# US 4,397,092 A · Caliper with dial indicator clamp and pistol grip > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,397,092 A - Document ID: US4397092A - Status: Granted - Kind: A - Application number: 06/275,852 - Filed: 1981-06-22 - Granted: 1983-08-09 - Earliest claimed: 1981-06-22 - Inventors: Stanley T. Marcyan - Web page: https://patentgrep.com/patent/US4397092A ## CPC - G01B 3/22: Feeler-pin gauges, e.g. dial gauges (for measuring contours or curvatures G01B5/20) - G01B 3/46: Plug gauges for internal dimensions with engaging surfaces which are at a fixed distance, although they may be preadjustable - G01B 5/12: internal diameters - Y10S 248/904: Indicator mount - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract Caliper with a pistol grip and a simple two-piece clamp for releasably securing a dovetail-equipped dial indicator thereto. The caliper fingers are stabilized and strengthened along their midlength by bracket plates fixed to the sides of one finger and embracing the sides of the other finger. ## Claims ### Claim 1 A clamp for releasably clamping a dial indicator to a machinist's tool comprising: an elongated tool member having an open-ended notch transversely thereof bridged by an open-ended female dovetail member extending lengthwise of said tool member and adapted to slidably seat a cooperating conventional male dovetail member rigidly attached to the main body of a dial indicator; said female member having a bore through the bottom thereof; a cap screw having its head positioned in said bore and its shank extending into said notch and including means for holding said screw against rotation; and a knurled nut rotatably mounted on said cap screw effective to hold said cap screw loosely assembled to said tool member and rotatable when the male dovetail member is assembled in said female dovetail member to force the head of said screw against said male member and clamp the same immovably but releasably in place in said female member. ### Claim 2 (depends on 1) A dial indicator clamp as defined in claim 1 characterized in the provision of means rigidly connecting said tool member to the opposite ends of said female dovetail member on the opposite sides of said notch. ### Claim 3 (depends on 1) A dial indicator clamp as defined in claim 1 characterized in that the head of said cap screw and said bore through said female dovetail member are non-circular and cooperate in restraining rotation of said cap screw during adjustment of said nut along the shank thereof. ### Claim 4 In combination, a caliper equipped with a precision clamp for a dial indicator comprising: a caliper having first and second elongated fingers pivotally interconnected between the forward and rear ends thereof; the rear end portion of said first finger being notched transversely thereof which notch is bridged by an outwardly facing female dovetail member open at either end and secured immovably to said first finger; a dial indicator having a male dovetail member mateable with said female member and having a needle operating probe seatable against a stop carried by the rear end of said second finger; a cap screw extending loosely and nonrotatably through said notch and through the bottom of said female member; and nut means on the threaded shank of said cap screw rotatable in one direction to shift one end of said cap screw in a direction to clamp said male and female members immovably together and rotatable in the opposite direction to release the clamping action between said male and female members. ### Claim 5 (depends on 4) The combination defined in claim 4 characterized in that said second finger includes a well and a threaded bore at points adjacent said pivot both extending toward the adjacent edge of said first finger; stop screw means in said threaded bore adjustable toward and away from the juxtaposed surface of said first finger; spring means in said well operable to bias said first finger against said stop screw means; and reinforcing plate means fixed to the opposite faces of said second finger in areas overlapping said well and said threaded bore. ### Claim 6 (depends on 5) The combination defined in claim 5 characterized in that said plate means extending along the opposite sides of said first and second fingers includes a pivot pin extending through said first finger and said plate means. ### Claim 7 (depends on 5) The combination defined in claim 5 characterized in the provision of pistol-type grip means secured to the rear end portion of said second finger, and trigger-like lever means movably supported on said grip means operable by the user's finger to contact the rear end of said first finger and pivot the forward end thereof in opposition to said spring means. ### Claim 8 In combination, a hand-held caliper comprising: a pistol type grip fixed to the rear end of one of a pair of pivotally connected fingers having the forward ends thereof spring-biased apart and against adjustable stop means; a female dovetail member fixed to the rear end of said movable finger. dial indicator means having a male dovetail member slidably seatable in said female member; nut and cap screw means operatively associated with said female member which nut is rotatable to advance said cap screw non-rotatably against said male member to lock said indicator means releasably assembled to said female member with the sensing probe of said dial indicator resting against an adjustable stop fixed to the pistol grip end of said caliper; and lever means on said grip manipulatable to pivot said movable finger away from said stop means. ### Claim 9 (depends on 8) The combination defined in claim 8 characterized in that said pivotally connected fingers include reinforcing plates fixed to the opposite sides of one of said fingers and movably embracing the opposite sides of the other finger and supporting the ends of a pivot pin on which said other finger pivots; and the opposite ends of said plates overlapping a spring well and a threaded bore for manually adjustable stop means mounted therein and which well and bore are located in one of said fingers and on the opposite sides of the pivot interconnecting said fingers. ### Claim 10 (depends on 8) The combination defined in claim 8 characterized in that said female dovetail member bridges a notch across one edge of said movable finger and is fixed to the opposite sides of said notch to reinforce the portion of said finger weakened by the presence of said notch.