US 2796788 A
Description (OCR text may contain errors)
June 25, 1957 D. BOHN v 2,796,788
MAGNETICALLY LOCKABLE UNIVERSAL VISE SUPPORT Filed June 29, 1954 2 Sheets-Sheet 1 /UHH/HH/H/,HHIMIl, MAM M June 25, 1957 D, 1, BOHN 2,796,788
MAGNETICALLY LOCKABLE UNIVERSAL VISE SUPPORT Filed June 29, 1954 2 Sheets-Sheet 2 QECT/ F/Ee) BY mym United States MAGNETICALLY LCKABLE UNIVERSAL VISE SUPPORT My invention relates to a new and improved work-holding device and more particularly to a new and improved universal vise for holding workpieces in accurate, predetermined positions.
In clamping a workpiece rigidly, it is often necessary to accurately position the workpiece in a predetermined position in order to permit accurate work thereon, such as threading and the like.
In using a vise, it has always been a problem to provide a device which would be capable of holding the workpieces in various vertical, horizontal, and angular positions and which would, at the same time, allow the workpiece to be held rigidly in the desired position. Heretofore, it has been the practice to lock the device in position with clamping screws or other mechanical means. However, these methods have not always proven adequate in situations where the operator desires to hold the workpiece in place by tightening the clamp, which holds the workpiece, with a sharp and sudden motion. This motion, in a universal device, will cause some slippage between the ball and socket upon which the work holder is mounted, thereby jarring the vise out of the desired position.
In essence, my invention contemplates a universal vise support which is locked in the desired predetermined posi* tion, not by a mechanical movement, but by electromagnetic action.
Accordingly, it is an object of my invention to provide a universal vise support wherein the work holder may be clamped rigidly into various predetermined positions which will be maintained despite any final tightening movement by the operator.
Another object of my invention is to provide an electrical means for locking a universal vise support into position.
Another object vis to provide a novel universal vise support with a locking means which permits the vise either to be locked rigidly or to be rotated freely at the will of the operator.
A further object is to employ magnetic action which is easily controllable to rigidly lock the components of a universal vise support in any desired position.
A still further object is to provide a universal vise support in which a vise-supporting hemisphere may be held firmly in a cradle, whether the cradle be placed in a horizontal, vertical, or angular position.
These and other objects will be clearly understood by one skilled in the art from the following description taken in connection with the accompanying drawings.
My invention involves a universal vise wherein the work holder is mounted on a hemisphere which rests in a socket or cradle having the configuration of segmental portions of a sphere, half-round saddles, or any other shape which allows the hemisphere to freely assume various positions, the hemisphere being locked in any selected position by magnetic action. The cradle for my vise is provided with an electro-magnet, the flux lines arent 'ine from which are directed toward the surface where the cradle contacts the hemisphere. The magnet may be energized or deenergized at the will of the operator. Thus the hemisphere can rotate freely and assume :any position in the cradle until such time as it is desired to rigidly lix its position therein, whereupon it may be magnetically locked in the desired position by closing the circuit which energizes the electro-magnet. When it is desired to remove the work holder or to change its position, the circuit is open, and the hemisphere can again be rotated freely.
This is fully illustrated in my drawings in which:
Figure l is atop plan view of my vise and its universal support.
Figure 2 is a vertical cross section of the vise taken along the line 2-2 of Figure 3.
Figure 3 is a right-hand elevation of the vise and support shown in Figure 2 and as seen from viewing line 3-3 in Figure l.
Figure 4 is a phantom elevation similar to Figure 3 but showing the vise and support in an angular position.
Figure 5 is .another phantom elevation similar to Figure 3 but showing the vise and support in a vertical position.
Figure 6 is a top plan view similar to Figure 1 and illustrates the vise as it would appear when a cradle portion of the support takes the form of half-round saddles.
Figure 7 is an elevation of the vise and support as seen from the viewing of line 7-7 of Figure 6.
Referring now to the drawings, the vise assembly is placed on a drill press or other suitable bed fait. ln the assembly, a hemisphere ll lits into a spherical seat 12 of a wall member 32 of a cradle assembly i3. The cradle assembly t3 rests en the bed it) thereby supporting the vise. The assembly also supports a magnetic core ist around which is placed a winding l5. The source of current to the coil 15 may be from any suitable outlet of alternating or direct current. However, if alternating current is used, a suitable rectifying means must be provided.
