US2106125A - Mechanism for grinding artificial dentures - Google Patents

Description

Jan. 18, 1938.

L. N. ROEBUCK ET AL MECHANISM FOR GRINDING ARTIFICIAL DENTURES Filed NOV. 17, 1936 Patented Jan. 18, 1938 MECHANISM FOR- GRINDING "ARTIFICIAL DENTURES Leslie Norman Roebuck, Melbourne, Australia, and Samuel James Everett, Thornton Heath, England; said Everett assigncr to said Roebuck Application November 17, 1936, Serial No. 111,326 In Great Britain December 5, 1935 8 Claims.

This invention concerns improvements in or relating to mechanism for grinding or finishing the teeth of artificial dentures of the kind in which one of the dentures is given a bodily rotary motion. By a bodily motion, in this specification, is meant a motion of translation, of which all parts of the carrier partake more or less in the same measure, as distinct from revolution about a single central axis. In mechanisms of this kind known or proposed heretofore, a bodily rotary motion has been imparted to a carrier for the denture with the assistance of an eccentric driving device and some form of guiding means. It is an object of the invention to provide an improved or simplified mechanism of the kind set forth.

According to the invention, grinding mechanism of the kind set forth comprises, in combination with driving means for the denture-carrier, resilient guiding means adapted for permitting the said carrier to rotate bodily whilst preventing revolution thereof about its axis. Preferably the said resilient guiding means is arranged in such manner that the carrier tends to be moved by the driving means with a bodily circular motion.

Thus, a rotary crank or eccentric may be pro vided for driving the carrier and the latter may be guided upon a support by means of an annular resilient coupling which surrounds the crank or eccentric and connects the carrier to the support in such fashion as to hold the carrier against revolution whilst permitting it to be rotated bodily, with a substantially circular motion, by the crank or eccentric.

Grinding mechanism in accordance with the invention may conveniently be incorporated in an articulator, particularly in an articulator of the construction described in the United States Patent No. 2,061,484 in place of the grinding mechanism illustrated in that patent. An embodiment of the invention devised more particularly for incorporation in such an articulator will now be described by way of example and with reference to the accompanying drawing, in which:-

Fig. 1 is a perspective view of the articulator and grinding mechanism,

Fig. 2 a transverse vertical section through the grinding mechanism, and

Fig. 3 a plan view of the said mechanism, as seen from below, with the carrier removed.

In the drawing, the support I for the grinding mechanism is illustrated as the upper frame- 5 member of the aforesaid articulator. Secured tothe support l is a cylindrical bearing 2 for a r0- tatable cylindrical body 3 which is conveniently formed in one piece with a driving member which, as shown, is a pulley 4. The latter is arranged to bear upon the upper end of the bearing 2. The cylindrical body 3 has an eccentric bore 5 through which projects a pin 6 having a carrier 1 for the upper denture screwed upon its lower end. The carrier may have the form of a flanged plate and may be provided with clamping screws 8 for engaging posts 8 which projects up Home. removable ring 1 into holes in the plate 7. The pin 6 passes right through the cylindrical body 3 and bears with its head 9 on the pulley 4. By this means, the carrier i is firmly, although detachably, secured in relation to the support I.

A soft rubber ring it is arranged around the periphery of the space bounded by the support I and carrier 1 and the abutting flanges l2, l3 thereon. The ring ll overlaps both of the flanges (Fig. 2). The support and carrier are provided respectively with pins. it, l5 which project into alternate holes it, i"! in the rubber ring H. This arrangement constitutes the resilient guiding means or coupling. The pins l4, l5 should be substantially evenly spaced around the ring, so that they resiliently locate the carrier, 1. e. permit the carrier to be moved a short, distance in its own plane with equal freedom in all directions, but prevent the said carrier from being revolved about its central axis. In other words a definite preset orientation of the carrier 1 in relation to the support I is maintained by the resilient guiding means or coupling, The rubber ring l l is preferably slightly compressed between successive pins H3 or 55 on the support or carrier.

When the cylindrical body 3 is rotated by driv: ing the pulley t, the pin 6 is carried round; in a circular path by the eccentric bore 5. On account of the above-described arrangement of the. rubber ring I l, the carrier '5 cannot revolve about its axis. The resilience of the said ring, however, permits the carrier to follow the motion of the pin by a bodily or translatory circular motion. As will be understood, the circular motion of the carrier 1 is of small amplitude suitable for effecting a grinding action between the surfaces of the upper denture carried thereby and those of the lower denture carried on a fixed lower support, but is insufficient for causing destruction of the cusps of the teeth. Such circular motion of the carrier 1 gives a generally efiective grinding action, but it will be appreciated that the motion performed by the said carrier may not always be perfectly circular, as the dragging action of the teeth upon one another during grinding may modify the motion to a greater or less extent. The resultant grinding action may thus adapt itself in some measure to the varying conditions during grinding.

