US2863210A - Locking devices - Google Patents

Description

Dec. 9, 1958 c. b. TUCKER 2,363,210

LOCKING DEVICES Filed July 50, 1952 3 Sheets-Sheet 2 &

CHARLES D. TUCKER I B? ZZZ/fizz;

ATTORNEY INVENT'OR' Dec. 9, 1958 Filed July 50, 1952 FIG. I0. I

FIG.I2.

C. D. TUCKER LOCKING DEVICES- 3 Sheefs-Sheet 3 FIG.|5.

INVENTOR CHARLES D. TUCKER ATTORNEY United States Patent LOCKING DEVICES Charles D. Tucker, Cochranton, Pa.-, asslgnor to Mc- Crosky Tool CorporatiomMeadville, Pa., a corporation of Pennsylvania.

Application July 30, 1952, Serial No. 301,636 2 Claims. (Cl. 29-105) This invention relates to devices for locking or adjusting the blades or cutters of mills, boring bars, and the like, wherein the cuttingjor boringoperation is accomplished by a rotation of .the. tool body or holder. They are also applicable for thesame purpose in conjunction with toolsand stationary or non-rotating tool. holders, such as are found in lathes, shapers and inserted-bit broaches. While the invention will be specifically described in connection with the tool body of a mill its application thereto is not to be. construed as a limitation thereof for the reasons just given.

More particularly, the present invention is concerned with an effective but relatively inexpensive blade-locking unit to be substituted for those in the prior art. Basically, this new unit consists-of a metal body that is partially divided transversely intottwojparts which carry one or more screws operable to. distort the body to produce a locking action when the unit is in position beside a cutter blade.

In its general aspects the, invention contemplates the provision of one or'more, blade receptacles in a tool body or holder for the reception of one or more cutting blades or tools and a corresponding number of blade. locking devices, each constructed in the form of an assembly readily insertible and removable as a unit.

It is the primary object of the present inventionto devise a locking unit thatcan be distorted tov fulfill its purpose by changing its shape without appreciable change in its external size. In this connection, it is an object to form the unit body of a material that will spring back to its original shape when released from theforces creatingthe distortion.

Another major object of this invention resides in the provision of a clamping block that can be distorted to create three separate external points, lines or areas of outward force application; the purpose-of this being to obtain the full desired locking action automatically, and this in spite of errors in shaping the block and the walls of the tool body and blade against which it is designed to react. Thus, substantial machining tolerances are permissible.

It is a further object to design a slotted locking-member in such manner that the slot is concealed when in i use and hence closed against the entry of dirtand chips that might clog it and prevent or impede movement of the parts.

It also is an object to provide a locking unit body with a transverse slot that extends to a greatdepth from one side of the body towards the other and that is disposed approximately half way between the top and bottom of the body; all for the purpose of facilitating actuation of a locking screw and of assuring the three-zone contacts previously mentioned.

A still further object is to slot a clamping body so as to form a pair of integrally connected lever arms or leaves, and to provide one or the other of such arms with internal screw threads for association with a screw so that the arms are forced either towards each other or apart.

In any case, whether. the screw is placed undertension or compression, the body is distorted to createthreev external zones for application of clamping fOITCfiSr,

Continuing with the. foregoing generallobject, if a. headed screw is utilized the head mayhaye a universal;

seat, providedeither by machining, the bottom of the head spherically or by placing ajbeveled washer'orring against the, bottom of a: conventional screwhead.

It is a stillfurther object to' create resilience of thelocking body by appropriate; heat treatment-for -the material selected Tsothatxthe parts will spring, backxto initial.

shape after distortion; and, in this connection, to incorporate a snap ring orsplit washer sometimesinlhe assembled unit,- particularly where the unitahas a'large and heavy clamping; body, toaprovide anabutment against which the screw head may react to augment the inherentspring action of the distorted lever arms when they .are;

released: It should. be understood, however, that the washer may be utilized alone to aid in restoring;deadarms to initial shape or position.

Another; object is. to incorporate the'invention inan elongated, substantially rectangular bar designed; to be:

placed adjacent a cutting blade; this bar-shaped block being slottedlengthwise to format pair of leaves for association with a-plurality of spaced operating or clamp ingscrews.

The foregoing and further objects: of my invention should be readilyapparent. from a study of the;fol1owing description when taken in conjunction. with theaccompanying drawings, wherein:

Figure 1 shows,.in side elevation.andxlookingfintothe slot, one of theipreferred embodiments;olfi the lockingi;

unit of this invention;

Figure 2. represents; a section takenvertieally on the plane .ofline' 24-2, Figure 1.

