US3189385A - Lock assemblage for adjustable leg rest - Google Patents

Description

June 15, 1965' A. c. MOMMSEN ocx ASSEMBLAGE FOR ADJUSTABLE LEG- REST INVENTOR. ADOLPH C. MOMMSEN 1%.

Fil ed Jap. 6, l964 ATTORNEYS United States Patent 3,189,385 LOCK ASSEMBLAGE FOR ADlUSTAB-LE LEG REST Adolph C. Mornmsen, Minneapolis, Minn, assiguor to Metal-Matic, Inca, lvlinneapolis, Minn a corporation of Minnesota Filed Jan. 6, 19:34 Ser. No. 335,998 Claims. (Cl. 297-429) This invention relates generally to wheel chairs, and pertains more particularly to a lock assemblage or mechanism for maintaining an adjustable leg rest at a desired height with respect thereto.

One object of the invention is to provide a lock assemblage for leg rests that will have extremely smooth operation. In this regard, it is within the contemplation of the invention to permit the leg rest to be easily raised to an appropriate elevation for the user and to afford excellent leverage that permits a ready and controlled lowering of the leg rest to a desired lower position. The invention also has as an aim the locating of the lever or handle in a position that is readily accessible to the occupant of a wheel chair.

Another object of the invention is to provide a shield that is associated with the lock assemblage, the shield mechanism preventing lint and dust from accumulating on the movable parts and thereby creating unsanitary conditions and interfering with the proper gripping action that the assemblage is to provide.

A further object is to provide a lock assemblage of the foregoing character that can be quickly assembled without the need for any special tools or implements.

Still another object of the invention is to provide a lock assemblage for adjustable leg rests that will not become damaged or marred, which damaging or marring would interfere with the proper operation of the assemblage. In this regard, it is an aim of the invention to employ a keeper which coaets with a rod that has a hard surface, the keeper being formed of a material no harder than that of the rod. In this way, the keeper, which is cocked or tilted to maintain the rod in a locked condition, does not score or mutilate the rod in any way and the continued smooth surface of the rod obviates any chance of the adjustment becoming jerky or irregular after a prolonged period of use.

These and other objects and advantages of my invention will more fully appear from the following description, made in connection with the accompanying drawing, wherein like reference characters refer to the same or similar parts throughout the several views and in which:

FIGURE 1 is a perspective view showing a wheel chair equipped with a lock assemblage constructed in accordance with the teachings of the present invention;

FIGURE 2 is a side elevational view of the leg rest as it appears in FIGURE 1, although a raised position of the leg rest has been shown in phantom outline;

FIGURE 3 is a fragmentary detail of the lock assemblage with portions thereof broken away in order to illustrate to better advantage the manner in which the locking or gripping action is performed, and

FIGURE 4 is a sectional view taken in the direction of line 44 of FIGURE 3.

Although the invention may be used with a variety of wheel chair constructions, a typical wheel chair has been denoted in its entirety by the reference numeral ill. The wheel chair that has been selected for illustrating the invention includes a folding frame 12 having an upper horizontal tubular member 14 at each side, a lower horizontal tubular member 16 at each side, and vertical legs 18 extending between these tubular members 14, 16.

Before describing the adjustable leg rest with which my lock assemblage is used, it will be of advantage as far as background material is concerned to describe briefly a non-adjustable leg rest which has been indicated gen erally by the reference numeral 20. The leg rest 20 comprises an inclined member 22 having a horizontal upper end 24 that is received in the tubular member 14 at the left of the wheel chair 1%. Intermediate the ends of the inclined member 22 is a branch tube 26 that is received in the left lower tubular member 16. An L-shaped tubular member 23 is attached to the lower end of the inclined member 22 through the agency of a U clamp 30. A bolt 32 produces the requisite clamping action. In this way, a foot support 34 is retained at a fixed elevation with respect to the wheel chair Ill and its frame 12.

