SUPPORT FOR SUSPENDED DENTAL SURGERY INSTRUMENTS

Abstract: The apparatus carries suspended power driven dental surgery instruments, and features a system whereby each arm (2) carrying a relative instrument (3) is split into at least two members (4, 5), hinged one to the other and provided with travel limiters and a return spring mechanism, such that when the power cable of the instrument is tugged by the user, the arm rotates by stages, with the member (5) farthest from the table (1) shifting before the member (4) to which it is hinged.

Description: The invention relates to a apparatus for the support of suspended power driven instruments, and in particular, instruments used in dental surgery, as disclosed in the first part of claim 1. Such an instrument is disclosed in the US-A-2 980 999. To provide a support for such suspended instruments, most manufacturers of dental surgery equipment and devices currently adopt a type of apparatus falling within a system that is generally known in Italy as SPRIDO (Strumenti Pendenti Recupero Inerte Doppia Operabilità, literally: Suspended Instruments, Inert Recuperation, Dual Operability). Such apparatus consists in a base, or table (usually associated with the equipment pedestal), and one or more arms, hinged to and projecting from the top of the table, each of which carries a power driven instrument (low speed and high speed drills, syringe, scale remover etc...). Each such arm pivots about a horizontal axis, and is subject to the action of a spring or counterpoise that balances the mass both of the instrument and of the supply cable connecting it with the table, in such a way that, when the grip is in use, the user will be aware practically of no more weight than that of the instrument held in his/her hand. This type of apparatus is highly practical, as it enables the user to effect operations repeatedly and precisely, even with frequent changes of instrument, and without experiencing any difficulty as regards manoeuvrability of the power cable connecting the instrument with the table. In addition, apparatus of the kind in question permits a fair amount of travel to an instrument when extended toward the patient from its retracted position, stowed at the table, to the operating position; thus, the user can work more quickly and efficiently, without continually having to adjust the position of the table. On the other hand, the arms of such apparatus reach a certain height when extended that can obstruct the movement and/or interfere with the field of action of other accessories, for example, the task light, generally embodied as an electric lamp carried on an articulated arm. The problem is a delicate one, inasmuch as accessory items such as these ought to be positioned and then left untouched, not least for reasons of hygiene. Attempts have been made to overcome this drawback by adopting flexible arms, i.e. embodied as springs, to replace the rigid type, though this too occupies considerable space in the height dimension, and by fitting the table with recuperator mechanisms that incorporate sliding pulleys and ways, though such arrangements are notably complex. Accordingly, the object of the invention is that of structuring the apparatus in such a way that its overall height will not give rise to the drawback described above. The solution to the problem to be solved is disclosed in the second part of claim 1. The stated object is achieved with an apparatus as characterized in the appended claims, in which the drawback in question is overcome by adoption of an arrangement whereby each arm is split into at least two spring-loaded, articulated members in such a way that when the instrument is taken up, the member farthest from the table will shift first. One of the advantages afforded by the invention is essentially that of simplicity, the result of which is that one obtains a highly functional apparatus. The invention will now be described in detail, by way of example, with the aid of the accompanying drawing, which illustrates the apparatus in cross section, and with certain parts omitted for the sake of simplicity. An apparatus according to the invention comprises a base, or table 1, which is hollow, and will normally be attached to the pedestal that carries the surgery equipment (not illustrated); the table 1 is rendered movable in relation to the pedestal by way of an articulated bracket 13, and is designed to carry one or more arms 2 each of which supports a suspended power driven instrument, or holder 3. The instrument 3 is connected with the inside of the table 1 by way of a power supply cable 11, this in turn connecting with the power sources and their control media (air, water, electricity), which are not illustrated. The cable 11 is supported by the table 1, and looped around a free pulley 12 mounted to the projecting end of the arm 2. The arm 2 is capable of movement between a lowered, stowed position (illustrated in bold line) and a position in which it is raised, or at all events, extended toward the user (phantom line). 15 denotes a task light, included in the drawing for added detail, which can be adjusted manually by way of a handle 16; positioned directly over the table, such a light constitutes a typical accessory item in dental surgery equipment. According to the invention, the arm 2 is split into at least two members 4 and 5 that are hinged one to the next about a pivot denoted 10a. Whilst the arm 2 is shown with two members 4 and 5 in the example of the drawing, a greater number could nonetheless be adopted, provided that the essential features of the embodiment as described below are retained. The innermost member, i.e. lying nearest the table 1 and denoted 4, is anchored to the table by way of an offset pivot 10; more exactly, this anchor pivot 10 is offset from the longitudinal axis of the arm to a degree such that the mass of the arm 2 alone will be sufficient to keep it biased firmly into the stowed, lowered position, i.e. farthest from the user. 6 denotes tensioning means that are located between the outermost member 5 and the table 1 and serve to balance the instrument and assist the return of the arm 2 (rotating toward the left, as viewed in the drawing); the means 6 in question are embodied as a spring 7, anchored at one end to the table 1, and a non-extendable element 8, anchored at one end to the outermost member 5 by means of an element 9 that permits of adjusting its length, and fastened at its other end to the free end of the spring 7. In the example illustrated, the element denoted 9 is embodied as a rotatable or ratchet-controlled pin, around which the end of the non-extendable element 8 is wound. This adjustment facility is of particular importance, since the force exerted by the spring 7 must be sufficient to sustain the mass of the cable 11 whenever the instrument 3 is in use (see configuration c ), and at the same time, to bias the arm 2 toward the stowed position when rotated to the left about its anchor pivot 10. The innermost member 4 is prevented from rotating beyond a given point by a travel limiter 17 forming part of the table 1 itself; a further limiter 17a curbs the rotation of the outermost member 5. With an apparatus embodied thus, it will happen that when the user takes up one of the instruments 3 and tugs on the cable 11, it is the outermost member 5 that rotates initially, and in relation to the innermost member 4 (configuration a becomes b ), following which the innermost member 4 will begin to rotate (configuration b becomes c ). Assuming the two members 4 and 5 to be of the same length, therefore, the maximum height reached above the table 1 will be substantially equivalent to the length of either one of the members 4 or 5, and in any event, much less than that reached by an arm 2 embodied in one piece. Expansion of the spring 7 is commensurate with the distance travelled by the non-extendable element 8, which wraps around the undersides of the two pivots 10 and 10a during the extending movement. When the instrument 3 is released by the user, the force developed through the tensioning means 6 will be increased initially by a slight thrust generated when the cable 11 is first motioned toward the table by the user, causing the member denoted 4 to rotate first, then the member denoted 5, so that both are returned to the lowered, stowed position denoted a . In an alternative embodiment, the innermost member 4 might be hinged to the table 1 at a point coinciding with its longitudinal axis, in which case it will be provided with spring means, operating independently if necessary, that invest the member 4 with a force, or at least a bias, greater than that developed by the spring 7.