Figure 3 illustrates, chiefly in section, the unit: of. Figures 1 and; 2 in association with. a blade ofgamillingy cutter, head, the screw having been. tightened,- to eifectv a; look. (In Figs. 3 and 4; possible rnachining errors:are inw the slot is cut into the round surface instead of the. flat side of the block.

Figures 7 and 8 correspond with Figures 5 and 6, the essential. difference being that, the screwis positioned eccentrically instead of coaxially with respectztothe curved surface of theblock.

Figure 9 illustrates, in vertical section, a unit (usually,

heavier than normal) in which a split ring, has been;

added.

Figures IOand ll show, in vertical section, twoways of providinga sphericalsurface at the bottom ofithelock-y ingscrew head of any. of the preceding forms ofthe invention.

Figure 12 is a section. illustrating a modification in;

which a headless screw is provided.for;the clamping action; and Figure 13, shows this sameembodiment after the screw has been placedunder compressiontoeffeet a lock.

Figure 14 is a planview of a further embodiment ofthe invention comprising an elongated and slotted bar in association with a blade of a milling cutter body.

Figure 15 is a sectional view taken on the planeoflline 1515, Figure 14.

to it a substantial resilience; and this block, which may vary in shape, has a transverse (approximately horizontal) Patented 1 Dec 9; 1958 3 slot 21 of substantially uniform width that divides it into a pair of lever arms or leaves 22, 23, bridged by an integral web or rib 24 that contains a cantilever fulcrum for a locking action presently described.

The arm 23 has an internally threaded hole .25 and the arm 22 has a plain hole 26 aligned with but larger than hole 25. The arm 22 has a counter-bored recess 27 aligned with both holes and of enough larger diameter to provide a horizontal annular shoulder 28.

Figure 4 shows that the block has a cylindrically curved wall 30 intersected by a vertical fiat face 31, the purpose of this shape being to fit the block freely into a correspondingly shaped recess 32 in a tool body 33 (sometimes rotary) that carries a cutting blade 34. Normally, the recess 32 is accurately formed, but it will be appreciated that it may have substantially errors in machining, this also being true of the block.

A screw comprising a round-cap and hex-recessed head 35 and a shank 36 has external threads 37 for reception in the hole 25. The head and shank have clearances in the recess 27 and the hole 26, respectively. The normal position of these parts is shown in Figures 1 and 2, with the head lightly engaging the shoulder 28. When the screw is tightened to place it under tension the free ends of the lever arms 22, 23 are drawn toward each other to narrow the slot 21 and distort the entire body 20; the fulcrum for this action being in the web 24 and creating three zones of force application A, B, and C. These zones are very important and, as seen in Figures 3 and 4, are theoretical points or lines but, probably, actually result in small deformed surface areas that produce exaggerated clearances 38 and 40 and also cock the screw head 35 to produce a clearance 41 (likewise exaggerated).

The action of the three zones A, B and C is triangular and automatic, thus under normal conditions causing the contact edges of the block 20 to bite into the matching surfaces of the recess 32 and the blade 34. The scheme is not just to latch the unit against radial outward movement, but to automatically adjust and lock itself with a tripod action into a socket that may have been created with appreciable machining tolerances. For example, although recess 32 is larger in Figures 3 and 4 at the bottom than at its top (as might occur in practice) the unit has locked itself securely at the three points A, B, C, and has done so without appreciable change in its body volume.

The cylindrically curved walls of the block 20 and the recess 32 permit the block to rockably adjust itself to ensure that the full width of its flat face contacts the blade in the locking zones B, C.

A further advantage resides in such arrangement of the slot 21 with respect to the other parts of the combination that its openings are fully concealed, except for small clearances; thus it cannot receive or accumulate chips and foreign material that might clog it and prevent free manipulation of the screw and the leverage arms.

In the foregoing treatment of the invention, the slot 21 was cut or otherwise formed into the flat side of the insertible body 20. It (the slot) may also be oppositely directed, coming into the rounded wall surface as shown in Figures 5 and 6. In either case and particularly that of Figures 5 and 6 because of the tightening screw possibly being too close to the fulcrum web 24 to give adequate leverage, the screw may be disposed off center as in Figures 7 and 8 (the offset depending upon which direction the slot is cut into the block 20) to increase the locking leverage exerted by the lever arms 22, 23.