An adjustable leg rest has been designated generally by the reference numeral 36 and comprises an inverted L-shaped member 38 having an upper horizontal projection 40. The adjustable leg rest 36 is intended to be detachable and as can be discerned from FIGURE 2, there is a U-shaped spring 42 contained in the projection 40 that urges a detent 44 downwardly with respect to a hole 46 formed in the right upper horizontal tubular member 14. In addition to the upper horizontal projection 4d of the L-shaped member 33, there is a vertical portion labelled 48. At the lower end of the vertical portion 48 is a horizontal projection 49' that is received in the lower horizontal tubular member 16. The upper horizontal projection 41) on the L-shaped member 38 has a bifurcated end 50 through which extends a pivot pin or bolt 52. I

The pin or bolt 52 serves as a pivot for an obtuse arm 54 having an elbow designated by the numeral 56 that is selectively positionable in a manner presently to be described. The leg rest generally denoted by the reference numeral 36 also includes a calf support 53. At the lower end of the obtuse arm 54 is an L-shaped tube as having a U clamp 62 and bolt 64 for the purpose of attaching same to the arm 5- The lock assemblage for maintaining the leg rest 36 at any desired elevation will now be described. The assemblage includes an L-shaped rod 63 having a relatively hard surface. The reason for the hard surface will become clear as the description progresses. In this regard, though, it is contemplated that the rod 68, as are other parts that have been described and which will hereinafter be referred to, may be plated with chromium or otherwise hardened. Chrome plating naturally presents a relatively hard surface, but with respect to the rod 68 such surface may also conveniently have a zinc coating thereon which assists in producing a high degree of gripping action which will be explained hereinafter. The L-shaped construction of the rod 68 presents a relatively short leg 70 and a relatively long leg 72. Aligned apertures 74 in the elbow 56 of the obtuse arm 54! permits the short leg '76 of the rod as to be pivotally attached to said arm 54. While the rod 6% is pivotally connected to the arm 54 at one end, the other end thereof has a stop in the form of a split washer '76 that resides in a circumferential groove formed at the end of the relatively long leg '72.

At this time, attention is called to the use of an L- shaped member 78 providing a vertical flange 80 and a horizontal flange 84, the horizontal flange 84 having a transverse slot 36 formed therein. The vertical flange 80 of the member 78 is affixed, as by soldering or brazing, to a sleeve or tubular bearing $2 which encircles the relatively long leg '72 of the Lshaped rod 68.

The lock assemblage further includes a release lever 96 having a straight shank portion Ell with a cap 94 at the upper end thereof so as to provide a convenient operating handle for the lock assemblage. The release lever 9 9t? has a U-shaped portion 96 that provides an upper horizontal or transverse leg 98, a curved bight segment 1100, and a lower horizontal or transverse leg 162. The horizontal leg MP2 is journalled in a tubular bearing 88 that is secured, as by brazing or soldering, to the vertical portion 48 and has a stop in the form of a split washer TAM for preventing the free end of the leg Hi2 from being inadvertently withdrawn from the bearing 88, the washer being identical to the one labelled '76 that has already been referred to. The groove for anchoring the washer 104 has been assigned the reference numeral 1% and the presence of the groove can best be understood from FIGURE 4.

Fixedly carried by the release lever 96, more specifically the lower horizontal leg 162 thereof, is a keeper 198 in the form of an ear or tongue that is attached to the lever 90 by brazing or soldering. In other words, the keeper llltl is integral with the lever 90 and will be rocked when the lever is actuated, the previously-mentioned tubular bearing 88 serving as a pivot for such rocking action. The keeper 1% is, however, located at the opposite end of the bearing 83 from the washer EM and therefore assists in preventing unwanted lateral shifting of the lever 90. The keeper ltlS extends downwardly through the transverse slot St; in the horizontal flange of the mem ber 78 and the lever 9-9 is thus additionally constrained from lateral movement. By virtue of an oversized aperture 110 formed in the keeper N8, the keeper is permitted to loosely encircle a portion of the Lshaped rod 68, more specifically the long leg 72 thereof. Whereas the leg 72 is chromium plated, the wall of the aperture lltl is not, thereby presenting only a mild steel surface that will not damage the rod 68 when gripping the leg 72. A coil spring 112 interposed between the vertical flange (ill of the member '78 and the keeper 1% is instrumental in normallyurging the keeper 1th into a cocked or tilted relationship with respect to the rod 63.

Having presented the foregoing information, the mannet in which my lock assemblage is used for the purpose of maintaining the leg rest 36 at any desired angular position should be readily understood, From FIGURE 3, it can be appreciated that the cocked position of the keeper M8 is responsible for gripping the long leg 72 of the L- shaped rod 63 so that the rod is prevented from moving to the right or toward the vertical portion 48 of the inverted L-shaped member 33. The binding or gripping action due to the tilted position of the keeper 1% produces a force that is immediately transmitted via the tubular bearing 88 to the vertical portion 48 of the inverted L- shaped member 33. Thus, the obtuse arm 5'4 is retained at any selected angular position due to the clamping action provided by the keeper 1%. Stated somewhat differently, even if the leg rest 36 is at a high position, such as that shown in phantom outline in FIGURE 2, there can be no downward movement and the weight of a persons leg will be supported on the member 53 and the leg will be kept at the elevation shown.

