US2011818A - Sprue former - Google Patents

Description

/1 w. G. MAISON 2,011,818

' SPRUE FORMER Filed July 21, 19:55

Mllllllll! INVENTOR,

Patented Aug. 20, 1935 UNITED STATES PATENT OFFICE SPRUE FORMER William G. Maison, San Francisco, Calif.

Application July 21, 1933, Serial No. 681,513

1 Claim. (01. 22-162) This invention relates to improvements in sprue top 3 concentric with the circles 2, which forms formers and is used by dentists and others, who a crucible when the investment is poured upon it. do small castings, to hold the sprue and to form The dome 3 is formed with a central vertical a perfect crucible for the molten metal. bore 4 which extends downwardly through the 5 The principal object of the improvements is entire thickness of the main body I and is adapted 5 to provide a sprue former capable of gripping to receive a dental burr 5, (shown in broken lines the groove or key at the large end of a dental Fig. 2), when used as a sprue. The head or burr (with the head or cutting blades removed), cutting blades of the burr 5 are removed so as when used as a sprue, so as to facilitate the to form a point or a continuation of the tapered handling of delicate wax patterns for small castshank which when heated is attached to the wax 10 ings commonly used in dentistry such as inlays, pattern. Positioned below the lower end of the crowns, etc. bore 4 and in space relation thereto is a lug 6 Other objects are to enable the user to easily rigidly attached to the bottom surface of the pick it up, set it down, or otherwise manipulate body I and so formed as to intercept the lower it, and to release the contra-angle dental burr end of the burr 5. Legs 1 support the main body 15 (with the head or cutting blades removed) when l in an elevated position on the table or work used as a sprue from the body of the sprue former bench allowing the sprue former to be easily with ease and rapidity, eliminating the necessity grasped and handled by the operator. A lever B of having to tap the base to free the sprue is fulcrumed on the base of the body I adjaformer from the casting ring and investment, cent to lug 6 by the screw 9. The end H] of the 20 thereby eliminating the cause of possible damage lever 8 extends parallel to and beyond the base to the investment around the sprue. of the body I and is curved to form a handle ll With the above and other objects in View, the which is adapted to contact a projection 12 on invention consists of the novel construction and the periphery of the body I. The end l3 of the combination of parts hereinafter described, illuslever 8 is formed with a notch M of smaller (11- 25 trated in the accompanying drawing, and set mension than the bore 4 and is adapted to engage forth in the claim hereto appended, it being the groove on the lower end of the burr 5 and understood that various changes in the form, serve as a latch when the handle H contacts the proportion, material, size, and minor details of projection I2. construction within the scope of the claim may I am aware that prior. to my invention sprue 30 be resorted to without departing from the spirit formers have been made in various sizes and maor sacrificing any of the advantages of the interials operating to grip the sprue pin or wire, vention. but none have been invented to grip the groove To more fully comprehend the invention, referor key at the large end of a contra-angle dental ence is directed to the accompanying drawing burr. I, therefore, do not claim such a com- 3 wherein:-- bination broadly.

Fig. 1 is a top plan view of my invention. I claim:--

Fig. 2 is a sectional view taken on line 22 of A device for the purpose described comprising Fig. 1. a base formed with a plurality of raised concen- Fig. 3 is a bottom view of the sprue former tric circles on its upper surface, a bore extending 40 showing the latch or lever in an engaged posithrough the said base, 2. lug formed on the under tion. surface of the said base and extending below the Fig. 4 is the same as Fig. 3 except that the lower end of the said bore in spaced relation latch or lever is shown in a disengaged position. thereto, the said lug being adapted to intercept Referring more particularly to the drawing, a dental burr, the head or cutting blades of which 45 wherein like characters of reference designate have been removed, or a mounted stone shank, corresponding parts, the base or main body porthe mounted point of which has been removed, tion I is formed on its upper surface with a pluwhen placed within the said bore, and means for rality of raised concentric circles 2, adapted to fit releasably retaining the said burr shank against 60 various sizes of casting rings. Extending upthe'said lug.

ward from the circles 2 is a spherical dome or WILLIAM G. MAISON.

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