US1177706A - Porcelain-crown remover. - Google Patents

Description

J. A. JOHNSON.

PORCELAIN CROWN REMOVER.

APPLICATION man FEB- 7, 1916.

1,177,706. Patented A r. 4, 1916.

ml: COLUMBIA PLANOGRAPH cm, WASHINGTON, D. c.

UNITED STATES PATENT OFFICE.-

J'OHN A. JOHNSON, OFCHICAGO, ILLINOIS, ASSIGNOR TO GOLDSMITH BROS. SMELTING 6'6 BEFINING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

PORCELAIN-CROWN REMOVER.

Patented Apr. 4, 1916 Application filed February 7, 1916. Serial No. 76,711.

To all whom it may concern:

Be it known that 1, JOHN A. JOHNSON, a citizen of the United States, and a resident of the city of Chicago, in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Porcelain-Crown Removers, of which the following is a specification.

This invention relates broadly to dental tools, and more particularly to an instrument for removing porcelain crowns.

The principal object of this invention is to provide an instrument for the removal of a porcelain crown which may be desired to be removed from the tooth on which said crown has been permanently set.

A further. object of this invention is the production of an instrument of the character specified wherein the porcelain'crown is removed by gradually forcing a wedge between the base of the crown and the tooth by means of relative movement between an abutment and a wedge member, both of which are carried upon devices which extend to one side of the tooth being operated upon.

A still further object of the present invention is the production of a porcelain crown remover wherein the operating jaws are carried upon body members which extend substantially parallel and to one side of the zone of operations of said jaws.

A still further object of the Present invention is the production of a porcelain crown remover comprising a pair of operating jaws, one of which is wedge shaped, and wherein one of said jaws is carried upon a bar adapted to extend over the crown being operated upon and at substantially right angles thereto.

7 A still further object of the present invention isthe provision in a porcelain crown 1 remover of a pair of jaws, one of which is wedge shaped, and the jaw adapted to engage the lingual side of the tooth being carried upon a member-extending at right an- I gles toland over the top of the crown, and

the jaw engaging the labial side of the tooth' being carried upon a member having slidable engagement with the first mentioned member, and wherein a thumb screw is provided to cooperate with said members to close said jaws.

Other and further objects of the present lnventlonwlll 1n part be obvious and will in part be pomtedxout hereinafter in the specification by reference to the accompanying,

drawings wherein like parts are represented by like characters throughout the several vlews thereof.

Figure 1 is a perspective view illustrating construction to spring tweezers with a pair of lnturned aws at their inner ends and provided with a clamp screw whereby the jaws might be closed. With devices of this.

kind it is diflicult to insert the instrument in the patients mouth and properly seat the jaws in position to displace the crown. One of the chief reasons for this difliculty is the fact that the body or main portion of theiinstrument extends substantially in the direction of the axis of the tooth and consequently in line with the correlated tooth in the opposite jaw. Also in thistype of crown remover there ismore orless deviation of the operating jaws from their normal movement, due to the spring of the tweezer part of the body portion thereby to a certain ex tent destroying the positive action necessaryv to loosen the cemented crown from its pos'ition on the tooth. Furthermore, removers of this character lack a rigid hand hold one side of a rigid body portion which ex tends substantially parallel to the said j aws.

whereby the insertion and manipulation of the instrument in the patients mouth is greatly facilitated. 'Furthermore', my invention includes a construction in which the jaws are constructed to be positively closed by endwise movements of rigid parts thus establishing a positive forcible actlon of the jaws and overcoming the'difiiculties encountered due to springing of parts under presbod-V porfion'so flp e instrument may b positively and" definitely operated.

