Adjustment apparatus for stirrup assembly including rotating clamp bracket

[57] ABSTRACT

A mechanism is disclosed for permitting vertical and angular adjustment of a stirrup assembly located at either side of the foot end of a medical examination table. The assembly includes a clamping bracket pivotally secured to a horizontally extending extension bar. When the bracket is in a lowered position, it clamps the stirrup support rod and fixes the position of the stirrup assembly. When the bracket is raised, either by raising the bracket itself or by pulling the stirrup assembly, the stirrup support rod is released and the stirrup assembly may be adjusted.

Claims, 7 Drawing Figures

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PATENTED» 16 BM

3.823.933

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3,823,933

ADJUSTMENT APPARATUS FOR STIRRUP ASSEMBLY INCLUDING ROTATING CLAMP BRACKET

BACKGROUND AND SUMMARY

The present invention relates to a mechanism for adjusting the stirrup assembly such as are found at either side of the foot end of a medical examination table. Typically, each stirrup assembly is secured to a horizontally extensible support bar which is received in the 10 table and adjustable by loosening and tightening a hand wheel.

The stirrup assembly is located at the end of the extensible support bar, and the stirrup itself is supported on a rod which is clamped to the extensible stirrup sup- ¹⁵port bar by means of a second hand wheel assembly. Thus, prior mechanisms for adjusting stirrup assemblies vertically and angularly have heretofore required the use of two hands, one for turning the hand wheel and the other for holding and adjusting the stirrup assembly. This is inconvenient for the treating physician. Further, it normally requires considerable force to securely clamp a stirrup assembly with a hand wheel, and it will be realized that for treatment or examination, the stir- _ rup assemblies must be firmly and rigidly clamped so as ²⁵not to come loose and possibly cause the patient to lose balance.

The present invention includes apparatus for clamping a stirrup support rod while permitting adjustment. ₃₀Both the clamping and adjusting operations require only a single hand to accomplish.

In the present invention, a U-shaped bracket is mounted to a horizontal extension bar for pivotal motion about a horizontal axis between a raised and a low- 35 ered position. In the lowered position, the bracket extends beyond the distal edge of the extension bar and cooperates with it to provide a receptacle for the stirrup support rod, clamping it in place.

In one embodiment, a resilient, compressible brake 40 pad is secured to either the extension bar or the bracket to engage the rod and clamp it rigidly when the bracket is lowered after the rod has been adjusted. In another embodiment, a dowel pin is fitted into the end of the extension bar and adapted to engage and secure the rod 45 when it is lowered.

When the bracket is raised, either by grasping the bracket itself or by pulling the clamped rod upwardly, it brakes into an unlocked position, releasing the clamping pressure on the rod and thereby permitting ⁵⁰adjustment of the stirrup assembly. Thus, with the present invention, a stirrup assembly can be adjusted in elevation or angular disposition quite easily and with the motion of a single hand. Further, the present invention offers greater reliability in clamping the stirrup assem- ⁵⁵bly in the locked position than has heretofore been realized with the prior hand wheel assemblies because in the present invention, when weight is applied to the stirrup assembly, it tends to force the bracket as well as the stirrup rod downwardly and because of the shape ⁶⁰of the receptable, this induces an even tighter clamping force on the rod.

Other features and advantages of the present invention, including better appearance and lower manufacturing costs, will be apparent to persons skilled in the ⁶art from the following detailed description of a preferred embodiment accompanied by the attached drawing wherein identical reference numerals will refer to like parts in the various views.

THE DRAWING

FIG. 1 is a fragmentary upper perspective view taken from the foot end of a medical examination table incorporating the present invention;

FIGS. 2 and 3 are fragmentary top and side views respectively of an improved mechanism for vertically adjusting a stirrup assembly;

FIGS. 4 and 5 are fragmentary top and side views of a modified stirrup adjustment mechanism respectively;

FIG. 6 is a fragmentary side view similar to FIG. 3 showing the unlocking of the adjustment mechanism; and

FIG. 7 is a fragmentary cross sectional side view of still another embodiment of the invention.

DETAILED DESCRIPTION

Referring first to FIG. 1, reference numeral 10 generally designates a medical examination table including first and second adjustable stirrup assemblies 11. Each of the stirrup assemblies 11 is similar in structure and operation but designed to accommodate either a left or a right foot. Hence, only one of the stirrup assemblies need be described in detail for a full appreciation of the invention.

Each stirrup assembly includes a stirrup 12 secured by a support rod including an upper inclined portion 13 and a lower vertical portion 14. Each of the stirrup assemblies 11 is adjustable in a horizontal direction away from the foot of the table 10 by means of an extensible horizontal bar 15 secured by a conventional hand wheel 16. The mechanism for horizontal adjustment forms no part of the present invention, and will not be further discussed.

Turning now to FIGS. 2 and 3, it will be observed that the extension bar 15 is rectangular in cross section, having a greater depth than width. The distal edge of the extension bar 15 is designated by reference numeral 17, and as best seen in FIG. 3, the upper corner 18 is rounded to form a smooth transition between the top 19 and the distal edge 17. Turning now to FIG. 2, a bracket 20 having a generally U-shape includes a curved portion 21 and first and second arms 22, 23. The bracket 20 is pivotally mounted to the extension bar 15 by means of a pin 25 for rotation about a horizontal axis. First and second spacer members 26 and 27 are welded to the inner sides of the arms 22,23 respectively to fill the space that would otherwise exist between these arms and the sides of the extension bar 15. It will be observed that the curved portion 21 of the bracket 20 is designed to wrap about the periphery of the vertical portion 14 of the stirrup support rod which has a diameter greater than the thickness of the extension bar 15.

