Manually Releasable Vacuum Holding Base Construction

Abstract

The generally rectangular open bottom base rests on a generally rectangular resilient pad, and a yoke connected with the pad extends upwardly from the central portion thereof for vertical movement in the turning of a crank operating through a slot in the yoke. This crank is at the mid-portion of a cross-shaft disposed parallel to the pad and supported for rotation in registering bearing holes provided in opposed walls of the base, a manually operable lever bent nearly at a right angle to one end of the shaft outside the base serving to turn the shaft and crank to cup the central portion of the pad for suction cup action. Small projections molded integral with the pad at the four corners of the base have locating abutment with these corners inside the base and besides being thereby concealed for good appearance are free to move radially inwardly in the cupping of the pad so there is no interference with this operation. Also, a C-shaped spring clip is applicable to a cutout portion of the shaft next to the inside of the base at the lever end of the shaft to define shoulders on the shaft for abutment with the adjacent wall of the base to complete the assembling of the shaft in the base, the pad being flexible away from the base sufficiently to permit this final step in the assembling.

Description

This invention relates to a manually releasable vacuum holding base construction for temporarily securely holding portable devices, such as pencil sharpeners and the like, on most any available flat surface.

The principal object is to provide a simpler and more economical, and, at the same time, better appearing vacuum base construction, in which:

1. The resilient pad on which the base rests and which serves as a suction cup to fasten the base to a supporting surface is of uniform thickness in the peripherally exposed portion and devoid of any exposed unsightly locating or retaining projections, whatever molded projections are provided on the pad for locating abutment with the base at the corners, being all neatly concealed within the base;

2. The resilient pad is readily flexible away from the bottom of the base enough to permit assembling a spring clip over a shouldered portion of the crankshaft inside the base to secure it in place so that there is no need for an exposed retaining screw on the outer end of the shaft, this spring clip being completely concealed inside the base for improved outer appearance of the base, and

3. The stress applied to the central portion of the resilient pad to pucker it up for the suction cup effect is, by virtue of the improved design, distributed uniformly in all directions throughout the pad area for the best available suction cup effect and at the same time the least amount of wear and tear on the pad for increased life, the molded locating projections on the corners of the pad being not only concealed inside the base but free to move radially inwardly inside the base so as not to interfere with the puckering up of the central portion.

The invention is illustrated in the accompanying drawing, in which:

FIG. 1 is a side view of a pencil sharpener, the hollow generally rectangular base portion of which is shown in vertical cross-section to better illustrate my improved vacuum base construction, the parts being shown in holding position securing the base firmly on a flat supporting surface by suction cup action;

FIG. 2 is a cross-section on the line 2--2 of FIG. 1;

FIG. 3 is a bottom view of the base showing the bottom pad flexed outwardly at one corner to expose the retaining spring clip for the crankshaft which is applied to a shouldered portion at one end of the shaft while the pad is flexed outwardly at one corner in the manner shown to complete the assembling of the pencil sharpener;

FIG. 4 is a plan view of the pad showing in dotted lines the outline of the bottom of the pencil sharpener base to indicate how the molded projections on the pad fit in the corners on the inside of the base to maintain good registration without interfering with the convexing or puckering up of the central portion of the pad for the suction cup action;

FIG. 5 is a perspective view of the retaining spring clip, and

FIG. 6 is an enlarged sectional detail on the line 6--6 of FIG. 2, showing how the spring clip is fastened to the shaft where it is cutaway on one side to define shoulders, thereby using the spring clip as a simple and easily applied locking device.

Similar reference numerals are applied to corresponding parts throughout the views.

