, 88 provide better access to the stop-levers so that one or the other, or both, can be more readily depressed by hand. In order to allow the operating sleeve 28 to be moved from its chaser-opening position, at which point its flange 32 is adjacent flange 63 on adjusting ring 34, it is necessary to depress stop- levers 50, 52 which, of course, snap outwardly when flange 32 passes to the rear of adjusting ring 34'. To this end, the outer rear edge of each of the wedge-shaped latching portions of stop- levers 50 and 52 is bevelled as shown at 90 and 92, respectively, in FIG. 1. In addition, the forward corner of flange 32 is also bevelled so that as sleeve 28 is slid forward it will engage the bevelled surfaces of stop- levers 50, 52 and will depress them until the flange 32 passes in front of them.

Adjusting ring 34 is provided in the usual manner with a tool socket 94 to receive a suitable tool for turning it on shank 12 in adjusting the chasers to the desired thread size. A set-screw 96 is also provided for locking the adjusting ring in place once the desired adjustment has been made.

Since the stop-levers in the present construction engage the operating sleeve at diametrically opposite points, the operating sleeve is not tilted or cocked as it is being adjusted longitudinally of shank 12 by means of adjusting ring 34. In order to ensure this, however, it is of course important that the two stop- lever slots 54 and 56 in the adjusting ring be accurately in line. While the same advantage could be obtained by using independently movable stop-levers located on opposite sides of the adjusting ring, this is not satisfactory because it is diflicult to depress both levers simultaneously in order to release the operating sleeve. The present invention, however, has solved this problem well and renders the use of two, or even more, stop-levers practical.

What is claimed is:

1. In a die-head comprising a skeleton or frame having an elongated shank, a plurality of chasers mounted on said skeleton for reciprocal movement radially of the longitudinal axis of said shank into and out of workengaging position, an operating member supported on said skeleton for movement longitudinally of said shank in one direction in order "to move said chasers into workengaging position and in the other direction for retracting said chasers, and stop-means positioned on said shank for limiting the movement of said operating member in said other direction; the improvement in which said stopmeans comprises in combination a plurality of stop-levers each pivoted intermediate its extremities for movement into and out of latching position with respect to said operating member, means interconnecting adjacent ends of said stop-levers such that each of said stop-levers is pivoted out of latching position upon pivotal movement of any one of said stop-levers out of latching position, i

and resilient means urging said stop-levers into latching position.

2. The combination defined in claim 1, wherein said stop-means comprises a pair of said stop-levers disposed diametrically opposite each other on either side of said shank, the pivotal movement of said stop-levers being in a plane normal to the longitudinal axis of said shank.

3. In a die-head comprising a skeleton or frame having an elongated shankpa plurality of chasers mounted on said skeleton for reciprocal movement radially of the longitudinal axis of said shank into and out of workengaging position, an operating member supported on said skeleton for movement longitudinally of said shank in one direction in order to move said chasers into workengaging position and in the other direction for retracting said chasers, and stop-means positioned on said shank for limiting the movement of said operating member in said other direction; the improvement in which said stopmeans comprises in combination a pair of stop-levers disposed opposite each other on either side of said shank, each stop-lever being pivoted intermediate its extremities for movement into and out of latching position with respect to said operating member, a pair of plungers interconnecting adjacent ends of said stop-levers such that each of said stop-levers is pivoted out of latching position upon pivotal movement or any one of said stop-levers out of latching position, and resilient means urging said stop-levers into latching position.

4. In a die-head comprising a skeleton or frame having an elongated shank, a plurality of chasers mounted on said skeleton for reciprocal movement radially of the longitudinal axis of said shank into and out of workengaging position, an operating member supported on said skeleton for movement longitudinally of said shank in one direction in order to move said chasers into workengaging position and in the other direction for retracting said chasers, and stop-means positioned on said shan for limiting the movement of said operating member in said other direction; the improvement in which said stopmeans comprises in combination a pair of stop levers disposed opposite each other on either side of said shank, each stop-lever being pivoted intermediate its extremities for movement into and out of latching position with respect to said operating member, means interconnecting adjacent ends of said stop-levers comprising a first springloaded plunger having one end urging a first of said stoplevers in one direction about its pivot point and the other end disposed for engagement with the second of said stop-levers, a second spring-loaded plunger disposed between the opposite ends of said stop-levers and urging said second stop-lever into engagement with said first plunger.

5. The combination defined in claim 4, wherein said stop-levers are identical and said spring-loaded plungers are likewise identical.

6. The combination defined in claim 4, wherein each of said spring-loaded plungers includes a compression spring urging one end of the plunger associated therewith against one of said stop-levers, the other end of each of said plungers extending in the opposite direction into engagement with the other stop-lever.

7. The combination defined in claim 4, wherein said stop-means is disposed in and supported by an adjusting ring threaded on the shank of said skeleton tor adjustably positioning said stop-levers longitudinally ofsaid shank.

References Cited in the file of this patent UNITED STATES PATENTS 1,683,126 .Breitens-tein Sept. 4, 1928 1,753,819 Breitenstein Apr. 8, 1930 2,958,877 Strickland Nov. 8, 1960

Claims (1)

1. IN A DIE-HEAD COMPRISING A SKELETON OR FRAME HAVING AN ELONGATED SHANK, A PLURALITY OF CHASERS MOUNTED ON SAID SKELETON FOR RECIPROCAL MOVEMENT RADIALLY OF THE LONGITUDINAL AXIS OF SAID SHANK INTO AND OUT OF WORKENGAGING POSITION, AN OPERATING MEMBER SUPPORTED ON SAID SKELETON FOR MOVEMENT LONGITUDINALLY OF SAID SHANK IN ONE DIRECTION IN ORDER TO MOVE SAID CHASERS INTO WORKENGAGING POSITION AND IN THE OTHER DIRECTION FOR RETRACTING SAID CHASERS, AND STOP-MEANS POSITIONED ON SAID SHANK FOR LIMITING THE MOVEMENT OF SAID OPERATING MEMBER IN SAID OTHER DIRECTION; THE IMPROVEMENT IN WHICH SAID STOPMEANS COMPRISES IN COMBINATION A PLURALITY OF STOP-LEVERS EACH PIVOTED INTERMEDIATE ITS EXTREMITIES FOR MOVEMENT INTO AND OUT OF LATCHING POSITION WITH RESPECT TO SAID OPERATING MEMBER, MEANS INTERCONNECTING ADJACENT ENDS OF SAID STOP-LEVERS SUCH THAT EACH OF SAID STOP-LEVERS IS PIVOTED OUT OF LATCHING POSITION UPON PIVOTAL MOVEMENT OF ANY ONE OF SAID STOP-LEVERS OUT OF LATCHING POSITION, AND RESILIENT MEANS URGING SAID STOP-LEVERS INTO LATCHING POSITION.

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