Dental treatment units

Claim 2

A dental treatment unit having an instrument tray and comprising a housing, a support member carried by said housing and having a pivot bearing a dental hand applicance support arm connected at the housing to said support member, said pivot bearing having a vertical axis to permit arcuate movement of said arm relatively to said housing, and a counterbalanced parallelogram arm assembly having a free end carrying the instrument tray and an opposite end mounted on said support member below said support arm, said parallelogram arm assembly being pivotable along with said support arm and comprising a hollow arm.

Claim 3

A dental treatment unit according to claim 1 comprising a pivot bearing with horizontal axis connected to said support member, whereby said support arm is movable upwardly and downwardly relatively to said housing.

Claim 4

A dental treatment unit according to claim 2, wherein said support comprises a casing, said pivot bearing supporting said casing upon said housing and permitting an arcuate movement of said casing relatively to said housing, said appliance support arm and said parallelogram arm being pivotally connected to said casing.

Claim 5

A dental unit as set forth in claim 1, wherein a releasable locking device is provided for securing the arm assembly to the hand appliance support arm, the device being constituted by press stud means on the hollow arm and said support arm.

Claim 6

A dental unit as set forth in claim 3 and further including a dental spittoon unit mounted on the housing, wherein a cam is rigidly secured to the housing beneath the bearing and the support casing, a cam-follower element is secured to an extension of the hollow arm, which extension projects through the bottom of the casing whereby, when the hand appliance support arm is pivoted arcuately over the spittoon unit, the cam element cooperates with the cam to lift the counterbalanced arm assembly above the spittoon unit.

Claim 7

A dental unit as set forth in claim 5, wherein the cam is provided with a nose which projects towards the spittoon unit.

Claim 8

A dental treatment unit housing an instrument tray and comprising a housing, a support member carried by said housing and having a pivot bearing a dental hand appliance support arm connected at the housing to said support member, said pivot bearing having a vertical axis to permit arcuate movement of said arm relatively to said housing, a counter balanced parallelogram arm assembly having a free end carrying the instrument and an opposite end mounted on said support member below said support arm, said parallelogram arm assembly being pivotable along with said support arm and comprising a hollow arm, said hand appliance support arm having the shape of a housing opening toward said arm assembly and enclosing said hollow arm, and a releasable locking device having press stud means on said hollow arm and said appliance support arm and securing said arm assembly to said appliance support arm.

Claim 9

A dental treatment unit housing an instrument tray and comprising a housing, a support member carried by said housing and having a pivot bearing a dental hand appliance support arm connected at the housing to said support member, said pivot bearing having a vertical axis to permit arcuate movement of said arm relatively to said housing, a counter balanced parallelogram arm assembly having a free end carrying the instrument and an opposite end mounted on said support member below said support arm, said parallelogram arm assembly being pivotable along with said support arm and comprising a hollow arm, said hand appliance support arm having the shape of a housing opening toward said arm assembly and enclosing said hollow arm, and a releasable locking device having press stud means on said hollow arm and said appliance support arm and securing said arm assembly to said appliance support arm.