Referring to the drawing, the reference numeral 10 designates the hollow generally rectangular base provided on the lower end of the upright frame 11 of a pencil sharpener 12, the latter being of a conventional type operable by a hand-crank 13 to sharpen a pencil inserted between the usual converging cutters that are rotated and moved in a circular orbit in the usual way by operation of the crank, the pencil being held in the appropriate sized hole in the rotatably adjustable pencil holder 14 provided on the front of the chip receptacle 15. The present improvements, as previously mentioned, are embodied in the manually releasable vacuum holding base construction for temporarily securely holding the pencil sharpener on any available flat surface, during the operation thereof, and to that end, the improvements are incorporated principally in the rectangular base 10 and its cooperating resilient molded rubber pad 16 that is also of generally rectangular form like the base 10, but of appreciably larger dimensions overall, so that the marginal edge portions 17 of the pad project beyond the lower edges of the base's side and end walls 18 and 19, respectively, as seen in FIGS. 1 and 2 and also indicated in dotted lines in FIG. 4. The pad's bottom surface 20, which is normally flat and adapted to rest on a flat supporting surface 21, remains in engagement with the supporting surface only around the marginal edge portions of the pad when the generally rectangular thicker central portion 22 of the pad is forced upwardly to define a suction cup by means of the generally rectangular plate 23 and its upwardly extending yoke 24 by turning the cross-shaft 25 and its integral crank 26 by means of the lever 27 provided on one end of the shaft. A bumper tip 28 applied to the outer end of the lever 27 cushions its engagement with the top of a desk or the like on which the surface 21 is provided, thereby silencing the operation and avoiding marring the finish.

Two things are noticeable immediately in the resilient pad 16 aside of course from its having the molded thick rectangular central portion 22 with its rectangular pocket 29 in which the rectangular plate 23 is fixed as an insert in the molding operation, namely:

1. that the entire marginal portion 30 of the pad is of substantially uniform thickness throughout and there is, therefore, nothing to interfere with the upward displacement of the central portion 22 relative to the marginal portion 30 in the cupping upwardly of the pad for the suction cup action, and

2. that the four generally L-shaped corner projections 31 provided on top of the four corner portions of the pad 16 in equally inwardly spaced relation to the edges, as best appears in FIG 4, fit loosely inside the four corners of the base 10 to maintain good registration of the pad with the base for uniform projection of the marginal edge portions of the pad outside the base both before and after cupping of the pad, which is important for best operation, but these projections are movable radially inwardly in the cupping of the pad and therefore the outer edges of the pad also drawing inwardly to some extent in the cupping of the pad, and there is therefore the best possible suction cup action for the best possible gripping of the pad on the flat surface 21.

The crank 26 is rotatable and slidable in a horizontal slot 32 provided in the vertical upwardly projecting generally rectangular yoke portion 24 of the plate 23 that is loosely guided at its opposite ends for up and down movement in the spaced parallel vertical channels 34 cast integral with and extending downwardly from the top wall 35 of the hollow base 10. The shaft 25, on which crank 26 is provided intermediate its ends, has bearing support at its opposite ends in registering holes 36 provided in opposed side walls of the base. The shaft 25 is cut away on one side, as at 37, next to the journal end portion 38 from which the lever 27 extends nearly at right angles, and the C-shaped spring clip 39, which is of the same width as the cut out portion and is adapted to be snapped into place therein as shown in FIGS. 2 and 3, uses the ends of the cutout portion as locating shoulders to prevent slippage of the clip endwise of the shaft while the clip itself serves to define shoulders annularly of the shaft on diametrically opposite sides, as at 40, for abutment with the side wall of the base 10 to limit endwise movement of the shaft 25 outwardly.

The lever extension 27 is close enough to its inner end of the outside of the base 10 to limit endwise movement of the shaft 25 inwardly. Hence, very little endwise movement of the shaft is permitted with this construction and there is no need for supplying a large head screw applied to the end of the shaft 25 with the head exposed on and abutting the outside of the base remote from the lever 27 to limit inward movement of the shaft. The clip 39 can be applied to the shaft 25 at 37 through the open bottom of the base 10 as the last step in assembling the pencil sharpener by merely flexing a corner portion of the pad 16 away from the open bottom of the base, as shown in FIG. 3. The clip 39 has divergingly curved ends 41 to facilitate its being spread enough to be slipped over the cut-away portion 37.

