Head-holding Fixture For Use With Visual Instruments

Abstract

A head-holding fixture for use with visual instruments including a frame with a laterally extending bar for engaging the forehead and a moveable chin support for pivoting the head about the laterally extending bar and/or changing the head elevation with respect to it so as to provide both height and tilt adjustment.

Description

This invention relates to head-holding fixtures and more particularly comprises a simple, relatively inexpensive fixture for supporting the head in a fixed position.

Most ophthalmic instruments such as slit lamps, keratometers, visual field plotters, etc. utilize head-holding fixtures of one sort or another. These fixtures have in the past had one or more of the following disadvantages:

A. they required at least two types of adjustment to position the head. Separate adjustments were provided to establish the chin height and the degree of forehead tilt.

B. they incorporated an adjustment system which tilts the head about a fixed chin rest. Because the chin remained relatively stable during such an adjustment, the eyes then moved over a considerable range in spite of the fact that when using instruments which focus on the eyes should remain relatively stable during adjustment.

C. they did not include suitable means for restricting lateral head movement.

D. they were relatively complex and expensive, and required a substantial number of machined parts.

One object of this invention is to provide a head-holding fixture which provides a single adjustment for both head height and tilt.

Another object of this invention is to provide a head-holding fixture with a tilt adjustment which holds the eyes in a relatively stable position.

Yet another object of this invention is to provide a head-holding fixture which has simple means for restricting lateral head movement.

Yet another object of this invention is to provide a head-holding fixture which is composed of few parts, all of which are relatively simple and inexpensive to fabricate.

To accomplish these and other objects, the head-holding fixture of this invention includes a frame having a bar for engaging the forehead. A chin rest is mounted on the frame and is moveable both up and down, and back and forth, so as to pivot, raise, and lower the head with respect to the bar at the forehead. Restraining means are connected to the frame, which engage the sides of the head to resist lateral movement.

In the drawings:

FIG. 1 is a perspective view of a head-holding fixture constructed in accordance with this invention and showing the way it may be associated with an eye movement monitor;

FIG. 2 is a side view of the head-holding fixture as it may be mounted on a table; and

FIG. 3 is a front view of the fixture, both FIGS. 2 and 3 showing the way the head is positioned by it.

In FIG. 1 the head-holding fixture 10 of this invention is shown mounted on the end 12 of an eye movement monitor 14. The eye movement monitor 14 is only exemplary of the type of visual instrument with which the head-holding fixture of this invention may be used, and it is to be understood that in no way limits the scope of this invention. Such head-holding fixtures are often required by scientists, ophthalmologists, optometrists, etc. in either the utilization or examination of a subject's eyes and while in FIG. 1, the fixture is shown secured to the monitor 14, it is to be understood that it may be supported independently of other instruments, and for example, be clamped to a table as shown in FIG. 2. The head-holding fixture of this invention provides a comfortable, simple, reliable, and easily operable device.

The fixture 10 has a base 16 which includes a cylinder 18 having an extendable stem 20 depending from it, which in turn carries a foot 22. The stem 20 may be drawn downwardly from the cylinder 18 so as effectively to raise the entire assembly. A height adjustment knob 24 carrying a pin (not shown) may selectively be positioned in notches (not shown) provided in the stem so as to hold the stem in any selected extended position. A friction arrangement may replace the pin and notches and serve the same purpose. When the fixture 10 is rigidly secured to an instrument, as is the case in the embodiment shown, it is apparent that when the stem 20 is extended the entire assembly is effectively tilted about the legs 25 on end 26 of the machine and end 12 is elevated.

