US 2795903 A
Description (OCR text may contain errors)
June 18, 1957 E A. s. TITCOMB CLAMP TO SECURE AN ABRASIVE SEGMENT ON A ROTARY CHUCK Filed 001:. '24, 1955 v INVENTOR- A. 5HEPARD 77TcoMa BY QQM fi' ATTORNEY United States Ettent 9 CLAMP T SECURE AW ABRASIVE SEGMENT ON A ROTARY CHUCK Albert Shepard Titcomb, Hamden, Conn.
Application October 24, 1955, Serial No. 542,216
6 Claims. (Cl. 51-209) This invention relates to an abrasive chucck, and more particularly to an abrasive segment holder which will adjustably secure the segment on a rotary plate.
In accordance with my prior Patent #2,54.l,844. of
February 13, 1951, I have provided a chuck in which a plurality of abrasive segments are supported in plowlike positions on a rotary plate so that the abrasive detritus may be moved outwardly and away from the zone of grinding as the segments are revolved. In that construction, an adjustable plate is provided which serves to hold the segment in one of several positions so that as the segment is worn away during usage it may be moved outwardly to provide more abrasive material for the grinding operation. The abrasive block is supported only by a corner engagement with a narrow ledge on an adjustable plate, and this support depends upon a screw threaded adjustment for properly positioning the plate to hold the segment.
The primary object of my invention is to provide a simpler and less expensive construction which will serve to hold an abrasive segment in one of two adjusted positions and which provides an extensive surface rigidly held in engagement with the segment in its outwardly adjusted position to prevent any accidental displacement thereof.
A further object is to provide a movable support which may be moved out of the way so that a segment may be mounted in the clamping holder in its initial position, or it may be moved outwardly to aposition where it supports a medial portion of the segment and is itself rigidly supported by the rotary plate. Further objects will be apparent in the following disclosure.
Referring to the drawings illustrating a preferred. embodiment of the invention:
Fig. 1 is a top plan view of a grinding chuck having three abrasive segments mounted therein in their secondary outwardly adjusted positions, the rotary supporting plate being indicated by dotted lines;
Fig. 2 is a perspective view of one of the individual abrasive holders showing particularly the inside of the holder and the adjustment plate in its abrasive supporting position;
Fig. 3 is an elevation of the outside of the holder and a portion of the mounting plate and 'a segment, shown bottom side up;
Fig. 4 is a top plan view of the abrasive block clamping unit with the adjustment plate shown by dotted lines in a secondary position; and
Fig. 5 is a fragmentary detail showing the lock for holding the abrasive supporting arm in position.
In the embodiment illustrated, the segment clamping unit comprises an arcuate metal body and an adjustable clamping jaw 11 which, as indicated in Fig. l, form a segment holder arranged to be mounted on a rotary plate 12, which is suitably mounted on a power driven spindle, usually arranged either horizontally or vertica-lly for rotating the abrasive segments in. an operative contact with the work piece supported thereagainst.
The body 10 has a fixed lip Iii-shaped to interfit with the trailing: end of the abrasive segment 14, and the adjustable. hook-shaped jaw 11 interfits with the leading end of the abrasive segment. The holder 10 is so mounted on the plate as to. impart the required revolving motion to; the segment, as. well as to support it for a plow-like action on the work, as explained in said patent. The inner arcuate face 1510f the segment holder unit is comprised of suitable land surfaces shaped to interfit with certain outer surfaces of the convex face of the abrasive segment, suitable pads being interposed between the abrasive segment and the metal walls of the holder to obviatje breakage, of the segment by the clamping pressure. The inner face of the segment is not supported except at the trailing end by the fixed lip and on the leading end by the adjustable jaw.
The, wedge-shaped leading; edge portion or plow-like nose of the abrasive segment is supported by and clamped inplace by. means of the adjustable jaw 11 which interfits therewith. This jaw is V shaped and comprises a rear portion 18 slidably interfitting in a socket 20 in the outer face of the clamp. body 10; That rear wall 18 of the adjustable jaw 11 is internally threaded lengthwise to receive a set screw 22 which passes freely through an outwardly projecting lug 23 (Fig. 1) "formed by 'a recess on the outside of the body- 10. The, enlarged head of the screw 22 has a recessed hexagonal socket or other suitable construction for receiving a wrench or screw driver which. serves to draw the nose plate 18 portion ofthe movable clamping jaw rearwardly to clamp the abrasive segment firmly in place in the holder. The adjustable jaw 11 does not extend the full height of the metal holder 10 but only about two thirds of the way.
Its lower edge portion lies in the plane of the bottom of the arcuate body 10 sothatit'will clamp fully against an. "abrasive block which has been moved outwardly to its. finally adjusted position. The body 10 is provided with suitable threaded holes 25 near its two ends whereby the block may besuitably seured to the rotary plate 12, as is described in my prior patent. Other constructional details shown in that patent may be incorporated in this device as it is modified to embody the present invention.
