Claims:
What I claim and desire to secure by Letters Patent is
1. A holder assembly for at least two dental tools comprising base means, holding means on said base means for holding dental hand pieces on said base means, shaft means mounted on said base means, at least two rigid support members rotatably mounted on said shaft means, each of said support members having an opening on its upper portion and a protrusion on its side portion, rigid tube means mounted in each of said openings of said support members, at least one adjustable counterweight means rotatably mounted on said shaft means for counterbalancing said counterweight means having a channel wherein said protrusion is seated, said channel extending rearward of the direction of rotation of said support members so as to permit initial free rotation of said support members and engagement of the walls of said channel only at beginning of counterbalancing activity and counterbalancing only the support members working, and flexible tubes whereby the connection of the hand pieces to a power source is carried through the openings in said support members, the rigid tube means and the flexible tubes.
2. A holder assembly for two dental tools comprising base means, holding means on said base means for holding dental hand pieces on said base means, shaft means fixedly mounted on said base means, two rigid support means rotatably mounted on said shaft means, each of said support means having an opening on its upper portion and a protrusion on its side portion protruding toward each other, an adjustable counterweight means rotatably mounted between said support means for counterbalancing said counterweight means having a channel therethrough and extending rearward of the direction of rotation of said support members in which each of said protrusions are seated so as to permit free rotation of each of said support members before the counterbalancing begins and to counterbalance only the support member working, and flexible tubes mounted on each of said rigid tubes whereby the connection of the hand pieces to a power source is carried through the openings in said support members, the rigid tubes and the flexible tubes.
Description:
This invention relates to a holder assembly for dental tools, such as dental engines, air and water syringes etc., which are fed through elongate flexible connections each drawn up to the holder assembly.
The term "elongate flexible connections" as used herein is meant to cover air and water hoses, power supply cords, etc.
It is customary to dispose all the tools of the above mentioned kind which are required in dentistry on a holder assembly pivoted to the dental chair and readily brought into a suitable working position. The tools primarily concerned are dental engines of the compressed air type now predominating, and air and water syringes, but other types of course are also conceivable.
The use of the equipment is facilitated if the dental tools in question are of low weight, easy to grasp and provided with light-weight hoses or flexible cords. In the absence of a holder assembly the hoses hang freely between the compressor and/or pump unit and the tool used. It is also known to load the hoses with weights and to let them run over rollers for retraction. If the dental engines and the syringes are disposed on a holder assembly the freely hanging hoses are dispensed with, and the relatively short hose lengths can be wound onto a number of reels built into the assembly. When the dental engines and syringes are not in use the hoses are kept stored in the assembly, the tools being usually placed in the insertion holes of the hoses.
A serious drawback of these known arrangements is that the hoses and cords and their weight are troublesome in the sensitive work carried out by a dentist. The ideal solution of course would be to use the tools as if they were not connected to any hoses or cords, that is to say the weight, length or run of the hoses or cords must not affect the handling of the tools and thus have a tiring effect on the operator. Naturally, they should not either come in contact with the patient. To facilitate grasping and replacing the tools the tool holder assembly proper should be so designed that the dentist is able to both grasp and replace the tools without moving his eyes from the work he is doing.
In an earlier attempt at overcoming the above-mentioned drawbacks and satisfying the requirements made the hose and cord lengths running from the holder assembly to the tools are supported each by an elastic support member protruding from the holder assembly, such as a coil spring.
Of course, such an arrangement implies considerable advantages in relation to the prior-art devices, but it does not constitute an ideal solution. The support spring is disadvantageous first of all because movements of the tool readily give rise to oscillations of the spring, which results in jerks at the hose or cord. Another disadvantage is that it is not possible to attain the desired total counterbalancing of the weight of the hoses or cords. Also, a relatively small working range only may be counterbalanced by means of said spring.
The above-mentioned drawbacks of the prior-art construction described are overcome by means of the holder assembly suggested by the present invention. This holder assembly is characterized in that a protruding rigid support member for supporting the hose or cord length is rotatably mounted on a shaft of the holder assembly and via a laterally protruding pin or rib engages biasing means generating a force the size of which is adapted to counterbalance the weight of the hose or cord length and the support member, the engagement being such that the support member and the biasing means are interconnected in that angular range of the rotary movement of the support member which corresponds to the working range of the tool, but are released from another in that angular range of the rotary movement of the support member which corresponds to replacing the tool into position of readiness.
The invention will be described more in detail in the following, reference being had to the accompanying drawings in which:
FIG. 1 is a perspective view of a first embodiment of a holder assembly as seen from the rear;
FIG. 2 is a perspective view, as seen obliquely from in front, of the main constituents of the holder assembly in a partly exploded state;
FIG. 3 is a side view, partly in section, of a second embodiment of the holder assembly.
In the embodiment shown in FIGS. 1 and 2 a baseplate 1 has two upstanding side members 2 for supporting a shaft 3. Two support members 4 and an interjacent balancing member 5 are disposed on said shaft 3. Each support member 4 consists of a body portion 6 and a rigid tube 7 protruding therefrom, through which passes a hose or cord 9 leading to a tool, such as a handpiece 8, and anchored at the outer end of the tube by means of an elastic sleeve 7', said hose or cord 9 extending approximately diametrically through the body portion 6 and from there to a source (not shown) of electric power, air, water or the like. The body portions 6 and the balancing member 5 are mounted on the shaft 3 by means of ball bearings 10 to eliminate friction.