On the other hand, if the user desires to lower the leg rest 36, he can conveniently and quickly do so by pull ing the release lever 90 toward him, that is, moving the lever 94) in a clockwise direction as shown in FIGURES l3. When the lever 90 is so manipulated, then the keeper 1% is moved into a more nearly perpendicular relationship with the long leg 72 of the rod 68. Due to the clearance provided by the aperture 114), it can be seen that the more nearly perpendicular relationship permits the leg '72 to slide relative tothe keeper res. Once the user relaxes his pull on the lever W, though, the coil spring 112 immediately biases the keeper 1% back into the position in which it appears in FIGURE 3. In other words, the gripping action due to the cocking or tilting of the keeper 108 is immediately re-established when the user releases his grasp on the lever 98. it will be under stood that the user has a very accurate control of the lock assemblage and can pivot or rock the lever as in 4 small angular increments that permit the leg rest 36 to be lowered to just the right height that is desired.

The hard surface of the rod 68 does not become marred or notched by the keeper and hence remains smooth and easily controlled. Additionally, where a zinc overcoating is used, a positive friction grip may be main tained, even under high forces. However, since the zinc overcoating is very thin, the hard undersurface still prevents marring of the rod. Because the flange 86 on the member 78 overlies the relatively long leg '72 of the rod lint and dirt do not tend to collect on the rod and spring but will merely lie on the top surface of the flange from which it can easily be wiped oil.

It will, of course, be understood that various changes may be made in the form, details, arrangements and proportions of the parts without departing from the scope of my invention as set forth in the appended claims.

What is claimed:

1. in combination with an adjustable leg rest for wheel chairs including a generally vertical first member, a second member pivotally connectet. at its upper end to said first member, and means carried on said second member for supporting a persons leg, a lock assemblage for said leg rest comprising:

(a) a generally horizontal rod pivotally connected at one end to said second member at a point beneath the pivotal connection of said first and second member;

(b) a lever having a horizontal U-s'naped portion connected to the first member of said leg rest;

(0) a keeper atlixed to the lower leg of said lever having an aperture therein through which said rod freely extends;

(d) a sleeve encircling said rod so as to permit slidable movement of said rod with respect thereto;

(e) a vertical flange affixcd to one end of said sleeve;

(f) a horizontal flange athxed to the upper end of said vertical flange and overlying a portion of said rod and havin a transverse slot therein through which said keeper projects; and

(g) a coil spring interposed between said keeper and said sleeve in an encircling relation with said rod for normally cocking said keeper into a tilted position with respect to said rod so as to cause gripping there of to thereby prevent movement of said rod and second member toward said first member,

(h) whereby actuation of said lever into a position to cause said keeper to assume a more nearly perpendicular relationship with said rod will allow said rod and second member to move toward said first member.

2. In combination with an adjustable leg rest for wheel chairs including a generally vertical first member, a second member pivotally connected at its upper end to said first member, and means carried on said second member for supporting a persons leg, a lock assemblage for said leg rest comprising:

(a) a generally horizontal rod pivotally connected at one end to said second member at a point beneath the pivotal connection of said first and second member;

(b) a lever having a U-shaped portion providing upper and lower horizontal legs and a connecting bight;

(c) bearing means on said first member for pivotally supporting the lower leg of said lever;

(d) an upstanding shank portion connected to the free end of the upper leg of said lever for actuating said lever;

(e) a keeper aflixed to the lower leg of said lever between said bearlng means and the bight portion thereof, said keeper having an a; erture therein through which said rod freely extends;

(f) a sleeve encircling said rod so as to permit slidable movement of said rod with respect thereto;

(g) a horizontal flange carried by said sleeve in an overlying relationship with a section of said rod and having a transverse slot therein through which said keeper projects, and

(h) a coil spring interposed between said keeper and said sleeve in an encircling relationship with said rod for normally cocking said keeper into a tilted position with respect to said rod so as to cause gripping thereof to thereby prevent movement of said rod and second member toward said first member,

(i) whereby actuation of said lever via said shank portion into a position to cause said keeper to assume a more nearly perpendicular relationship with said rod will allow said rod and second member to move toward said first member.