Referring now more'particularly to the,

drawings the bar 1 is preferably square in cross-section. and, at its inner end carries a right angle extension 2 on' the end of which isa jaw 4 constructed to engage the lingual side of theotooth and which preferably extends substantially parallel to the bar. 1. The inner end of the'bar l is cylindrical and provided with screw threads 5 with which is engaged the thumb nut 63* that bears against the outer end of the square sleeve or tubular member 7. This tubular-member 7 has an interior cross section very slightly larger, than the cross-section of the bar 1 so that th'ebar 1 snugly'fits within the'tubular member'for sliding engagement therewith and the outer end 8 of the tubular member Zis filledto provide a shoulder'9 to com- I prise an abutment so that the spring 10 hear,-

ing against the shoulder 11 tends to substantially urge the bar inward thus seatlng the thumb nut 6 firmly against the outer end of the tubular member. The inner' end of the tubular membercarries an off-set extension 12 on which ismounted a wedge shaped jaw 14 that is adapted to engage the labialside of the tooth at the junction line between the tooth 15 and the porcelain crown 16 thus wedging the crown loose from its position upon the tooth. In order to accommodate the crown pin 17 it is necessary that one of the operating jaws be'bifurcated' and thereforeI have illustrated the jaw 14 as'being provided with a slot 18. Sinceit is desirable that the operating jaws be constructed so that one jaw will pass the other, I have illustrated the jaw 4;as being constructed to pass over the jaw 14. To facilitate manipulation I have providedthe tubular member 7 with finger; rings 19, rigidly secured thereto, so that these rings maybe used ashand holds so that the instrument may be given a rocking motion to make the action of the wedge elements most efi'ective. 1

Realizing that it is possible to vary the physical embodiments of my invention without departing from; the spirit thereof, I desire-that the specific construction herein shown and described shall be understood as being illustrative and not in the limiting sense.

-;Having thus described my'invention what F1; In device of thefcharacter described,

in combination, asquare bar provided with an off-set portion, a aw on the end? of said off-set portion adapted to engage the lingual 7 side of'the tooth, a tubular member having a squarecross-section openingw-ith-in which said square bar is adapted tos'lide endwise,

an ofi-set member carried by said tubular" memberand provided on its end with: a wedge shaped aw constructed to engage a tooth on the labial side and to separate a cemented;porcelaincrown from the tooth to V which it is anchored, a screw threaded portion upon said square bar,jand"extending b yond' the end of said tubular 'member, a"

thumb screw constructed to co-operatetwith said'threaded portion to drawsaid' bar outwardly relative to said tubular member thereby causing said jaws to positivelyxclose,

a coil spring within said tubular'member and bearing agalnst said square bar tocon stantly exert pressure tending to opeii'isaid jaws and to seat said thumb screw against said tubular member, and a hand. hold formed upon saidtubular member: to enable saiddevice to, be manipulated.

' 2'. In a djvice, of the character described,

inrcombination, a square barprovided was tially parallel to the axis'of said bar, alt ubus 1n member having the: opening itherein" square shaped in cross-section and within which said bar is adapted to slide, a jaw" mounted upon and off-set; from said-tubular member and being opposed to the first'mentioned jaw, said jaw extending parallel/to the axis of the bar, and means togradually ii and positively close said jaws.

8. In a deviceof the character described,"

in combination, a rigid-bar provided with an off-set portion carryinganioperatingjaw extending paralleltothe axis of the bar, V a; member secured-to and mounted to slide relatively to said bar, said member-carrying a aw adaptedtobeopposed to the firstmentioned aw and also'extendingparallel tozthe axis ofthe bar, and meansfor'graduallylandf positively moving said; bar and said mem bar relative each r o effecta Positive 7 ii In a device of the character'described,

gradual and closing movement of 'saidjaws.

in combination, a pair of operating jaws, supporting members for said jaws extending to one s'ideof theoperating zone ofsa i-d jaws'and parallel to the operative move ment' of-the jaws, and means cooperating with said supporting members 'to' gradually and positively close said jaws.

5. In a porcelain crown.- removergincorm binatlon, a pair of jaws, lone-of which is we'dgeishaped, said wedge shaped jaw being provided with a slotted opening, supporting 7 members for 'both of said jaws, said sup;

P embers extending to 1 one sid of the zone of operations of said jaws a d parallel to the movement of the jaws, a pair members carrying said jaws, said jaws being of hand-holds secured to one of said supconstructed to permit one jaw to slide over porting members, and a thumb screw for the other, a spring cooperating with the said 1 positively closing said jaws. members and tending to open said jaws, and

5 6. In a porcelain crown remover, in coma thumb nut for positively closing said jaws.

bination, a pair of opposed jaws, one of which is wedge shaped, a pair of sliding JOHN A. JOHNSON.

copies of this patent may be obtained for five cents each, by addressing the "Commissioner of ratents, Washington, D. 0.

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