US 2784585 A
Description (OCR text may contain errors)
w. KAUFFMAN u 2,784,585
WRINGERS March 12, 1957 3 Sheets-Sheet 1 Filed March 21, 1952 I I I l l T l l \l Inventor Mafch 12, 1957 W. L. KAUF 'FMAN ll WRINGERS Filed March 21. 1952 3 Sheets-Sheet 2 Zinoentor March 12, 1957 w, KAUFFMAN 11 2,784,585
WRINGERS 3 Sheets-Sheet 3 Filed March 21, 1952 Unite rates atent WRINGERS Walter L. Kaufiman II, Erie, Pa., assignor t Lovell Manufacturing Company, Erie, Pa., a corporation of Pennsylvania Application March 21, 1952, Serial No. 277,778
8 Claims. (Cl. 68-456) This is a continuation in part of application Serial No. 569,770, filed December 26, 1944, now Patent No. 2,592,575, April 15, 1952.
This invention is intended to improve the wringing characteristics of clothes wringers by having one of the rolls hinged to swing toward the other roll under spring pressure. With such arrangement, the hinged roll is kept from tilting and the wringing at any point along the length of the rolls is due to the compression of the rubber plus the spring pressure, the sum of which can be made essentially constant in its wringing effect or to have any desired variation.
In the drawing, Fig. 1 is a front elevation of a wringer; Figs. 2 and 3 are sectional views, on lines 2-2 and 3-3 of Fig. 1; Figs. 4 and 5 are modifications of the rolls; Fig. 6 is a front elevation of a modification using a leaf spring; Fig. 7 is a front elevation of another modification using a leaf spring; Fig. 8 is a front elevation of a modification using trapped coil springs; and Fig. 9 is a fragmentary view showing one of the trapped coil springs.
In Fig. 1, the wringer has a head 106 housing the reversing mechanism controlled by a handle 107 and having a depending sleeve 103 for mounting on the wringer post. Fixed to the wringer head is a frame comprising a bottom frame member 109 and side stiles 110, 111 for slidably receiving bearing blocks for shafts 112a and 113a of upper and lower rolls 112 and 113. The bearing blocks 114 for the lower rolls are rigidly carried on seats 115 on the bottom frame member 109. The bearing blocks 11s for the upper roll are pivoted at 117 on carriers 117a positioned by adjusting screws 11712 on a top bar 118 hinged at 119 on the wringer head for swinging movement toward and away from the lower frame. Since the wringer head and frame member 109 are fixed together, the wringer head and frame member 109 together comprise the bottom frame of the wringer.
The roll pressure mechanism comprises a toggle link 120 pivoted at 121 on the top bar and a toggle link 122 pivoted at 123 on the side stile 111 and having a pin 124 slidably received in slots 125 in the spaced side walls 126 of the toggle link 120. The pin 124 is yieldably held against the upper end of the slots 125 by a compression spring 127 trapped between a seat 124a on the pin 124 and a seat 128a on the bottom wall 128 of the toggle link 120. The pin 124 is at all times outside of a center line connecting the pivots 121 and 123 so the spring 127 urges the toggle links toward the released position. The toggle links are held. in set position by a latch 129 on a pivoted release bar 130 which cooperates with a hook 131 on the toggle link 122. By pushing the release bar, the latch 129 is swung clear of the hook 131 releasing the toggle. The latch 129 and hook 131 are or may be of common construction. The toggle has pressure characteristics similar to the wringers of Patent No. 2,592,575 in that the-compression spring 127 is effectively part of the toggle link 120. p In the pressure position of the toggle links, the top ice bar 118 receives a downward force from the compression spring 127 transmitted through the link 120 to the pivot 121. Whenever the upward moment on the frame 118 exceeds the downward moment from the spring 127, the frame 118 hinges upward about pivot 119 until the moments on the frame are balanced. Considering only the top frame and the toggle and spring 120, 122, 127, it can be seen that a downward force F exerted on the top frame at point 121 can be balanced by an upward force F at point 121 or by an upward force 2F at a point midway between points 119 and 121 or by an upward force 3F at a point one-third the distance from point 119. In other words, the downward forces on the top frame due to the spring 127 vary inversely with the distance from point 119 being greater as point 119 is approached and less as point 121 is approached. The leverage or mechanical advantage of spring 127 increases as the pivot 119 is approached.
