Weighing Scale

This scale is an improvement on the scale illustrated in Swersey et al, U.S. Pat. No. 3,530,949, dated Sept. 29, 1970.

The scale of this invention is constructed to facilitate movement of a wheeled load, such as a bed, on and off the scale. It is also constructed to change quickly between a rolling condition in which it may be moved from one location to another and a weighing condition in which it is stationary on the floor. The scale is provided with four casters, two at each end. The frame rests on the floor when the scale is in the weighing condition, and may be lifted from the floor onto the casters by a pair of linkages, one at each end, which are manually operable by a detachable handle.

The scale has an oblong frame with two short sides and two long sides. A bed being weighed is supported on a pair of upwardly open, channel-shaped rails, which extend across the short sides of the frame. Retractable blocking bars are provided at each end of each rail. In their blocking positions, these bars prevent the bed from accidentally rolling off the scale. When retracted, the bars allow the bed to roll off the open ends of the rails. Removable ramps are provided for loading a bed onto the rails. The ramps are also upwardly open, channel-shaped members, and are removable so that they may be used on either side of the scale, or loaded on the scale for transportation.

FIG. 1 is a plan view of a scale embodying the invention.

FIG. 2 is a front elevational view of the scale of FIG. 1, showing the scale frame resting on the floor in its weighing position.

FIG. 3 is a right end view of the scale shown in FIG. 2, again showing the scale in its weighing position.

FIG. 4 is a view similar to FIG. 3, showing the scale in its traveling position.

FIG. 5 is a fragmentary sectional view taken on the line 5--5 of FIG. 4.

FIG. 6 is a sectional view taken on the line 6--6 in FIG. 3.

FIG. 7 is a sectional view taken on the line 7--7 in FIG. 4.

FIG. 8 is an exploded perspective view showing a ramp supporting mechanism and a rail blocking bar.

This scale comprises a base frame in the form of a hollow rectangle with two long side members 1a and two short side members 1b. The side members 1a and 1b are peferably angle irons, as best seen in FIGS. 6 and 7. In each corner of the base 1 is mounted a hydraulic load cell 2, all connected by conduits 3 to a balance mechanism 4, which is in turn connected to an indicator and control assembly 8, shown only diagrammatically, and which may be the same as that illustrated in U.S. Pat. No. 3,530,949, mentioned above.

Mounted on the load cells 2 is a secondary frame comprising two elongated side rails 5a and two shorter end rails 5b. The end rails are of channel-shaped cross-section, with the open side of the channel facing upwardly so as to receive and guide the wheels on a wheeled load, such as a bed.

At each end of each rail 5b, a pair of wings 6 (best seen in FIG. 8) are welded to its outer sides. A straight cylindrical pin 7 projects upwardly from the left-hand wing 6, as viewed in FIG. 8, and is receivable in an aperture 10a in a retractable blocking bar 10. Another pin 9 having a head 9a projects upwardly from the right-hand wing 6, and extends through another aperture 10b in the bar 10, with the head 9a above the bar to limit the upward movement thereof. The bar may be moved from the retracted position, shown in full lines in FIG. 8, to a blocking position, shown in dotted lines. This movement is accomplished by pivoting the bar 10 on the pin 9, and lifting it as required to engage or disengage it from the pin 7. When the bar 10 is in its blocking position at the end of the rail 5b, a bed resting in the rail cannot accidentally roll off the end of the rail. When the bar is retracted, the bed can freely roll off the rail.

A bed or other wheeled load may be moved on or off the rails 5b by placing a pair of ramps 11 in the position illustrated in FIG. 3, and at the lower right in FIG. 1. Each ramp 11 has a channel-shaped cross-section, and has its open side facing upwardly.

Welded to the underside of each rail 5b adjacent each end thereof is a crossbar 12. A pair of arms 13 are welded on the outside of the one end of each ramp 11. The arms 13 are provided with recesses 13a in their bottom surfaces, which are adapted to rest on the projecting ends of the crossbar 12, as shown in FIG. 3. When the ramps are in place, as shown in FIG. 3, a bed can be readily rolled up to ramps 11 onto the rails 5a to be supported by the scale. The blocking bars 10 may then be put in place, thereby securing the bed in position on the scale.