Heat treatment of the metal is regarded as highly important in most cases, but in some instancesparticularly where a heavy unit is usedspring action alone may be inadequate to restore the lever arms to their initial positions when the device is to be unlocked. Accordingly, as in Figure 9, the counterbore 27 may have an annular groove 44 cut into it for reception of a snap ring 45. Thus, when the screw is retracted its head 35 engages the snap ring and forces the arms 22, 23 apart. This action, of course, can take place without any augmenting spring action in the event the block has little or no resilience.

Figure 10 illustrates an expedient for assisting the rocking action of the screw head, consisting in the provision of a spherical formation 46 at the bottom of the head for universal movement within a complementally shaped seat formed by the modified shoulder28a.

Instead, as in Figure 10, of utilizing a special screw, one with standard head will sufiice if a beveled washer 47 is provided to seat universally upon the shoulder 28a, this being shown in Figure 11.

The modified form of Figures 12 and 13 consists of a block 26a, slotted as heretofore described to provide a pair of normally parallel arms or leaves 22a and 23a. In this case the arm 23a is solid and the other arm bored and tapped to receive an unheaded locking screw 50. The latter bears against the top of arm 23a and, when tightened, forces the arms apart, the screw thus being under compression rather than tension. Here, because of this different action the zone A occurs at the open end of the slot, and rocking zones B and C are transferred to points or edges at opposite corners. The functioning of this unit is essentially the same as the other type. The slot may be cut into either the flat or round side surfaces of the block; and the screw may be either centered or eccentric.

Figures 14 and 15 illustrate how the invention lends itself for use in an elongated bar-type locking device. A tool body 52 carries a cutter 53. The recess or slot for the latter can be widened to form a full transverse socket 54 for reception of a rectangular block in the form of a bar 55. This bar is slotted at one side from end to end to form the slot 56 substantially midway between its top and bottom. A plurality of screws 57 are added and, when tightened (Fig. 15), create the important three zones A, B, C in the form of parallel lines of contact for locking purposes.

The embodiment of Figures 14 and 15 may be modified to add or to substitute some of the novel features noted in describing the preceding forms.

What is claimed is:

1. The combination with a cylindrical tool body having a recess extending inwardly from the periphery thereof and a blade mounted therein for adjustment radially of the tool body; of a blade locking device comprising a resilient metallic block fitted endwise into said recess between said blade and a wall of said recess, said block having a deep slot located between its ends in a plane transversely of said direction of adjustment to form a pair of spaced superposed integrally joined lever arms, and means carried by said arms and adapted to cause relative movement between said arms for moving the free ends of the arms in substantially arcuate paths extending in the general direction in which the blade is adjustable, whereby said block is expanded to cause at least one edge of the free end of each arm and an opposite portion of the block to wedge between said wall of said recess and said blade with substantially line contacts to lock the blade in the tool body, said line contacts extending in a direction normal to the direction of adjustment of the blade in the tool body.

2. The combination with-a tool body having a recess extending inwardly from a surface thereof, a blade mounted in said recess for adjustment in a direction outwardly of the surface of the tool body; and a blade lock.- ing device comprising a resilient metallic block fitted endwise in said recess between said blade and an opposed side of said recess and having a plane surface to engage said blade, said block having a deep slot located between its ends in a plane transversely of said direction of adjustment and through the plane surface thereof to form a pair of spaced superposed lever arms integrally joined by a web portion of the block, and a headed actuating screw having its shank extending freely through the upper arm and into threaded connection with the lower arm for moving the free ends of the arms toward each other in substantially arcuate paths extending in the general direction in which the blade is adjustable, whereby the edges of the arms remote from the slot are forced into substantially line contact with the blade and an external portion of the block adjacent the slot and at the side of the block opposite the free ends of the arms is forced into substantially line contact with the wall of the recess to lock the blade in the tool body, said line contacts extending in a direction normal to the direction of adjustment of the blade in the tool body.

References Cited in the file of this patent UNITED STATES PATENTS Wiles Jan. 4, 1876 Randall et a1 Feb. 12, 1878 McKay June 6, 1911 Vokal Aug. 11, 1925 Westgard Sept. 13, 1927 Miller Mar. 13, 1934 Jostich Oct. 12, 1943 Sheldrick Oct. 18, 1949 Skeel Apr. 3, 1951 FOREIGN PATENTS France Jan. 6, 1915

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