US 3156479 A
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Description (OCR text may contain errors)
Nov. 10, 1964 J. DRAZICK 3,155,479
LOCKING DEVICE Filed April 5, 1963 INVENTOR.
JON/V ORAZ/CK United States Patent M 3,156,479 LOCKING DEVICE John Drazick, 8565 Steel Ave., Detroit 28, Mich. Filed Apr. 5, 1963, Ser. No. 270,936 3 Claims. (Cl. 279-76) This invention relates to an improvement in a holding device and has particularly to do with toolholders utilizing a spring pressed detent to retain a tool in its socket.
These tools are used extensively for holding dies and punches in a die bed. It is important in these construction that it be easy to release these dies for replacement or for changing a particular set-up.
It is also important that the die be securely held against rotation in its particular socket and that it be solidly retained against removal from the stripping forces which are frequently present in the operation of a die of this kind. This invention contemplates an improvement over the structure disclosed in my US. Patent No. 2,969,243, dated January 24, 1961.
More specifically, in the previous disclosure, the holding device in the form of a plunger was so arranged that it had an actual point contact with the socket of the shaft being held. In View of the frequent application of the stripping forces and sometimes the tendency for these devices to rotate, it is desirable that there be more of an area contact between the plunger device and the wall of the recess in the shank of the tool.
In the present device, I have accomplished this by providing a detent device shaped to lie in contact over a considerable area of the holder recess in such a manner that forces transmitted to this area are absorbed through the detent to the body of the holding structure.
Other objects and features of the invention relating to details of construction and operation will be apparent in the following description and claims.
Drawings accompany the disclosure and the Various "iews thereof may be briefly described as:
FIGURE 1, a sectional view showing the general assembly of the device with the locking plunger and the body portion in section.
FIGURE 2, an enlarged view showing specifically the plunger and its relationship to the retaining body and the tool body.
FIGURES 3, 4, and 5, progressive sectional views on lines 33, 4-4 and 5-5 of FIGURE 2.
In FIGURE 1, the particular die bed, which is shown for purposes of illustration, comprises a hardened bottom plate It with a body plate 12, this body plate being screwed to the bottom plate and having a plurality of holes, one of which is shown at 14 designed to receive the shank 16 of a tool. Within the plates and 12 is an angled hole 13 which bottoms at 20, there being a compression coil spring 22 in this hole which presses outwardly against the detent or plunger 24. The plunger has a slot 26 defined by chordal walls 28 and 30 on the one hand and spaced parallel planes 31 parallel to the axis of the plunger on the other hand. The plunger is retained by a pin 32 which acts on the wall 30 and is retained in a hole 34 by a screw retainer 36 which has a hole 38, the margins of which retain the head of the pin 32.
The hole 38 permits access to the pin wherein a downward force will depress the plunger 24 out of the intersection with the tool 16. In the wall of the tool shank 16 is a recess 42 which is formed by a cylindrical end mill which is run into the wall of the shank 16 at about at 5 angle to the general angle of the plunger hole 18 (see FIGURE 1). This angle is preferably within the range of 3 to 10 and is preferably what is called a locking angle with respect to mutual wedging surfaces.
It will be noticed that the snub-nosed plunger 24 is provided with a clearance at 44 so that it does not contact the 3,155,479 Patented Nov. 10, 1964 2 walls of the recess 42. A portion of the side Wall of the plunger 24, however, opposite the slot 26, is shaped in a tapered surface illustrated in FIGURE 2 at 50. FIG- URES 3, 4 and 5 show this taper and the point of blending with the major circle of the plunger.
In FIGURE 3, the taper surface 50 blends at 52 to the major circle of the plunger and the tapered surface is formed circularly about an axis center 54. In FIGURE 4, the tapered surface 50 has blending points 56 a little closer to the center line and this surface is formed around a center 58. In FIGURE 5, the surface 50 has a blending point at 60 quite close to the center line and is formed around a center 62. This straight-walled partialcylinder surface is preferably formed at the 5 angle from the major axis of the plunger so that it will match with the surface of the recess 42 in the area indicated at 64.