During the weighing, the ramps 11 must be removed from the positions just described. During transportation of the scale, and during weighing, the ramps may be mounted in storage positions on the rail 5a, as shown in the case of the left ramp 11 in FIGS. 1 and 2. Studs 41 (FIG. 1) extend upwardly from the rail 5a and may be received in holes 11a in the ramps 11. Wing nuts 42 (FIG. 1) on the studs hold the ramps 11 in position on the rail 5a. The arms 13 then embrace the sides of the rail 5a, and assist in holding the ramps in place.

When it is desired to move the scale from one location to another, the base 1 is lifted off the floor and its weight transferred to four casters 16 by the mechanism as illustrated in FIGS. 3, 4, 6 and 7. Adjacent each end of each of the short base frame members 1b, near its upper edge, there is provided a box-like extension 14 having upper and lower walls 14a and 14b (FIGS. 6 and 7) which are apertured to receive slidably a sleeve 15. A caster 16 of conventional form has its spindle 16a rotatably received in each sleeve 15 and held against outward movement from that sleeve. Welded to the lower end of each sleeve 15 is a projection 17 on which is pivoted a link 18. The upper end of each link 21 is, in turn, pivoted to a plate 19 welded on the upper end of the extension 14. Each set of links 18, 21 constitutes an over-center linkage. A transverse link 22 extends between the common pivots of the links 18 and 21 at the ends of the short base frame member 1b. The link 21 appearing at the left in FIG. 3 is provided with a fixed extension 21a. A similar fixed extension 18a is provided on the link 18 at the right end side of FIG. 3. A handle 23 (FIG. 1) is carried in a pair of spring clips 24 fixed to the top of the balance mechanism 4, and may be removed from those clips. A socket on the end of the handle 23 fits either the projection 21a or the projection 18a. When the handle 23 is connected to either of those projections, it may be employed to swing the linkages 18, 21 and 22 over center from the position shown in FIG. 3 to the position shown in FIG. 4, or vice versa. A stop pin 25 limits the motion of the over-center linkage in the direction shown in FIG. 4. When the parts are in that position, the casters 16 engage the floor and the base frame member 1b is lifted from the floor. When the parts are in the position shown in FIG. 3, the casters 16 may have their wheels resting against the floor, but the base frame member 1b is supported directly by the floor and not by the linkages 18, 21 and the casters.

The projection 18a is on the lower link 18 at the right side as viewed in FIGS. 3 and 4, and the projection 21a is on the upper link 21 at the left side. Hence, when the handle 23 is operated from either side of the scale, an upward movement of the handle lowers the base onto the floor, and a downward movement of the handle raises the base from the floor onto the casters 16. That is to say, operation of handle 23 in a given sense on either side of the base provides the same motion of the sleeve. See the arrows in FIGS. 3 and 4.

During the movement of the mechanism from the position shown in FIG. 3 to the position shown in FIG. 4, or vice versa, the rail 5b at that end of the scale is mounted parallel with the ground at all times. Hence, if it is desired to move the scale while a bed and a patient are supported on it, there is no tendency to tilt the bed in a direction to unload it from the scale, by virtue of the operation of this jacking mechanism.

A drawbar 26 is supported on the top of the balance mechanism 4 when not in active use. The drawbar is held in that position by clips 28. One end of the drawbar 26 is connected by a pivot pin 33 to a channel-shaped coupler 34 (FIGS. 1, 2 and 5) slotted at 34a.

A mating coupler 27 is mounted on the base frame 1b. The coupler 27 includes a yoke 30 having its ends welded to the base frame 1b and a bolt 31 extending through an opening in the yoke 30 and having its inner end welded to the frame 1b. A manually rotatable knob 35 is threaded on the bolt 31. A bolt head 31a and a washer 36 limit the movement of the knob away from the yoke 30.

When it is desired to pull the scale along the floor on its casters, the drawbar 26 is removed from the clips 28 and the flange 34 is inserted between the yoke 30 and the frame 1b, with the bolt 31 entering the slot 34a. The knob 35 is then tightened to maintain the drawbar in place, after which the scale may be readily pulled along the floor by means of the drawbar.