US61799A - boardman - Google Patents

Description

H.A.BOARDMAN.

Calipers.

Patented Feb. 5,1867.

N PETERS PHD gaunt @ffite.

IMPROVEMENT IN OALIPERS.

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1'0 ALL WHOM IT MAY CONCERN:

Be it knofwn that I, H. A. BOARDMAN, of New Haven, in the county'of New Haven, and State of Connec= ticut, have invented new and improved Calipers; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, reference being had to the accompanying drawings, forming part of this specification: I

The present invention consists principally in the combination, with the arms of the calipers, of a screwthreaded shaft that at one end is secured to a loop swivelled or pivotedto one of the arms of the calipers, and, passing therefrom loosely through a loop similarly hung to the other arm, has screwed upon its outer and loose end a milled nut, by the turning of which upon the said screw-shaft, either to the right or left, as the case may be, the arms of the calipers can be either closed or allowed to open by the action of a spiral or other spring suitably attached or connected to them therefor.

This invention also consistsin a novelomannerof connecting and combining the arms and spiral spring of the calipers together, as will be hereinafter explained. In the accompanying plate of drawings my improved calipers are illustrated- Figure 1 being a front view ot the same with a portion in section to show the arrangement of the spiral spring for throwing open the arms of the calipers; and

Figure 2, an edge view with the same portion in section as that shown in fig. 1, but in a (lifi'erent plane.

Similar letters of reference indicate like parts.

A A, in the drawings, represent the twoarms of the calipers, both of which are made of a similar curved shape, and are hung at one end to and upon a common centre-pin or pivot, B, by which they are also secured and held together with a barrel, collar, or ring, (1, between the two, forming a suitable box or casing, D, to receive and hold a spiral spring, E, which surrounds the said centre-pin B Each end of the spiral spring E is made of a hook-shape, so as to interlock with pins a oi: the caliper-arms, one with one of the said arms and the other with the other of the same, in such a manner as to swing or open the arms from each other by its pressure or tension. F a screw threaded shaft, which at one end is secured to a loop, G, swivellcdor pivoted to one of the arms of the calipers. This shaft F passes loosely through another l'oop, H, swivelled to the other arm, when upon its outer end a milled nut, I, is screwed, by the'turning of which, either'to the right or left, as the case may be, the arms of the calipers can be closed or allowed to open'from each other by the action of the spiral spring E, according as may be necessary or desirable, the said nut holding the arms of the calipcrsx at whatever position they may be brought or adjusted by the turning of the same. By passing the screw-threaded shaft through a loop swiyelled to one of ,the arms of the calipers, and hanging or securing it to a similar loop of the other, all strain upon the said shaft is avoided, and it is capable of adjusting itself in position according as the arms of the calipers are more or less open. By hanging thespiral spring E, used in the manner above described, to .the two arms of the calipers, or in an equivalent manner thereto, I- a m'enabled to use a barrel or.

collar, C, for enclosing it, made in one entire or continuous piece of metal or other suitable material, whereas, in all calipers, as hitherto made, as the spring. was hung or connected to the barrel or collar in some manner, such barrel usually constituted a part or was formed upoupnc of the arms, and at some points of its length was slotted or opened. In order to fully; insure the retention of the barrel C in position between the arms of the calipers, without requiring the arms to be tightened upon it by their centre screw to such a degree as to prevent their free action or play, I deem it best to bevel the edges of the collar as well as the surface of the arms with which it comes in contact to such an extent and in such directions as to prevent the collar from slipping or moving laterally evon'if the arms are left rather loose or free to turn, the advantages and importance of which are obvious.

Although I have herein particularly explained my improvements in connection with calipers, it is obvious that they may be used or adapted as well to compasses and other similar instrument s.

What I claim as new, and desire to secure by Letters Patent, is-

The barrel or collar C when made in one'entire or cont nuous piece and independent oh the caliper arms, and secured thereto substantially as and for the purpose described.

' H, A. BOARDMAN.

Witnesses PHILIP Penn, CHARLES C. Btsrennsr,

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