Since the top bar 118 is pivoted or hinged at one end of the wringer, the pressure characteristics due to the toggle vary from a minimum at the far end of the top frame to a maximum at the pivot end of the top frame. In view of this pressure variation, it has heretofore been considered necessary to provide some form of pressure equalizer. pressure equalizer is eliminated by using the variable spring characteristics of the rubber rolls to compensate for the variation in roll pressure due to the roll pressure mechanism. This is accomplished by adjusting the spacing of the roll bearings 1 14 and 116 so that the rolls are less compressed at the end where the pressure due to the roll pressure mechanism is greatest. As can be seen in Fig. l, the roll axes are not parallel as in the conventional construction, but converge toward the toggle end of the rolls. This results in a greaater compression of the rolls at the toggle end and a substantially lesser compression at the head end. In other Words, where the distortion of the rolls is greater, their resistance to further pressure applied thereto is greater. For example, at line 33 in Fig. l, the rolls have greater resistance to further pressure than at line 22 in Fig. 1. Conversely, the separating force between the rolls is greater at line 33 than at line 2-2.
Before wringing is started, the roll pressure varies along the length of the rolls as is indicated by the variable compression of the rolls in Figs. 2 and 3. As soon as material is fed between the rolls, there will be separation of the rolls and an additional compression on the rolls and a pivotal or hinging movement of the top bar resisted by the pressure mechanism. At the far end of the rolls where the leverage of the pressure mechanism is smallest, the rolls are compressed to a point where further compression is substantially impossible. The wringing pressure is therefore primarily due to the pressure mechanism. .At the head end of the wringer rolls where the leverage due to the pressure mechanism is greatest, the rolls are less compressed and until the rolls are com ressed to the condition indicated in Fig. 3, the effect of the increased leverage of the roll pressure mechanism is neutralized.
The effect of the rolls and of the pressure mechanism can be analyzed by considering what would happen (a) if the rolls 112 and 113 were perfectly rigid and (b) if the rolls were as disclosed but the top frame 118 were rigidly fixed to the bottom frame.
(a) If the rolls 112 and 113 were perfectly rigid, then as clothes were fed between the rolls, the rolls would separate. Considering the force of the spring 127 as P, if the clothes were fed at a point midway between points 119 and 121, the force on the clothes or the wringer pressure would be 2F. If the clothes were fed at the head end of the rolls, the force on the clothes In the present construction the- 3 would be approximately 3F while at the outer end the force would be approximately F for the proportions illustrated in Fig. 1. That is, with perfectly rigid rolls, the wringing pressure would increase toward the head end of-therolls.
([2) Now, taking the second step 'in the analysis and assuming the top frame 113 were rigidly fixed to the bottom frame, for example, by substituting a rigid member for the spring 127, then the rolls could not separate as clothes were fed between the rolls but the entire wringing pressure would be due to the compression of the rolls. At line 33 where the rolls initially are very substantially compressed, the wringing pressure would be greatest while at line 22 the wringing pressure would be less. In other words, the component of wringing pressure from the rolls would decrease toward the head end of the rolls.
By properly adjusting the spacing of the bearings it is possible to obtain substantially uniform wringing throughout the length of the rolls. The wringing effect is more uniform than that obtainable with the equalizers of the other wringer constructions which tend to provide a maximum wringing pressure at the center of the rolls and a minimum at the ends of the rolls. By adjusting the 'roll bearing spacing in the previously described constructions the need of the equalizers can be eliminated.