The necessary movements of the teeth corresponding to movements thereof which occurin natural chewing are effected manually. As described in the above-mentioned specification,

for instance, the upper and lower dentures are mounted in correct relative positions in the articulator and the upper frame-member l of the said articulator is moved during the grinding process. In the articulator illustrated, this is effected by adjusting the screws IS. The latter act upon the frame-pivots I9 which are guided in the slots 20 and are also acted upon by springs 2!. By this means, movements of natural chewing can be simulated, so as to ensure that the finished teeth will be free from any tendency to lock together in any position when in use.

To permit of the carrier 1 being secured in a predetermined position corresponding to central occlusion of the dentures, a locking pin, for example a set-screw 22, is mounted in the cylindrical bearing 2 and is adapted. for being engaged in a recess 23 in the cylindrical body 3 when the latter is in the position corresponding to central occlusion. The said recess and the extremity of the screw entering it are preferably made of rounded or conical shape, as shown, so that the act of tightening the screw will force the cylindrical body 3 accurately into the position corresponding to control occlusion. An initial approximate positioning is performed by rotating the pulley 4 until an arrow 4 thereon points to the rear. An oiling duct is indicated at 24 and a loading weight at 25.

Various modifications may be made within the scope of the invention: The rubber ring may engage in formations on or in the support and carrier, for example circular grooves therein: More than one rubber ring may be provided: The ring may be compressed between the support and carrier: The grinding mechanism described may obviously be incorporated in or mounted on articulators constructed differently from that described in the aforesaid specification.

The above described locking means 22, 23 may permit a slight oscillatory motion of the carrier 1. If it is desired that even this motion should be excluded, provision may also be made for locking the carrier 1 to the frame I by means of a screw which passes through a large hole in the latter, behind the bearing 2, and engages in a tapped hole in the former, the head of the screw bearing upon the frame I by way of a washer.

We claim:-

1. Denture-grinding mechanism comprising, in combination with a denture-carrier and driving means therefor, resilient guiding means for the said carrier adapted for permitting the carrier to be rotated bodily by the driving means whilst preventing revolution of the said carrier about its axis.

2. Denture-grinding mechanism comprising, in combination with a denture-carrier and driving means therefor, a support and a flexible ring arranged between the said carrier and support and adapted for permitting the carrier to be rotated bodily by the driving means whilst preventing revolution of the said carrier about its axis.

3. Denture-grinding mechanism comprising a support, a denture-carrier, rotary driving means for the said carrier, a flexible coupling ring located between the support and the carrier, and means for anchoring the said ring at intervals to the support and carrier.

4. Denture-grinding mechanism comprising a support, a denture carrier, rotary driving means for the said carrier, a flexible coupling ring located between the support and the carrier and formed with apertures at intervals, and anchoring bodies provided on the support and carrier and extending from the said support and carrier into alternate apertures in the flexible coupling 4 ring.

5. Denture-grinding mechanism comprising a support, a denture carrier, rotary driving means for the said carrier, a flexible coupling ring. located between the support and the carrier, and means for locating the said carrier in relation to the said support, the flexible coupling ring being under an initial compression between the support and the carrier located thereon.

6. Denture-grinding mechanism comprising a support, a denture-carrier, a rotatable body with an eccentric bore, a pin extending into the said bore and connected at its lower end to the carrier and supported at its upper end by the rotatable body, and a. flexible coupling means located between the said carrier and the support and adapted for permitting the former to rotate bodily but not to revolve in relation to the said support.

7. Denture-grinding mechanism comprising a support, a denture-carrier, rotary driving means for the said carrier, resilient guiding means between the said support and carrier adapted for permitting bodily rotation of the carrier, and locking. means for securing the carrier in relation to the support in the position corresponding to central occlusion.

8. Denture-grinding mechanism according to claim 7, wherein the locking means comprises a set-screw with a shaped extremity engageable in a complementary recess in a rotatable part of the driving means.

LESLIE NORMAN ROEBUCK. SAMUEL JAMES EVERETT.

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