It is believed the foregoing description conveys a good understanding of the objects and advantages of my invention. While a preferred embodiment of the invention has been illustrated and described, this is only for the purpose of illustration, and it is to be understood that various modifications in structure will occur to a person skilled in this art.

Claims

I claim:

1. In a vacuum base construction of the character described comprising a hollow generally rectangular open bottom base, a resilient pad of generally rectangular form and larger length and width dimensions than said base on the central portion of which said base is mounted, said pad having an inner face in abutment with the base and an outer substantially flat face for abutment with a flat supporting surface, means rendering the central portion of said pad comparatively stiff and having a yoke extending therefrom substantially at right angles inwardly relative to the central portion of said base for transmitting axial movement to said central portion inwardly relative to the central portion of said base for a suction cup formation of said pad while it is in engagement with a flat supporting surface for vacuum holding action, and a cross-shaft disposed in substantially parallel relation to said pad and rotatably mounted in bearings in opposed walls of said base and having a crank portion thereon intermediate its ends slidably and rotatably engaged in a slot provided in said yoke and having a manually operable lever rigid with one end thereof outside said base for turning said shaft and said crank with it, the improvements which consists in providing a shouldered recess portion on said shaft at one end in proximate spaced relation to one of said bearings, said lever including an abutment portion on the other side of said bearing from said recess immediately adjacent the wall defining said bearing, said pad being flexible away from said base sufficiently to expose said recess portion of said shaft and the adjacent bearing, and a generally C-shaped spring clip applicable from outside the base into axially immovable engagement with said recess portion of said shaft serving to limit endwise movement of said shaft outwardly of said base while said abutment portion of said lever limits endwise movement of said shaft in the opposite direction, said C-shaped spring clip being the sole means fastening said shaft in assembled relation to said base.

2. In a vacuum base construction of the character described comprising a hollow generally rectangular open bottom base, a resilient pad of generally rectangular form and larger length and width dimensions than said base on the central portion of which said base is mounted, said pad having an inner face in abutment with the base and an outer substantially flat face for abutment with a flat supporting surface, means rendering the central portion of said pad comparatively stiff and having a yoke extending therefrom substantially at right angles inwardly relative to the central portion of said base for transmitting axial movement to said central portion inwardly relative to the central portion of said base for a suction cup formation of said pad while it is in engagement with a flat supporting surface for vacuum holding action, and a cross-shaft disposed in substantially parallel relation to said pad and rotatably mounted in bearings in opposed walls of said base and having a crank portion thereon intermediate its ends slidably and rotatably engaged in a slot provided in said yoke and having a manually operable lever rigid with one end thereof outside said base for turning said shaft and said crank with it, the improvement which consists in projections provided on the inner side of said resilient pad for locating abutment with the inner side of the corner portions of said base, whereby said projections move radially inwardly toward one another to some extent in the cupping of the pad and leave the marginal portions of said pad in the cupping thereof free also to be gathered in to whatever extent is necessary and thereby secure maximum vacuum cup action for a good hold on the supporting surface, the entire marginal portion of said pad outside of the central portion being of substantially uniform thickness throughout for uniform stress reaction radially in the cupping of the pad, said marginal portion being free from projections disposed in the path of said base.

3. The apparatus of claim 2 wherein said lever includes an abutment portion disposed exteriorly of a wall of said base immediately adjacent one said bearing, said shaft includes a recess disposed immediately adjacent the interior of said wall of said base, a generally C-shaped spring clip adapted to be mounted on said recess from outside the base by peeling back said pad, said shaft being limited from axial movement relative to said base by said abutment in one direction and by said clip in the other direction, said clip forming the sole means fastening said shaft in assembled relation to said base.