From one aspect the compensation of the roll pressure along the length of the rolls can be considered as due to the fact that the rolls have a variable spring rate or resistance to compression which varies along the length of the rolls in the opposite manner to the variation in pressure due to the roll pressure mechanism. In the present construction the variable spring rate of the rolls is due'to the increasing resistance to compression resulting from the increased area of contact as the rolls are compressed. The same effect could be obtained by varying the effective stiffness of the rubber throughout the length of the rolls with the softest rubber at the head end of the rolls. This may be accomplished by the roll constructions of Figs. 4 and 5. In Fig. 5, the roll has a conical core 132 of hard or stiff rubber and an outer cylindrical covering 132a of soft rubber. If the roll bearings are adjusted so the roll deflection is uniform when the toggle is set, the resistance to further compression of the roll will be greatest at the toggle end and least at the head end of the wringer, duplicating the results obtained with the Fig. 1 construction. With the rolls of Pig. 5 the roll shafts may be parallel. With the conical rolls 13% of Pig. 4, roll bearings are initially set so the line of contact between the rolls is parallel to the roll shafts. The greater compression of the rubber at the toggle end results in a roll stiffness which varies along the length of the rolls in a sense opposite to the pressure variation due to the toggle.
The improved uniformity of wringing can be explained as due to the shape of the roll pressure wringing curve (moisture removed vs. pressure) which increases rapidly at light pressures and levels off at high pressures. The slope of the wringing curve is steepest for thin material and the maximum useful wringing pressure is smallest. For thin material, the roll pressure is sufficient to obtain uniform wringing throughout the length of the rolls. For thick material at the toggle end of the rolls, the necessary additional pressure is obtained by deflection of the toggle spring. At the head end of the roll, the additional pressure is obtained partly by deflection of the toggle spring and partly by further compression of the rolls.
The superior wringing is also due to the fact that the upper roll cannot tilt relative to the top bar but is con strained'to hinge with the top bar. With the conventional equalizer construction the wringing has been greatest at the center of the rolls and has fallen off toward the ends. While wringing thick material at the ends, the roll tilt has increaased the falling off in wringing at the ends. In the present construction where the rolls cannot tilt relative to the top bar, the falling off in wringing'at'the ends of the rolls is decreaased. If the roll hearings (or the roll construction) are not adjusted to secure uniform wringing, the uniformity of wringing is improved over that obtainable with the equalizer construction. In other words, elimination of the equalizers in the wringers of Patent No. 2,592,575, without adjusting the roll bearings, would improve the wringing. Instead of setting the roll bearings to compensate for the variation in roll pressure due to the toggle, the roll bearings may be set to accentuate the pressure variation. The wringing will then be least at the toggle end and greatest at the head end and the operator may determine the dryness by the position of the clothes along the length of the rolls.
In the modifications shown in Figs. 6-8, corresponding parts are indicated by the same reference numerals.
In Fig. 6, the top bar 118 is hinged at 119 and at its other end is releasably locked to the side stile 111 by a toggle comprising an outer link 120a hinged at 121 to the top bar and at a to an inner link 122a hinged at 123 to the side stile. The hinge points 121, 12 3, and 125a are short of dead center so the toggle has to be held in the pressure position by the latch 129 and 131 as in the Fig. 1 construction.
The chief difference in the Fig. 6 wringer is in the arrangement for applying roll pressure. The upper ends of the bearings 116 engage a channel 133 hinged at 134 on the top bar. The usual leaf spring 135 bears on the channel with a pressure determined by the adjustment screw 136. Tilting of the upper roll 112 is prevented just as effectively as in the Fig. 1 wringer and there is the further advantage that the roll pressure is easily adjustable by the screw 136.
Another construction in which the upper roll is constrained to hinge toward and away from the lower roll is shown in Fig. 7 where a leaf spring 137 is hinged at 138 on the top bar 113 and has its pressure adjusted by the usual screw 159. The spring 137 bears directly on the upper ends of the bearings 116.