A pad designated 30 and formed of resilient, compressible material is secured to the inner surface of the curved portion 21 of the bracket 20 so as to engage the outer periphery of the vertical portion 14 of the stirrup support rod. The material for the compressible pad 30 may be neoprene, and it is secured to the bracket 20 by any suitable bonding agent such as contact adhesive.

It will be observed from FIGS. 2 and 3 that the curved portion 21 of the locking bracket 20 cooperates with the distal edge 17 of the extension bar 15 to pro3,823,933 vide a socket or receptacle for receiving the support rod 14 and clamping it against rotational movement and against further downward movement. Rather, a downward force on the stirrup support rod will urge the bracket further downwardly, and because of the frictional force between the rod 14 and the pad 30, the lower edge 32 of the curved portion 21 of the locking bracket 20 will be urged inwardly against the rod, thereby increasing the clamping pressure. This action is enhanced because the lower outer corner 33 of the extension rod 15 is squared, as illustrated in FIG: 3.

In order to release the clamp so as to adjust the height or angular disposition of the rod 14, the Idshaped clamping bracket 22 is pulled upwardly, as seen in FIG. 6, thereby disengaging the rod from the outer bearing surface 17 of the extension bar 15. It will be observed that the clamping bracket 20 may be thus raised and lowered between the release and the locking positions either by grasping the bracket itself or by urging any portion of the stirrup assembly 11 due to the frictional contact between the pad 30 and the outer periphery of the stirrup support rod.

A modification of the mechanism just described is illustrated in FIGS. 4 and 5; however, the operation just described is identical for the modified structure. Turning then to FIGS. 4 and 5, reference numeral 15 again designates the horizontal extension bar, 17 designates the outer distal edge of the bar 15 which, in this embodiment does not form a bearing surface but, rather, is displaced slightly inwardly from the rod 14 even in the locked position shown in FIG. 5. Again, the upper outer edge of the extension bar is curved as at 18.

The clamping bracket 20, the spacers 26,27 and the attachment of the bracket 20 to the bar 15 are also similar to that which has already been described. In this embodiment, however, the lower outer edge of the extension bar 15 is notched at 40 in the form of a transverse channel, and a pad 41 of resilient, compressible material is attached to the bar 15 to fill the notch 40. The pad 41 extends slightly beyond the distal edge 17 of the extension bar 15. In this embodiment, the inner surface of the curved portion 21 of the clamping bracket 20 directly engages the rod 14.

Turning now to the modification illustrated in FIG. 7, reference numeral 15 again designates the horizontal extension bar, 17 designates the outer distal edge of the bar 15, and 18 designates the upper curved portion of the extension bar 15. This embodiment also includes a U-shaped clamping bracket 20, provided with a curved portion 21, and spacers similar to the above-described embodiments.

In this embodiment, a dowel pin 45 is fitted into an aperture 46 formed in the extension bar 15. The center of the dowel pin 45 is adjacent the distal edge 17 of the extension bar 15, and the axis of the dowel pin 45 is parallel to the axis of rotation of the clamp bracket 20—that is, it is transverse to the axis of the support rod 14 for the stirrup assembly.

The dowel pin 45 is further located so as to project slightly outwardly of the flat edge 17 of the extension bar 15 to engage the rod 14 when the bracket 20 is in its clamping position. In other words, the rod 14 is clamped between the curved portion 21 of the bracket 20 and the exposed surface of the dowel pin 45. The stirrup rod may be adjusted to its desired height with one hand. As the stirrup rod is moved to a vertical, clamped position, the rod 14 pivots on the exposed sur face of the dowel pin 45, causing the rod to be clamped between the bracket 20 and the pin 45. Although it is not shown, a resilient pad may be used in conjunction with the pin 45, similar to that which is shown in the embodiment of FIGS. 2 and 3, although it is not necessary. Further, the illustration shows a solid dowel pin 45, but a spring steel roll pin may equally well be used, and in this latter case, the rod would slightly compress the roll pin, aiding the locking action.

It will be observed that the location of the pivot pin 25 of the embodiments of FIGS. 4 and 5 is raised relative to the previous embodiment, compare FIGS. 3 and 5. In the embodiment of FIG. 3, the location of the pivot pin 25 may vary with the thickness and location of the pad 30. However, it will be appreciated that in both embodiments when the U-shaped bracket clamps the stirrup support rod in the lowered position, any further downward force tends to enhance the clamping pressure; yet the clamping pressure is easily and totally released when the rod or bracket is urged upwardly and pivoted, as already described.

The present invention thus provides an economical mechanism for clamping a stirrup support rod while permitting both vertical and angular adjustment of the stirrup assembling requiring the use of only one hand on the part of the person effecting the adjustment. When the mechanism is locked, the normal downward force encountered in use serves to strengthen the clamping action so that the mechanism of the present invention is more reliable than those currently being employed.