The cylinder 18 supports a generally triangular plate 28 at the top, which in turn carries a tubular frame member 30. The tubular frame member 30 includes a pair of legs 32 and 34 whose lower ends are secured to the rear corners 36 and 38, respectively, of plate 28. The lower portion of the legs 32 and 34 diverge in an upwardly direction so that the vertical sections 40 and 42 are far enough apart so that the head of the subject may fit between them. Generally horizontal forwardly extending arms 44 and 46 are secured to the tops of the vertical sections 40 and 42 and they in turn are joined by a laterally extending horizontal bar 48, which is designed to engage the forehead of the subject about 11/2 inches above the eyes. This is suggested clearly in FIGS. 2 and 3.

A pair of generally vertical plates 50 and 52 are welded or otherwise secured to the bend in the frame member 30 where the vertical sections 40 and 42 join the horizontal forwardly extending arms 44 and 46. These plates serve as the base for clamps 54, which pivotally carry U-shaped bracket 56 which bears the chin rest 58. The clamps 54 are controlled by locking knobs 60; and when the clamps are loosened, the U-shaped bracket 56 may be raised and lowered on the plates 50 and 52, as well as be pivoted on those plates about the axis of the locking knobs 60. To facilitate adjustment of the bracket 56, a handle 62 is provided adjacent the chin support 58, which may readily be grasped by an operator so as to lift and/or pivot the bracket.

A pair of camlike discs 64 are eccentrically mounted on the forwardly extending arms 44 and 46 of the frame member 30 forward of the plates 50 and 52. The discs 64 rotate on the arms 44 and 46 and their peripheries move toward and away from one another depending on their particular angular positions. Because they are eccentrically mounted, it is apparent that rotation does effect the distance between them. The discs are intended lightly to contact the subject's temples to prevent lateral motion of the head when in position within the frame 30.

The operation of the head-holding fixture is as follows: The subject positions his head within the bracket 56 with his forehead resting against the lateral bar 48 so that the center point of the tubing rests about 11/2 inches above the eyes and is centered between them and establishes a tilt axis for the head just above the eyes. The subject is then asked to tilt his head until he is comfortable, and the chin rest is tilted and/or moved up or down to support his chin in that position. The locking knobs 60 are then tightened and the discs 64 are rotated so that they lightly contact the subject's temples and prevent lateral motion of the head. With these easy adjustments the examination or test of the subject's eyes may begin.

While the fixture shown in the drawing is intimately associated with and connected to an eye movement monitor 14, it is to be understood that the fixture is wholly independent of the monitor and may be used with a variety of different devices. Moreover, the cylinder 18 may independently be clamped to a table or other support so that it is not in any way connected to the particular device with which the subject is to be examined or tested.

Claims

What we claim is:

1. A head-holding fixture comprising,

a tubular frame including a laterally extending bar for engaging the forehead,

an adjustable chin rest, means for mounting and adjusting said chin rest on the frame,

said adjusting means including means for providing a single adjustment for both the head height and tilt with respect to the frame,

and restraining means connected to the frame proximate the laterally extending bar for resisting lateral movement of the head in the frame.

2. A head-holding fixture in accordance with claim 1 further characterized by said mounting means including a bracket that carries the chin rest secured on each side of the frame,

said adjusting means including clamps, one on each side of the frame for engaging the bracket,

said adjusting means also including a fastener on each clamp to pivot, raise and lower the bracket on the frame.

3. A head-holding fixture in accordance with claim 1 further characterized by said restraining means comprising a pair of eccentrically mounted discs on each side of the frame for engaging the sides of the head by their edges,

said discs being rotatable to move their edges toward and away from each other.

4. A head-holding fixture in accordance with claim 2 further characterized by said bar for engaging the forehead extending laterally across the frame and establishes a tilt axis for the head just above the eyes,

and said adjusting means enabling the chin rest to move up and down, and back and forth with respect to the laterally extending bar.

5. A head-holding fixture in accordance with claim 4 further characterized by said frame comprising a pair of substantially vertical side posts and a pair of forwardly extending arms attached to the tops of the side posts and joined together by the laterally extending bar,

said discs being mounted for rotation on the forwardly extending arms,

said adjusting means being secured to the frame rearwardly of the discs.