In Fig. 8, the top bar 118 is not rigidly locked to the wringer frame, as in Figs. 6 and 7, but is urged downward by trapped coil springs 149 arranged between the under side of a flange 141 on side stile 111a and the heads 142 of pins 143. The pins 143 extend up through the coil springs 14b and have their upper ends provided with heads 14% on the upper side of flange 145 on a channel 146 slidable on the side stile 111a. The channel 146 carries the pivot 123:: for the shorter toggle link 122a, the toggle links 122a and 12% being unstable as in the previously described wringers and being held in the pressure position by the safety release latch 12? and 131. The top bar 118 has fixed abutments 147 engaging the bearing blocks 116 but the adjustable abutments of Fig. I. could be used.
In all of the wringers the tilting of the roll about a cross axis through the middle of the roll which has heretofore been considered necessary is either prevented entirely or at least limited. The net result isthat while wringing thick pieces at one end of the rolls, the upper roll 112 cannot tilt so as to transfer wringing pressure to the opposite end where it is not needed.
In the claims, the term rubber is used to include equivalent resilient materials.
What I claim as new is:
l. In a wringer, a driving head, a lower frame extending from the head, an upper frame pivoted on the head, roll pressure spring mechanism connected between the upper and lower frames at the end of the frames opposite the head exerting a moment hinging the upper frame toward the lower frame, and a pair of rolls surfaced with resilient rubber and respectively journaled in the upper and lower frames on axes converging toward the roll pressure mechanism.
2. In a wringer, upper and lower frames hinged at one end, a pair of rolls surfaced with resilient rubber like material and comprising an upper roll journaled on an axis fixed with respect to the upper frame and a lower roll journaled on an axis fixed with respect to the lower frame, and roll pressure mechanism yieldably swinging the frames together and holding the rolls in ringing pressure engagement, the separation of the axes at said one end of the rolls being greater than the separation of the axes at the other end of the rolls.
3. In a wringer, a head, a rigid lower frame having a lower roll journaled on a fixed axis therein, a rigid upper frame having an upper roll journaled on a fixed axis therein, the rolls being surfaced with resilient rubber like material, the axes of the rolls converging away from the head, a hinge on the head for the upper frame, and a toggle for swinging the upper frame toward the lower frame and holding the rolls in wringing pressure engagement, said toggle comprising links pivoted to each other and respectively to the upper and lower frames, one of said toggle links including a trapped coil spring exerting a force along the length of the link.
4. In a wringer, a pair of rolls surfaced with resilient rubber like material, roll pressure mechanism including members hinged to each other at one end of the rolls and including spring means resiliently resisting separation of the members by relative swing movement of the members about said one end of the rolls whereby the roll pressure due to said mechanism varies along the length of the rolls, and roll supports arranged in pressure transmitting relation between the pressure members and spaced close enough together to cause initial compression of the rubber like material, said roll supports being spaced further apart at said one end of the rolls than at the other end of the rolls whereby the resistance to further compression of the rubher like material of the rolls is less at said one end than at the other end to compensate for the variation in roll pressure from the roll pressure mechanism.
5. The wringer of claim 4 in which the pressure members comprise a frame having a top bar and a pressure member hinged to the top bar at one end of the rolls.
6. The wringer of claim 5 in which the spring means is a leaf spring arranged between the top bar and the pressure member.
7. The wringer of claim 4 in which the rolls are supported in a frame and in which the spring means and one of the pressure members is a leaf spring hinged to the frame at one end of the rolls.
8. The wringer of claim 4 in which the pressure mem bers comprise a lower frame with side stiles at each end in which the roll supports are slidable and a top bar hinged at one end of the rolls and carrying abutments engaging the roll supports, and in which the spring means comprises a slide carried on the side stile opposite said one end of the rolls, a releasable connection between. the top bar and the slide, and a coil spring urging the slide downward.
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