The primary feature of this invention resides in the movable plate or stop 30 which is so mounted that it may be moved from an inoperative position to one of extensively engaging the upper face of the abrasive segment and holding it in a lower adjusted position. This stop- 30. is preferably a swinging arm pivotally mounted on a vertical pivot pin 31 positioned in aligned holes 32; arranged in the upper and lower rib-like portions of the clamp body 33 (Fig. 2). formed by casting a central hole in the supporting clamp body 10. The arm 30 has an enlarged hinge lug 34 located in the central elongated hole between the ribs and provided with a pivot hole adapted to. carry the pivot pin. 31 for its swinging adjustment. The swinging arm 30,. in its inoperative positionrests. in-a recess 35 formed in the inside of the wall 10,
which has. such shape and dimensions that the arm 30:
will lie out of the way. of the convex outer face of the abrasive segment, or so that the concave inner wall of theswinging arm will be flush withthe inner arcuate face 15 of the body 10,. This permits the abrasive segment to be positioned initially in the. holder without interference from the swinging arm, It will be noted that the surface of the innerportion of the body 10 below the recess 35 forms. substantially 'a continuation of the arcuate surface 15 at the ends. of the body 10- and thus. provides. strength. in this lower area, the abrasive block being securely held in the end land portions. That is, a newa'brasi-ve block is mounted with its upper face substantially flush; with the top face of the holder and contacting with the under face of the rotary plate 12 and its lower operative portion projects out from the holder 19.
The swinging arm 30 is provided with outwardly projecting locating lugs 42 which project into larger holes 43 in the side of the holder 10. These lugs are flush with the lower edge of the swinging arm 30 and form wide under surfaces for engaging the abrasive block. The inside of the lip 13 is provided with a slight recess 45 so positioned that when the arm is swung outwardly to the position of Fig. 2, its free end locks releasably in that recess as permitted by a loose pivot and helps to hold the arm positioned. This locking movement may be readily aided by a tapered lock pin 44 removably inserted in aligned grooves in the body 10 and lug 34 which hold the end of the swinging arm rigidly in the recess 45. The pin is mounted in a hole 46 in the body 10 and its lower tapered end engages a wedging face 47 of a slot milled in the outside of lug 34'.
When new segments are mounted in the chuck, the arm 34) (Fig. 4) is located entirely out of the way. After the abrasive has worn down to substantially the lower face of the chuck, the clamping jaw 11, 18 is released from its clamping engagement with the forward nose of the segment, and the latter moved to a position which permits the arm 30 to be swung outwardly into the position shown in Fig. 2 and indicated in dotted outlines in Figs. 1 and 4. The segment is then positioned with its top face in contact with the lower edge portion of the arm, including the lugs 42, and the clamping jaw 11, 13 is then drawn into place to thrust the trailing portion of the segment into the V-shaped socket formed by the fixed lip 13. Since all of the arms 30 of the various segment holding blocks are similarly positioned, then the operative faces of the segments are automatically brought into the same plane, and when the clamping jaws are set, the chuck with its segments is then ready for renewed use. The drawing force of the jaw 11, 18 is required primarily adjacent that portion of the segment which is below the swinging arm 30. Hence, it is feasible to have the clamping jaw part 18 recessed into the end of the arcuate body 10 as shown at 20 in Fig. 1.
The arm 39 is supported only at its pivoted end, but its upper face lies in a plane and is adapted to contact fully with the under face of the rotary mounting plate 12 so that the upward thrust of the abrasive action against the segment is fully absorbed in that upper plate. These lugs have a further purpose, however, in that these lugs project through the holes in the side of the clamp body it), they automatically aid in freeing the holes from any accumulation of detritus formed by the disruption of the abrasive segment and removal of fragments from the work. Thus, lugs 42 have a primary purpose in that they are located at the extreme bottom edge and in line with its surface so that they form a wider supporting surface in engagement with the segment.
This construction differs from that of my prior patent in that it is much simpler in design and cheaper to manufacture and involves the loss of less time in the adjustment of the abrasive segment. In particular, the swinging arm 30 engages the segment throughout a considerable portion of its length and thus supports the segment medially between its leading plow point and trailing end which are clamped within the V-shaped sockets formed at either end of the clamp body by the movable jaw 11, 18 and the fixed lip 13, respectively. That is, the V sockets tend to hold the ends of the segment in place and the swinging arm supports the intermediate portion against the upward pressure of the grinding action. That is, the arm extends transversely across the median line between the two sides of the segments which is substantially the center of pressure and thus provides a balanced support for the segment.
The pivot support for the arm or abutment gate 30 is near the leading end of the segment holder, so that any swarf or residue which is swept into contact therewith tends to be thrown inwardly away from the segment and to a position where it may ultimately escape between the adjacent segment bodies when the rotary plate is rotated in the direction of the arrow in Fig. 1. In other words, this abutment gate 30 acts as a coolant guide. As explained in my prior patent, the forward nose of the segment is located radially inwardly of the trailing portion or end, and the segments are spaced apart and so arranged that the detritus will escape from the .inner side or edge of the segment that has ground it off of the stock and escape outwardly between two of the segment bodies being ploughed outwardly by the outer side of the succeeding segment, and thus be removed from the working zone. Hence, this gate 30 tends to sweep the residue away from the space above the segment within the clamp body.