In the specific embodiment illustrated, alternating current is fed from a terminal i6 and converted to direct current in a rectilier 17 which may consist of any of the common types of rectiiiers known to those skilled in the art. The current supply may be turned on or off by the operator by means of any suitable switch, illustrated here as switch 18. The ferrous magnetic core 14 is held to the frame ofthe cradle 13 by means of bolts i9. In order to prevent the magnetic ux from bypassing the hemisphere which supports the vise assembly, a bronze strip 20 is inserted into a gap in the wall 32 of the cradle assembly.
The vise itself comprises a stationary jaw 2l and a movable jaw 22 which is moved along a stationary guide block 23 by rotating a threaded member 24. The stationary jaw is connected to an upstanding lug on the hemisphere 11 by screws 25, while the guide block 23 is bolted to a flat side of the hemisphere lll.
In the operation of the invention, the workpiece'is properly located in a gap 26 between the movable and stationary jaws of the vise. The screw 24 is then rotated by a handle aixed thereto or by any other suitable means (not shown) until the movable jaw 22 grips the work. Without inal tightening of the movable jaw to the work, the switch 18 is closed, thereby causing direct current to flow through magnetic coil 15. This sets up lines of nur. in the ferromagnetic core 14 as indicated by the dotted lines 27, whereupon the hemisphere is locked to the cradle. Also, other uX lines 29 are directed through feet 28 of the cradle assembly i3 into the iron or steel machine-tool bed, 10 so that the assembly is prevented from sliding around when in use, and does not require clamping to the bed. The movable jaw may now be tightened by a swift or sudden motion and the ball will remain firmly fixed in its set position. When the operator is ready either to reposition or to remove the work holder he opens switch 18, thereby demagnetizing the magnetic core so that either the hemisphere may be rotated to any new position he may desire in order to place the workpiece in a more advantageous position or the hemisphere and work holder may be removed as a unit. In some cases there is a rather strong residual magnetism remaining in the structure, so it may be desirable to eifect demagnetization by applying alternating current to the coil 15.
Also if desired, a satisfactory level of residual magnetism can be made to exist with power off by providing a very small air gap of the order of .O02 in. between one end of the magnet core 14 and the frame of the cradle 13 to which the core is bolted. Such a gap would not yappreciably alfect the holding power of the device when energized, but would provide residual magnetism suflcient to properly hold the sphere 11 and the feet 28 of the cradle assembly when adjusting the particular part or tool involved.
Furthermore the cradle assembly 13 may rest on its face 30 `so that the wall 32 assumes an angular position as shown in Figure 4, or on its face 31 so that the wall 32 assumes a vertical position 4as shown in Figure 5. Thus the workpiece may be positioned as described by rotation of hemisphere 11 in its seat 12 in the wall 32 of the cradle assembly and also by placing the wall 32 in either a horizontal, vertical, or angular position. This highly desirable arrangement is made possible by the locking action of the magnetic forces set up when the core is magnetized. Thus, not only does this locking action allow disturbing the position of the hemisphere in the cradle, but it also permits the hemisphere to be fixed rmly in its seat regardless of whether the wall 32 of the cradle assembly is in a horizontal, vertical, or angular position with respect to bed 10. In the embodiment illustrated, the angle between face 30 and vertical faces 31 or 33 of the cradle assembly is shown as 22.5, but obviously the device may be constructed to provide other angular positions where desirable.
As hereinbefore mentioned the seat of the cradle need not necessarily be spherical but may also be of 'any other configuration which allows the hemisphere to freely rotate. A particularly desirable `configuration for the seat of the cradle is illustrated in Figures 6 `and 7 wherein a hemisphere 41 rests on a seat having the general configuration of half-round saddles. This type of cradle assembly is particularly desirable because it is simpler and more economical to build, causes less interference from the other parts of the assembly when it is desired to rotate the hemisphere, and concentrates the magnetic ux lines so that the hemisphere may be held more rigidly when the cradle assembly is magnetized.
Referring to Figures 6 and 7 in more detail, the vise assembly is placed on a drill press or other suitable bed 40. The hemisphere 41 tits into the saddle-shaped seat which is defined by surfaces 42 and 43 of half-round saddles of a cradle assembly 44. The assembly also supports a magnetic core 46 around which is placed a winding 47. The current is supplied to the winding by the method hereinbefore discussed in connection with Figure 3.