Thus, as shown in FIGURE 2, between the section lines 3-3 and 5-5 and extending a little beyond on each side, the surface 50 is straight-walled tapered surface circular in cross section so that the plunger can actually have a wedging action against the wall of the recess 42.
The plunger is operated, of course, by inserting a punch member through the hole 38 to apply pressure to the head 4% of the pin 32, thus depressing the plunger against the spring 22.
When the shank of a punch or tool 16 is inserted into the hole 14, it will depress the plunger against the spring and then as the shank reaches its home position, the plunger will snap back through the action of the spring into contact With the wedge surface 64 of recess 42 over a wide area.
It will be seen that the so-called stripping forces, that is, forces which would tend to pull the shank 16 out of the hole 14, are transmitted to the plunger throughout the entire circumferential surface 50 which is axially in contact at 64 then up to the solid wall contact of the plunger with the recess 18 in the area indicated generally at 66. Thus, there is a solid cylindrical contact with the area 50-64 on the one hand and a solid cylindrical contact in the area 66 so that stripping forces are solidly met by a tight plunger with a wide wall surface contact on both sides. This is frequently very important where a punch is not circular.
While the device is disclosed in connection with the retention of a cylindrical shank 16, it will be appreciated that it could be utilized for the retention of other elements of different cross section as long as the recess in the element to be held is provided with the suitable mating surface.
1. A releasable holding device for retaining recessed elements in a retaining recess in which a releasable resiliently biased plunger engages a recess in the element to be retained and in which the plunger is inserted into an angled bore intersecting the retaining recess, that improvement which comprises a basically cylindrical plunger movable axially in a cylindrical bore, having one wall adapted to match complementally the cylindrical wall of the bore and having an opposite wall formed as a cylinder on an axis angled to the axis of said plunger and said bore, said angle increasing away from the bore and a complemental cylindrical angled wall in the recess of the element to be retained also disposed at an angle to the plunger angle similar to that of the opposite wall of said plunger wherein the two angled walls will wedge together as the plunger moves into the recess in the retained element providing a relatively large area of contact circumferentially and axially for transmitting dislodging forces through said plunger to the opposite wall of said bore.
2. In a releasable holding device for retaining recessed elements in a retaining recess in which a releasable resiliently biased plunger engages a locking recess in the element to be retained and in which the plunger is inserted into an angle bore intersecting the retaining recess, an improved tool shank to serve as the retained element, said tool shank having a shape to fit complementally into a retaining recess into which it is to be retained and having a locking recess formed in one wall thereof by the removal of stock, said locking recess having a cylindrical shape angled to the axis of the element to serve as a wedging surface for a retaining plunger wherein dislodging forces exerted on said element can be transmitted through said wedging surface.
3. A releasable holding device for retaining recessed elements in a retaining recess in which a releasable, resiliently-biased plunger engages a recess in the element to be retained and in which the plunger is inserted into an angled bore intersecting the retaining recess, that improvement which comprises:
(a) a basically cylindrical plunger movable axially in a cylindrical bore, having one wall adapted to 20 match complementally the cylindrical wall of the bore and having an opposite wall extending substantially approximately 180 around said plunger formed as a cylinder on an axis angled in the range of 3 to 10 to the axis of said plunger and said bore, said angle increasing away from the bore, and
(b) a complemental cylindrical angled wall in the recess of the elements to be retained also disposed at an angle to the plunger similar to that of the opposite wall of said plunger wherein the tWo angled Walls will Wedge together as the plunger moves into the recess in the retained element providing a large area of contact circumferentially and axially for transmitting dislodging forces through said plunger to the opposite wall of said bore.
References Cited by the Examiner UNITED STATES PATENTS 2,128,116 s/ss Boone 27976 2,138,253 11/38 Lynch 27976 2,969,243 1/61 Drazick 27976 FRANK SUSKO, Primary Examiner.
ROBERT C. RIORDON, Examiner.