US2541330A - Sander - Google Patents

Description

Feb. 13, 1951 c c, BOURDUNls 2,541,330

SANDER Filed Jan. 6, 1950 2 Sheets-Sheet 1 INVENTOR. Con dent n? C Boarduzzi;

Patented Feb. 13, 1951 UNITED STATES PATENT OFFICE 6 Claims.

The present invention relates to devices known as sanders and which consist essentially of a supportin structure on which a piece of sandpaper may be properly mounted for sanding operations.

A sanding device of the type with which this invention is concerned consists essentially of a base plate having a curvature which particularly adapts it to the sanding operation, means for detachably securing a piece of Sandpaper on the lower exposed face of said base plate, and a handle that is attached to the base plate and which is adapted to be grasped by the operator in performing the sanding operations.

An important object of the present invention is to provide new and improved means'for securely clamping a piece of sandpaper in position on the base plate. In carrying out this objective the upper face of the base plate is serrated along the end edges. The piece of sandpaper is longer than the base plate and the protruding end portions are folded back over these serrated surfaces.

A somewhat more detailed object is to provide new and improved means for clamping these turned-back end portions of the sandpaper against the serrated surfaces.

In attaining the latter object a bracket is anchored to the base plate on the face remote from that which carries the sandpaper, and this bracket has an upstanding arm which pivotally carries a cam lever. A clamping plate is formed with a slot which receives the upstandin arm of the bracket and this clamping plate is engaged by the cam of the cam lever. The clamping plate has an outer marginal turned-down flange which engages the turned-back sandpaper over the serrated surface. Thus, the cam lever may be actuated to force the clamping plate downwardly and cause the fian e thereon to press the sandpaper against the serrated surface or it may be operated I to relieve the pressure on the cam plate to permit withdrawal of the sandpaper.

Under conditions of practical usage, it is desirable that the cam plates be urged upwardly into positions freeing the turned-back edges of the sandpaper when the cam levers are operated to relieve pressure on the cam plates.

Thus, a further object of the invention is to provide spring devices which are interposed between the cam plates and the base plates and which normally tend to separate the cam plates from the base plate.

The invention contemplates at least two arrangements for fulfilling this objective. In one form a spring-clip is provided as aseparate element which is removably positioned between each cam plate and the base plate. This clip has a central bowed portion which funct ons as a spring and is formed with a slot that receives the upstanding bracket arm. One end of the clip carries a flange which engages the end edge of the cam plate in positioning the clip. In the other form a leaf spring is permanently secured to that portion of the bracket which is anchored to the base plate. This leaf spring has upwardly extending end portions which engage the cam plate.

Another highly important object of the present invention is to provide a new and improved handle that is secured to thebase plate substanti'ally midway the ends thereof. In accordance with the present invent on this handle is preferably made of plastic and the handle is so designed as to be extremely light using a minimum amount of material and yet is sufficiently rugged to withstand the service conditions and is also so designed as'to afford a secure anchorage for the elements which connect it to the base plate.

Variovs'other more detailed objects and advantages of the invention such as arise in connection with carrying out the above noted ideas in a practical embodiment will, in part become apparent,-and in part be hereinafter stated as the description of the invention proceeds.

The invention therefore comprises a sander of the type including a base plate, a handle carried by the, base plate, and means for clamping a piece of" sandpaper in position on the base plate with the invention residing primarily in im rovements in the clamping means and the handle.

For 'a full and more com lete understanding of the invention, reference may be had to the following description and accompanying drawings wherein:

Figure 1 is a View in side elevation of a sander embodying the improvements of this invention.

Figure 2 is a view in end elevation of the sander shown in Figure 1.

Figure 3 is a tran verse vertical section'taken about on the plane represented by the line '3-3 of Figure 1.

Figure 4 is a perspective developing certain elements of the clamping mechanism in exploded relation.

Figure 5 is a view in side elevation of a modified form of handle with the base plate broken away.

Figure 6 is a view in end elevation of the handle shown in Figure 5 with the base plate shown in section; and

Figure 7 is a detailed perspective-showing a 3 modified form of spring for the clamping mechanism.