The vise itself comprises a stationary jaw 47' and a movable jaw 48 which is moved along a stationary guide block 49 and by rotating a threaded member 5i). VThe stationary jaw is connected to an upstanding lug on the hemisphere 41 by screws 51, while the guide block 49 is bolted to a ilat side of the hemisphere 4i.
The operation of the invention using this type of cradle assembly is essentially the same as that described in 'connection with Figures 1 5. n When the coil 47 is energized through a rectifier 60, ilux lines 53 are set up in the magnetic Lcore 46 and, when the hemisphere is in position, pass through the surfaces 42 and 43 thereby tightly locking the hemisphere in position. Other ux lines 54 are directed through feet 55 of the cradle assembly so that the assembly may also be held tightly to the bed 40. The concentration of the flux lines into the `cross-sectional area dened by the surface 42 has been found to be highly desirable as it creates a greater magnetic holding effect than heretofore realized. It will, of course, be obvious that the cradle assembly just described may assume the vertical or angular position illustrated in Figures 4 and 5.
While certain specific embodiments of the invention have been described and illustrated it will be understood to one skilled in the art that various modifications may be made, and I therefore desire to be limited only by the scope of the appended claims.
l. A universal support for a vise, said support comprising a hemisphere and a cradle, said vise comprising movable and fixed jaws mounted on said hemisphere; said hemisphere being positioned on spaced `and confronting concave seats formed in said cradle, said `cradle comprising spaced parallel side walls, a magnetic coil and a ferromagnetic core mounted between said side walls, and rectifier means mounted between said side walls to supply direct current to said magnetic coil, to lock said hemisphere rigidly to the seats of said cradle; said seats being formed in spaced supporting walls of the lcradle to provide a gap between each adjacent end of the spaced and confronting concave seats so as to prevent flux lines generated by said magnetic coil from bypassing said hemisphere.
2. The vise support as set forth in claim 1 in which the gaps between adjacent ends of the seats are occupied by a nonmagnetic solid material.
3. The vise support as set forth in claim 1 in which the spaced and confronting concave seats are positioned to form half-round saddles.
4. A cradle assembly containing spaced and confronting concave seats for a vise-supporting hemisphere, said cradle assembly comprising spaced parallel side walls, a magnetic coil and a ferromagnetic core mounted between said side walls, and rectier means mounted between said side walls to supply direct current to said magnetic coil, said seats being formed in spaced supporting walls of the cradle to provide a gap between each adjacent end of the spaced and confrontng concave seats so as to prevent flux lines generated by said magnetic coil from bypassing said vise-supporting hemisphere.
5. The cradle assembly as set forth in claim 4 in which the gaps are occupied by a nonmagnetic solid material.
6. The cradle assembly as set forth in claim 4 in which the spaced and confronting concave seats are positioned to form half-round saddles.
7. The cradle assembly as set forth in-claim 4 having both an angular and vertical outer face so as to make said vise support selectively positionable with respect to the horizontal.
8. A universal support for a vise, said support comprising a spherical segment and a cradle, said vise comprising movable and fixed jaws mounted on said spherical segment; said spherical segment being positioned on spaced and confronting concave seats formed in said cradle, said cradle comprising spaced side walls, electromagnetic means for locking said support Vrigidly to the seats of said cradle; said seats being formed in spaced supporting walls of the cradle to provide a gap between each adjacent end of the spaced and confronting concave seats so as to prevent flux lines generated by said electromagnetic means from bypassing said spherical segment. v
9. A cradle assembly containing spaced and confronting concave seats for a vise-supporting spherical segment, said cradle assembly comprising spaced side walls, References Cited in the le of this patent electromagnetic means mounted between said side walls, UNITED STATES PATENTS said seats being formed in spaced supporting walls of 807 517 V D 1 190 the cradle to provide a gap between each adjacent end 1 066951 Ramen lecl 1915 of the spaced and confronting concave seats so as to 5 2406008 EvVgode-t'gl Alllgy 20 192g prevent flux lines generated by sald electromagnetic 2,533,494 Mitchell Dec. 12, 1950 means from bypassing said vise-supporting segment.