3. The combination of claim 2 in which:

(a) said rod has a hard and smooth surface, and

(b) the wall of said keeper aperture has a surface n0 harder than the surface of said rod.

4. The combination of claim 2 including:

(a) a washer element carried at the free end of said lower leg for preventing removal of said lower leg from said bearing means, and

(b) said keeper residing adjacent the other end of said bearing means.

5. In combination with an adjustable leg rest for wheel chairs including a generally vertical first member, a second member pivotally connected at its upper end to said first member, and means carried on said second member for supporting a persons leg, a lock assemblage for said leg rest comprising:

(a) a generally horizontal rod pivotally connected at one end to said second member at a point beneath the pivotal connection of said first and second member;

(b) a lever pivotally connected to the first member of said leg rest;

(0) a keeper atlixed to said lever having an aperture therein through which said rod freely extends;

(d) a sleeve encircling said rod so as to permit slidable movement of said rod with respect thereto;

(e) a flange aifixed to said sleeve and projecting there-' from in an overlying parallel relationship with a portion of said rod and having a transverse slot therein through which said keeper projects, and

(f) a coil spring interposed between said keeper and said sleeve in an encircling relation with said rod for normally cocking said keeper into a tilted position with respect to said rod so as to cause gripping thereof to thereby prevent movement of said rod and second member toward said first member,

(g) whereby actuating of said lever into a position to cause said keeper to assume a more nearly perpendicular relationship with said rod will allow said rod and second member to move toward said first member.

References Cited by the Examiner UNITED STATES PATENTS 2,520,309 8/50 Everest et a1 297433 2,793,682 5/57 Duke 297--433 2,833,081 5/58 Pottern 108-9 2,924,299 2/60 Kanzelberger et al 188-67 3,021,889 2/62 Mize 297-429 FRANK B. SHERRY, Primary Examiner.

Claims (1)

1. IN COMBINATION WITH AN ADJUSTABLE LEG REST FOR WHEEL CHAIRS INCLUDING A GENERALLY VERTICAL FIRST MEMBER, A SECOND MEMBER PIVOTALLY CONNECTED AT ITS UPPER END TO SAID FIRST MEMBER, AND MEANS CARRIED ON SAID SECOND MEMBER FOR SUPPORTING A PERSON''S LEG, A LOCK ASSEMBLAGE FOR SAID LEG REST COMPRISING, (A) A GENERALLY HORIZONTAL ROD PIVOTALLY CONNECTED AT ONE END TO SAID SECOND MEMBER AT A POINT BENEATH THE PIVOTAL CONNECTION OF SAID FIRST AND SECOND MEMBER; (B) A LEVER HAVING A HORIZONTAL U-SHAPED PORTION CONNECTED TO THE FIRST MEMBER OF SAID LEG REST; (C) A KEEPER AFFIXED TO THE LOWER LEG OF SAID LEVER HAVING AN APERTURE THEREIN THROUGH WHICH SAID ROD FREELY EXTENDS; (D) A SLEEVE ENCIRCLING SAID ROD SO AS TO PERMIT SLIDABLE MOVEMENT OF SAID ROD WITH RESPECT THERETO; (E) A VERTICAL FLANGE AFFIXED TO ONE END OF SAID SLEEVE; (F) A HORIZONTAL FLANGE AFFIXED TO THE UPPER END OF SAID VERTICAL FLANGE AND OVERLYING A PORTION OF SAID ROD AND HAVING A TRANSVERSE SLOT THEREIN THROUGH WHICH SAID KEEPER PROJECTS; AND (G) A COIL SPRING INTERPOSED BETWEEN SAID KEEPER AND SAID SLEEVE IN AN ENCIRCLING RELATION WITH SAID ROD FOR NORMALLY COCKING SAID KEEPER INTO A TILTED POSITION WITH RESPECT TO SAID ROD SO AS TO CAUSE GRIPPING THEREOF TO THEREBY PREVENT MOVEMENT OF SAID ROD AND SECOND MEMBER TOWARD SAID FIRST MEMBER, (H) WHEREBY ACTUATION OF SAID LEVER INTO A POSITION TO CAUSE SAID KEEPER TO ASSUME A MORE NEARLY PERPENDICULAR RELATIONSHIP WITH SAID ROD WILL ALLOW SAID ROD AND SECOND MEMBER TO MOVE TOWARD SAID FIRST MEMBER.

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