Referrin now to the drawings wherein like reference characters denote corresponding parts, and first more particularly to Figures 1 to 4, inclusive, the sander of'thi invention is shown as including as an essential element a base plate l having a lower or exposed convex surface H and an upper concave surface I2. The base plate H! is of generally rectangular formation and is intended to have a strip of material or piece of sandpaper such as represented at i3 applied over the convex surface H. paper is longer than the base plate I0 and the protruding end portions which are designated M are folded back over the marginal end portions of the upper concave surface 12 in abutting relation therewith. These marginal end portions are serrated as indicated at IE to provide for a good gripping engagement of the sandpaper therewith when the sandpaper is clamped thereagainst.

The base plate i0 is formed with two frustroconical openings such as represented by. the broken lines at It in Figure 1. These openings receive the heads 11 of screws l8 which are employed to anchor the handle in position as will be later described. The heads I! have a shape corresponding to the openings [6 so that they fit snugly therein and do not protrude beyond the exposed convex surface I l of the base plate I 0.

Mounted on the upper concave surface 12 of the base plate H! are two clamping assemblies, each of which is identified by the reference char acter C. There is a clamping assembly C at each end of the base plate and as these assemblies are substantial duplicates only one of them is herein described in detail fo the purpose of this specification.

Each clamping assembly C includes a bracket having a, base portion [9 that is anchored to the upper concave surface I2 of the base plate In in any preferred manner such as by the screw shown at 20 and an upstanding arm 2| projecting from the base plate In adjacent to and spaced from one end thereof. Pivotally mounted on the arm 2! adjacent the projecting end thereof by a pivot pin 22 is a-cam lever 23. The cam lever 23 is adapted for movement about an axis transverse on the arm 2!. The latter includes a handle portion 24 and a cam portion 25 that is disposed adjacent to the pivotal mounting 22. This cam lever 23 is preferably made of metal but is of the cutout construction illustrated in Figures 2, 3 and 4 to lighten the structure.

A clamping plate is designated 26 and is formed with a slot at 21 through which the upstanding bracket arm 2| passes. The clamping plate 26 has an end flange 28 which engages the turnedback portion it of the sandpaper above the serrated surface I5. This clamping plate 26 is normally engaged by the cam 25 of the cam lever so thatupon rotation of this cam'25 as an incident to swinging of the lever the clamping plate 26 is urged downwardly against the base plate in by the cam.

A spring clip is shown in Figure 4 and is referred to in its entirety by the reference character S. The spring clip S includes a centrally bowed body portion 29 that is formed with a slot 3!! and an end flange 3!. The body portion 29 of the sprin clip is inserted between the clamping plate 26 and the base plate IB with the slot 33 receiving the upstanding bracket arm The piece l3 of sand- 2|. As the clip is positioned the end flange 3| abuts the end edge of the clamping plate 23 and thus limits the positioning movement. The normal tendency of the spring clip S is to maintain the clamping plate 23 spaced from the base plate !0 so as to free the turned-back edge portion !4 of the sandpaper. However, this tendency of the spring clip is overcome when the cam lever 23 is operated to urge the flange 28 of the clamping plate 26 against the turnedback end M of the sandpaper.

Upon referring to Figure '7 a modified arrangement for maintaining the clampingplate spaced from the base plate is therein illustrated. In this form, a leaf spring L has a central fiat portion 32 that is secured to the upper face of the base IQ of the bracket by the same screws 20 which secure the bracket in position on the base plate H1. Outstanding from this central fiat portion 32 from the opposite ends thereof and in upwardly diverging directions are spring arms 33 and 34. The ends of these spring arms 33 and 34 engage the underface of the clamping plate 26. It is evident that the normal tendency of this leaf spring L is to maintain the clamping plate 26 spaced from the base plate l0.

Referring now again to Figures 1, 2 and 3, the handle for the sander will now be described. This handle is referred to in its entirety by the reference character H. It is preferably made of plastic which is susceptible of being molded into the desired shape. The handle H comprises a main body portion 35 which is of the hollow oval formation illustrated in Figures 2 and 3. Extending downwardly from this main body portion 35 towards the base plate I0 is a central web 36 and a pair of end legs 31 and 38. With the web 36 and end legs 31 and 38 considered as a single unit, this unit has a lower curved surface which is complemental to and engaged with the upper concave surface l2 of the base plate HI.

Each of the legs 31 and 38 is formed with an opening at 40 in which is received a metallic block 4 l Each of the metallic blocks 4| is formed with a threaded bore 42 which receives the threaded portion of one of the screws IB. Thus, the reception of the screws l8 in the blocks 4| with the latter positioned in the openings 40 in the legs 31 and 38 securely anchors the handle H to the base plate ID.