Another advantage in this construction, as indicated particularly in Fig. 2, is that the arcuate body 10 has thick walled ends which are adequate for receiving large screws in the holes 25 so as to resist fully the centrifugal force of high speed revolution of the rotary plate 12. The body 19 is accordingly made thick at locations required for resisting the forces which would tend to cut off the screws interfitted in the holes 25. This is recognized as an improvement over our former construction, and is covered hereby.
In this grinding chuck the segment holders are open ended and so constructed that the abrasive segments may project close to or bear against the under side of the face 12 of the rotary plate during the initial grinding operation and thereafter may be supported by the movable arm 30 in an outwardly adjusted position. The arm 30 is so located that it engages the segment medially, in that it contacts with the segment between its forward and rear points or ends, and preferably it extends transversely across the segment somewhat near a central point so as to provide maximum lateral and longitudinal support adjacent the center of pressure. Also, this movably mounted segment support may be associated with various types of clamp made in accordance with standard constructions as well as that shown in my prior Patents No. 2,541,844 and No. 2,700,853. This movable arm may lie in a coextensive recess in the wall 10 and substantially in an inoperative position laterally of the segment, although the segment may or may not bear against and be partially supported by the inner curved face of the arm. In the construction shown, that inner face of the support 30 is nearly coextensive with the recess 35 and it forms substantially a continuation of the curved surface 15 of the holder. This can give a supplementary lateral support for the segment when first mounted. Although the swinging arm may be rigidly mounted on the body 10, it is desirable that its upper face or edge contact with the inside face of the rotary plate 12 so as to provide a rigid support for the segment.
The arm 30 is held in the outward position shown in Fig. 2 by means of the locking pin 44 which has a lower wedge shaped portion, as shown in Fig. 5, which engages the tapered face 47 of the slot milled in the outer circular portion of the lug 34 of the arm. In normal use the holder and abrasive are reversed from the position shown in Fig. 3 so that the pin is vertical and gravity tends to hold the wedge down in place. Various other modifications may be employed to lock this swinging arm in its outwardrnost position so as to provide an immovable rigid support for the top face of the abrasive segment.
Other modifications may be made in this construction, and the above description is to be construed as setting forth the principles of the invention and a preferred embodiment thereof and not as imposing limitations on the appended claims.
1, An abrasive segment holder comprising a hollow body having a side wall, a fixed V-shaped end hook for engaging one end of the segment and an adjustably mounted V-shaped hook for clamping the segment against the fixed hook with its outer abrading face projecting outwardly beyond the side wall, a movable segment support having an outer face capable of extending across the segment between its sides, and means for movably mounting the support on the holder body so that the support may move from a lateral non-supporting position to one where said outer face extends across and in contact with an extensive transverse portion of the inner face of the segment, said support having its segment engaging face remote from the plane of the outer edge of the side wall and between the hooks so that it may support the segment in an outwardly adjusted position while the segment is clamped between said hooks.
2. A grinding chuck comprising a rotary plate having an inner face, an abrasive segment holder secured against said face, said holder having a side wall and two opposed relatively adjustable hooks arranged for clamping the segment therebetween in one of two positions where its inner face is close to or alternatively is remote from said plate face, a segment support having an outer face shaped to engage an extensive portion of the segment transversely across its median line, and a pivot for the support mounted on the side wall, said support being movable from a position laterally of the segment to one where its inner edge engages said plate face and said outer face extends across and supports the segment in balance in a projected position.
3. A grinding chuck comprising a rotary plate having an inside face and a segment holder removably mounted on the plate, said holder having a recessed side wall and two opposed relatively adjustable members for clamping a segment therebetween, an arm pivoted on the holder and movable from a position within the recess laterally of the segment to one where it extends across the inner face of the segment and supports the latter in an outwardly adjusted position, said recess and arm being extensive so that the arm may extend fully across the segment, and the arm being shaped and arranged to contact at its opposite edges with the segment and said plate face so that the segment is rigidly supported against the grinding thrust.
4. A chuck according to claim 3 in which the holder side wall has openings therethrough and the pivoted arm has lugs projecting into the openings when located in the recess, the openings being larger than the lugs and aiding in removing the abrasive detritus.
5. A chuck according to claim 3 in which the segment holder and the arm have recesses that arealigned when the arm is in a segment supporting position and comprising a removable lock insertable in said aligned recesses to hold the arm rigidly in place.
6. A grinding chuck comprising a rotary plate having an inner face, an abrasive segment holder secured against said face, said holder having a side wall and two opposed relatively adjustable hooks arranged for clamping the noses of a segment therebetween in one of two positions where its inner face is close to or alternatively is remote from said plate face, a support having an outer face engageable with the segment inner face, and a pivot for said support mounted on the side wall near the forward nose of the segment, said support being movable from a non-supporting position laterally of the segment to one where its inner edge engages the rotary plate and said outer face extends obliquely and rearwardly towards the trailing end portion across and in supporting contact with the segment, so as to aid in keeping the inner surfaces of the holder free of detritus during the grinding operation.
References Cited in the file of this patent UNITED STATES PATENTS 2,541,844 Titcomb Feb. 13, 1951