Machine vise protractor

A machine vise protractor which can be installed onto and removed from the base of a machine vise while the vise is mounted on a table, to permit rotating the vise about a known center point to a desired angle. The protractor assembly is easy to make, can be adapted to a wide number of machine vises, and can be removed once the vise is properly located to keep the table uncluttered while the vise is clamped in place. The protractor can also be used with a plurality of vises for setting up several machine tools, or with several vises on the same machine tool without incurring the expense of separate protractors for each vise.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to simplified, removable protractors that can 
be used with machine vises for adjusting the angular position of the 
vises. 
2. Prior Art 
Machine vises have long been mounted on protractor bases which raise the 
vise body up from the table on which it is mounted, but which permits 
angular positioning of the vise relative to a reference position. 
In many of the bases used, a centering pin is fitted into a receptacle on 
the bottom of the vise body. This same receptacle and provided slots in 
the vise base are utilized with the present protractor. The slots in the 
bottom surface of the vise extend out to the peripheral edges of the vise 
for use with the present device. 
SUMMARY OF THE INVENTION 
An easily utilized and multiple purpose protractor member for use with 
machine tool vises comprising a flat plate having angle indicia around a 
peripheral edge, and means for locating the member in a known relation to 
the vise center. The plate is held relative to the vise with interlocking 
tongue and groove members. A separate indicator can be utilized in a tool 
table slot in connection with the indicia to indicate the angular position 
relative to a reference position. 
As shown, the vise is also centered on a pivot pin member mounted in the 
machine tool table. 
Specifically as shown, slots which are formed on the bottom surfaces of 
many vises are extended to the edges of the vise and two such slots 
positioned at 90.degree. to each other and intersecting at the center of 
the vise are for mounting the protractor. The protractor member has a 
first fixed tongue which fits into one of the slots, and a telescoping or 
retractable tongue that may be extended to fit into another slot on the 
vise to permit the protractor member to be attached to and removed from 
the vise quite easily.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A protractor assembly indicated generally at 10 includes a planar 
protractor plate 11, and an indicator 12 used in connection with outer 
angle indicating indicia 13 which is placed on the protractor plate 11 
adjacent to the outer part circular peripheral edge. The protractor itself 
is used in connection with a vise 15 having a base 16 which is provided on 
its bottom surface with a receptacle for receiving a headed centering pin 
17. The receptacle on the bottom of the vise is centered along the central 
axis 18 of the vise 15. The vise 15 has suitable jaws which were indicated 
generally at 20, and a movable jaw 21 can be actuated in a desired manner 
toward and away from the fixed jaw. 
The vise 15 is adapted to be mounted onto a machine tool table indicated 
generally at 25 which as shown has a plurality of inverted T shaped slots 
26 defined therein. The cross sectional shape of the slot is shown in FIG. 
4, and the inverted T shaped slots are conventionally used for clamping 
vises and other members onto machine tool tables. 
The vise base 16 besides having the receptacle for holding the pivot or 
centering pin 17 in place is provided with slot means that open to the 
outer edges and have center lines which intersect at the axis 18. For 
example in the form shown, there is a slot 27 that extends transversely 
across the narrow dimension of the vise, which is shown in dotted lines in 
FIG. 1 as well as in solid lines in FIG. 2, and a slot 28 which is 
perpendicular to the slot 27. 
The slot 28 is longitudinally extending and in the form shown can extend 
all the way along the length of the vise base, or if desired it could 
terminate short of the center portions of the vise. It is required that 
the slot has a slot end portion that opens to the peripheral edge of the 
vise base. It should also be noted that the head of the pivot member or 
pin 17 should be of sufficiently large diameter so that the pin will stay 
in position at the intersection of the slots 27 and 28, so preferably the 
head is of larger diameter than the width of the slots. 
The protractor plate 11 includes a main portion 31, and an end portion 32. 
The main portion 31 extends along the longitudinal edge of the vise 15, 
adjacent to the perimeter of the vise, and the end portion 32 extends 
around one end of the vise. The protractor plate 11 has edges which extend 
along two generally mutually perpendicular edges of the vise. On the end 
portion 32 of plate 11, an inwardly directed tongue member 33 is provided 
which is of size to closely fit within the slot 28. The tongue 33 extends 
into the slot 28 only a short distance, but the tongue holds the 
protractor plate 11 quite securely from transverse movement laterally of 
the vise. 
The main portion 31 of the protractor plate 11 has a slide bracket 34 
mounted thereon, and a retractable tongue 35 is slidably mounted in the 
slide bracket 34 and has a control knob 36 which extends upwardly above 
the slide bracket. The control knob 36 is fastened to a shaft 38 which 
extends through a provided slot 37. The tongue 35 can be retracted so that 
the end of it clears the side edge of the vise base 16 which is adjacent 
the aligning edge or corresponding edge of the protractor plate. 
When tongue 35 is retracted, the tongue 33 also can be longitudinally slid 
out of the slot 28 so that the protractor member can be removed completely 
from the vise. 
When the plate 11 is again placed flush along the top of the table 25, with 
the tongue 33 in the slot 28, the tongue or key 36 can there be moved to 
its dotted line position shown in FIG. 3 (or its solid line position shown 
in FIG. 2), so that the tongue or key enters the end of slot 27 and 
positively latches the protractor plate 11 in position relative to the 
center axis 18 of the vise. 
The center lines of the tongues 33 and 35 also intersect at the axis 18, 
which is the central axis of the vise perpendicular to the table 25. 
The indicator 12, as shown, is generally T shaped and has a narrow neck 
portion 12A which fits within the top portions of the slots 26, and the 
top part of the indicator 12 has a needle or indicator pointer 12B that is 
positioned closely adjacent the peripheral edge of the protractor plate 11 
and thus adjacent the indicia 13 so that it can indicate the angular 
position of the longitudinal axis of the vise, which is the axis passing 
through axis 18 and perpendicular to the faces of the jaws 20. Once the 
vise is in position, suitable clamps indicated at 40 can be used for 
clamping the vise in position in a normal manner. The clamps 40 are shown 
only schematically, but include threadable members that are threaded into 
retainer clips or lugs 41 within the slot 26 of the table, and clamp the 
outer extending end portion of the clamps 40 against the base 16 of the 
vise. 
Thus in combination, the vise base includes centering means for permitting 
rotation about a center axis located relative to the table slots 26, and 
the protractor plate is provided with keys or tongues that fit into 
provided receptacles on the vise that mate with these keys or tongues and 
hold the protractor plate in the desired position with the reference or 
zero indicia aligned along one axis of the vise that is at a known 
coordinate relative to the vise jaw faces. As shown, the zero indicia is 
along a plane parallel to the vise jaw faces, but zero could be the 
indicia perpendicular to the vise jaw faces if desired. 
At least one of the tongues on the protractor plate is retractable to 
permit the protractor plate to be easily removed or installed relative to 
the slots or keyways on the vise base. An indicator which is stationary on 
the table when the vise and protractor plate rotate is mounted in a 
reference location relative to the center axis of the vise. The slots and 
tongues form interlocking, cooperating tongue and groove means between the 
vise and the protractor plate to securely hold the protractor plate in 
position. 
The protractor plate is easy to use, and economical to make, as well as 
being usable with several vises.