In FIG. 1 the tubes 7 are shown in position of readiness, i.e. inclined against a rod 11 interconnecting the side members 2. The counterbalancing described hereinbelow takes place only when the support member 4 by means of a pull at the handpiece 8 and consequently the hose or cord 9 has been turned upwardly through an angle α to a position immediately before the tube 7 reaches vertical position. In this angular range the support member 4 is not counterbalanced. At a continued pull at the handpiece 8 the support member 4 is swung further through an angular working range β in which the weight of the support member 4 and that of the hose or cord length 9 are completely balanced.
To attain this function the support member 4 and the balancing member 5 in certain cases must permit being released from one another, that is in the angular range of readiness α. This is realized in the manner shown in FIG. 2.
The balancing member 5 which is provided at the lower portion with an adjustable counterweight 12 for counterbalancing the weight of the support member 4 and the hose or cord length 9 is provided in its surface facing the support member 4 with a channel 13 in which a pin 14 protruding laterally from the support member 4 is caused to engage. Upon rotation of the support member 4 in the direction indicated by the arrow 15 from the position of readiness the pin 14 initially moves freely in the channel 13, but at the beginning of the angular working range β it will engage one end 16 of the channel, thereby carrying the balancing member 5 along so that the support member 4 and the hose or cord length 9 are completely counterbalanced.
In the embodiment shown in FIGS. 1 and 2 a balancing member 5 cooperates with two support members 4, which implies that measures must be taken to prevent rotation of one support member from the position of readiness when the other support member is utilized and counterbalanced. This is realized by the channel 13 being extended rearwardly in the direction away from the end 16 so that the pin 14 of the support member which is at rest is not acted upon by the balancing member at the rotation thereof.
Of course, one balancing member 5 could be provided for each supporting member, in which case the channel 13 need not have the rearward extension described in the foregoing. However, for reasons of space and cost it is preferable to have two support members cooperate in the manner shown with one balancing member. It would also be possible to have more than two support members cooperate with one balancing member, but such an arrangement would be complex in structural respect.
In the embodiment illustrated the hose or cord supporting portion of the support member is a tube 7, and the hose 9 extends through said tube 7 and the support member 4. However, other possibilities of running the hose 9 are conceivable as long as the protruding portion of the support member is substantially rigid and counterbalanced in the manner described hereinbefore.
The holder assembly could also be provided with rest means for holding the tools in inoperative position. In the present instance said rest means is a magnet 17 which as shown can be formed as an elongate horse-shoe magnet. In case the tools are not ferromagnetic thin strips or like means of such material may be attached thereto. The advantage of having the rest means for holding the tools in an inoperative position designed as a magnet is on the one hand that the operator can replace the tool on the holder assembly withour raising his eyes from the work he is doing, and on the other hand that the rest means need not be sterile. Should it nevertheless be desired to keep it sterile a thin exchangeable plastic film or the like is readily applicable to the magnet.
Another embodiment of the holder assembly according to the invention is shown in FIG. 3 where the biasing means is a spring instead of a balancing member with a counterweight. In FIG. 3 the parts having their counterpart in the embodiment shown in FIGS. 1 and 2 carry the same reference numerals as in said Figures.
The support member 4 including the tube 7 for receiving a hose or cord is rotatable about the shaft 3 as in the earlier embodiment. In the second embodiment also it is desired to provide a counterbalancing effect in the angular working range β and a return (angle α) by gravity to the position of readiness defined by the rod 11.
The support member 4 is provided with a laterally protruding rib 18 corresponding to the pin 14 and adapted to cooperate with a helical spring 19 which is fixed in relation to the shaft 3 of the holder assembly and has a free end 20. This spring 19 is arranged on a detail (not shown) which may be said to correspond to the balancing member 5 but is fixed in relation to the shaft 3; the spring is secured to a pin 21 on said detail which in turn may constitute the fastening means of the entire holder assembly.
As will appear from FIG. 3, the spring 19 is so dimensioned and mounted as to get in contact with the rib 18 only after the support member has been rotated through an angle α from the position of readiness defined by the rod 11. Within the angular working range β the support member and the weight of the hose or cord disposed thereon are counterbalanced by the coaction between the rib 18 and the end 20 of the spring 19. As the spring end 20 slides against the rib 18 the spring will develop a progressively greater counter-force, which is required for a correct counterbalancing since the weight of the hose or cord will have an ever larger lever arm with respect to the shaft upon outward rotation of the support member 4 with the tube 7 thereof.
Other spring arrangements than that described with reference to FIG. 3 are conceivable as long as they ensure a release within the angular range α and produce a correct counter-force in the angular range β.
All of the advantages associated with a complete counterbalancing of the tool in the entire angular working range thereof, which can be a large one, and also the advantage of the support member returning by gravity to the position of readiness to be held in an inoperative position on positive rest means, in the embodiments illustrated the rod 11, are attained with the aid of the holder assembly according to the present invention.
It is self-explanatory that in addition to those mentioned above many modifications are conceivable within the scope of the invention, and the embodiments illustrated should only be considered as examples. The biasing means illustrated (counterweight and spring) in otherwise conforming design may be replaced by some equivalent biasing means, such as magnet means, pneumatic means or like means. The holder assembly should preferably be provided with an aesthetically pleasing housing.
Of course, it is also possible to use the described holder assembly in connection with tools other than dental tools.