US2561664A - Control means for dental engines and the like - Google Patents

Description

y 24, 1951 H. M. KECKLEY 2,561,664

CONTROL MEANS FOR DENTAL ENGINES AND THE LIKE Original Filed July 14, 1947 IN VEN TOR.

Patented July 24, 1951 UNITED STATES PATENT OFFICE CQNTROL MEANS FOR DENTAL ENGINES AND THE LIKE Harold M. Keckley, Findlay, Ohio, assignor to Wm. 0. Ballard, Toledo, Ohio 2 Claims. 1

This invention relates, as indicated, to control means for dental engines and the like, and more particularly to a foot-operated control device of a type adapted to permit considerable freedom of movement on the part of the operator.

In a co-pending application Serial No. 718,950, filed December 28, l946,'tl1ere is disclosed novel switch-operated means whereby the operator may control a dental drill or the like merely through the action of foot pressure upon a resilient elongated tubular member. As stated in such application, this tubular member may be filled with any of a variety of fluids, including air, for example. From the point of view of initial cost and maintenance, air is, of course, ideal but certain practical problems have been encountered in the use of pneumatic means, primarily due to temperature fluctuation. At times when such pneumatic system has been subjected to relatively high temperatures there has been a tendency for suflicient pressure to build up therein to shift the diaphragm to operate the master switch even though such resilient tubular member has not been subjected to foot pressure. On the other hand, at time of relatively low temperature the pneumatic system may become relatively insensitive and difiicult to operate due to the contraction in volume of the contained air. Both such conditions will, of course, depend upon the temperature at the time the system was sealed. It is very desirable to have a sensitively adjusted pneumatic system so that the operation of the dental engine or the like may be controlled simply by the pressure imposed by one foot of the operator as he stands by the dental chair.

It is therefore a primary object of my invention to provide control means for dental engines and the like including a foot operated pneumatic system which will be automatically compensated for ambient temperature variations.

Another object of my invention is to provide such control means which will be rendered inoperative to start the engine when the dental tool or the like is suspended from its usual support.

Other objects and advantages will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, said invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

Fig. 1 is a general perspective view of a dental chair and dental engine associated therewith showing a preferred arrangement of my new control device;

Fig. 2 is a diagrammatic layout of one embodiment of my invention employing an electric circuit as an element of the control means; and

Fig. 3 is another such diagrammatic layout of a system which is pneumatic throughout.

Referring now more particularly to such drawing, and especially Fig. 1 thereof, the master switch I of the motor controlling circuit for electric motor 2 is installed in the base of dental column 3 in the manner explained in the aforesaid co-pending application, master switch I corresponding to switch I6 of such application. Master switch I is a normally open micro-switch adapted to be operated by movement of diaphragm l inres'ponse to pneumatic pressure in chamber 5. Chamber 5 is connected to a resilient elongated tubular member 8 ordinarily of rubber and sealed at its other end to form a closed system. Such tubular member will preferably be arcuately disposed around the base I of the dental chair 8 and may lie beneath the rubber mat 9 ordinarily placed around such base.

The tool, such as dental drill I0 mounted on the end of jointed boom I I is supported when not in use by hook I2 carried by an upper extension of column 3. As explained in the co-pending application, such hook may be pivotally mounted to operate a switch in an electric circuit controlling the operation of the motor. The present invention, however, is concerned with means for controlling the pneumatic system itself.

Referring now more particularly to the Fig. 2 embodiment of my invention, a valve I3 is provided in tubular member 6 communicating with the outer atmosphere. An armature I 4 is pivoted at I5 to be rocked upon energization of solenoid IE to close valve I3. When such solenoid is not thus energized, spring Il acts on the armature to force valve I3 open. Valve I3 may, for example, be an ordinary automobile tire valve. The energization of the solenoid is controlled by switch I8 in the upper end of the dental column. Contact member I9 of such switch is forced open by the end of pivoted hook member I2 when the dental tool is hung upon such hook, as shown in solid line in Fig. 2. Consequently in this position solenoid It will not be energized and valve I3 will be held open so that tubular member 6 is in communication with the outer atmosphere. Foot pressure upon such tubular member, therefore, will be ineffective to operate master switch I when the dental tool is supported upon hook [2. When, however, the operator lifts the tool from such hook, spring 20 is effective to move the hook into dotted position, as shown in Fig. 2, and spring contact member l9 moves to close switch l8 and activate solenoid l6, thereby closing valve l3. Now that such valve is closed, operation of the dental engine may be initiated and controlled by means of foot pressure on member 6, as taught in the aforesaid co-pending application. Obviously the air entrapped in the pneumatic system will normally be under the same pressure as the outer atmosphere so that micro-switch I may be set for sensitive response to actuation of diaphragm 4.

Referring now more particularly to Fig. 3 of the drawing, the embodiment of m invention there illustrated is pneumatic throughout with out the employment of electrical control means. A small tube 2 I, which may be of metal or thickwalled rubber pressure hose is in communication with resilient tubular member 6 and terminates in the upper end of column 3 in a valve 22 which may be of the same type as valve 13, for example. When the dental tool is not hung from book l2, spring 20 will, of course, be effective to rock such hook out of engagement with valve 22. When, however, the dental tool is placed upon the hook, rotation of the latter will be effective to open valve 22 and place tubular member 6 in communication with the outer atmosphere. It will be seen therefore that foot pressure on member 6 will be ineffective to operate master switch I when the tool is hung from hook l2 and the pneumatic system will b automatically compensated for variations in atmospheric pressure. When, however, the tool is lifted from the hook the pneumatic system is at once closed and responsive to foot pressure on member 6 to move diaphragm 4 to close switch I It will be seen from the foregoin that I have provided control means for dental engines and the like employing a pneumatic system in which ambient temperature and pressure changes are automatically compensated for, and which is rendered inoperative when the tool connected to such engine has been hung upon its supporting means.

This application is a division of my copending application Ser. No. 760,816, filed July 14, 1947, Control Means for Dental Engines and the Like.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims. or the equavalent of such, be employed.

I therefore particularly point out and distinctl claim as my invention:

1. A dental engine, a power operated tool adapted to be driven by said engine, a movable support for said tool when not in use, pneumatic pressure means operative to control operation of said engine, and a vent for said pneumatic pressure means including a valve operable by movement of said support when said tool is placed thereon to vent said pneumatic pressure means to the atmosphere.

2. A dental engine including an electric motor, a power operated tool adapted to be driven by said engine, a movable support for said tool when not in use, pneumatic pressure means operative to control said engine, said means having a branch therefrom including a valve operable by movement of said support when said too] is placed thereon to vent said pneumatic pressure means to the atmosphere.

HAROLD M. KECKLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,856,869 Grimme May 3, 1932 2,092,948 Baitinger Sept. 14, 1937 2,444,188 Englund June 29, 1948

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