Claims: 1. Apparatus for the support of suspended power driven instruments, in particular for dental surgery instruments, comprising a table (1) and an arm (2) comprising at least two articulated members (4, 5) hinged one to an other, the first member (4) to the table (1) and the second member (5) carrying a suspended instrument (3), said members (4, 5) being capable of movement between a retracted stowed position and an extended operating position, characterized by the fact that in said retracted stowed position, said first and second members (4, 5) are disposed substantiallay axially aligned with one an other and horizontally and parallel to said table and an extended operating position in which said first member (4) is rotated about a substantially horizontal axis to approximately a right angle with respect to said table (1) and said second member (5) is rotated about a substantially horizontal axis to approximately a right angle with respec to said first member (4) in the same plane; and at least one travel limiter (17, 17a) associated with said members (4, 5) and/or with said table (1), said at least one travel limiter being able to limit the rotation angle allowed to each member in relation both to the remaining member and to the table. 2. Apparatus as in claim 1, wherein the articulated members (4, 5) are subjected to return means in such a way that the first member (4) nearest the table (1) is biased continually in its substantially horizontally stowed position by a force greater than that applied to said second member (5) hinged to the first, and that the entire arm (2) is invested with a bias of an order, at least, such that when the instrument (3) is in use, the user need carry a weight no more than that of the instrument (3) attached to a power supply cable (11). 3. Apparatus as in claim 2, wherein said return means are realized by tensioning means (6) designed to offset a tugging action applied to the instrument power supply cable (11). 4. Apparatus as in claim 3, wherein said tensioning means (6) consist in a spring (7) anchored to the table (1), and a non-extendable element (8) made fast at one end to the spring, and anchored, at the remaining end, to an element (9) that permits of adjusting ist length and is fastened permanently to the member (5) of the arm farthest from the table. 5. Apparatus as in claim 1, wherein the first member (4) is hinged thereto about a pivot (10) that is offset upwardly from the longitudinal axis of the member itself, when the said member is positioned in its substantially horizontally position. 6. Apparatus as in claim 4, wherein the non-extendable element (8) is located below the pivots (10, 10a) about which the two articulated members (4, 5) are made to rotate, when said members are in their substantially horizontally position.

Inventors: CASTELLINI, FRANCO
Applicants: CASTELLINI S.P.A.
Application year: 1988
Main classification: A61G15
IPC codes: A61G15