A modified form of handle is illustrated in Figures 5 and 6. This handle assembly is referred to in its entirety by the reference character HI. The handle assembly HI comprises a U-shaped bracket having a back 43 that is curved to conform to the curvature of the concave surface l2 of the base plate [0 and to which it is secured by the screw and nut assemblies represented at 44. Upstanding from this back 43 are arms 45 and 46 which carry between their free. ends a bolt 4'! on which the handle proper is mounted as shown at 48.

Operation vice a piece is first selected having a length greater than the length of the base plate I0. That is, the piece which is to be applied must be comparable to that shown-at l3-in the drawings. The

operator. now. operates the ,cam lever 23 to relieve pressure on the clamping plates 23. As this amnesia pressure is relieved either the spring clips S or the springs L will force the clamping plates 26 up- Wardlyahdaway from thebase plate I U V v Thesandpaper piece [3 is now positioned-over the convex surface II of the base plate in a smooth condition and the edge portions I d folded back and inserted beneath the flanges 28; of the clamping plates '26. The operatorthen turns the cam levers 23 so that the cams 25 thereof force the cam plates 26 down against the base plate Ill. As this action takes place the flanges 28 engage the turned-back ends M and force these turned-back ends against the serrated surfaces to securely lock the sandpaper piece l3 in position.

After the sandpaper piece I3 has been subjected to continued use so as to become worn, it is replaced by first operating the cam levers 23 to relieve pressure on the cam plates 26, whereupon the sandpaper piece may be removed and a new piece substituted, therefore, in .the manner above described.

While preferred specific embodiments of the invention are hereinbefore set forth, it is to be clearly understood that the invention is not to be limited to the exact constructions, mechanisms, and devices illustrated and described because various modifications of these details may be provided in putting the invention into practice within the purview of the appended claims.

What is claimed is:

1. In a sander including a curved base plate having convex and concave surfaces and a handle, and which base plate is adapted to receive a piece of sandpaper over its convex surface with end ortions of the sandpaper folded back over the end portions of the concave surface, the improvement consisting of serrations on the end portions of said concave surface against which the turned-back end portions of the sandpaper are adapted to engage, and means for clamping said turned-back edges against said serrated surfaces, said means comp-rising a pair of brackets secured to the concave surface of said base plate, and each having an arm upstanding therefrom, a cam lever pivotally mounted on each of said upstanding arms, and a clamping plate interposed between each cam lever and said base plate and adapted to engage the turned-back edge of the said sandpaper.

2. In a sander including a curved base plate having convex and concave surfaces and a handle, and which base plate is adapted to receive a piece of sandpaper over its convex surface with end portions of the sandpaper folded for clamping said turned-back edges against said serrated surfaces, said means comprising a pair of brackets secured to the concave surface of said base plate, and each having an arm upstanding therefrom, a cam lever pivotally mounted on each of said upstanding arms, and a clamping plate slidably positioned over each of said upstanding arms, each of said clamping plates having a slot receiving the respective arm, and a marginal flange extending toward said base plate and adapted to engage the turned-back edge of the sandpaper thereat.

3. In a sanding device of the character described, the combination of a base plate adapted to have a piece of sandpaper applied thereto with 6 an end portion of-the sandpaper folded back over an endpithe base plate, and a clamping device for clamping said turned-back edge against said base plate, v said clamping device comprising a bracket secured to said base plate and having an arm outstanding therefrom, a clamping plate having a slot receiving said arm with the clampiiig plate slidable over said arm and movable relative to said base plate, anda cam lever pivotally mounted on said arm and having a cam portion engaging said clamping plate.

4. In a sanding device of the character described, the combination of: a base plate adapted to have a piece of sandpaper applied thereto with an end portion of the sandpaper folded back over an end of the base plate, and a clamping device for clamping said turned-back edge against said base plate, said clamping device comprising a bracket secured to said base plate and having an arm outstanding therefrom, a clamping plate having a slot receiving said arm with the clamping plate slidable over said arm and movable relative to said base plate, a flange on one edge of said clamping plate extending toward said base plate and adapted to engage the turned-back edge of the sandpaper, and a cam lever pivotally mounted on said arm and having a cam portion engaging said clamping plate.

5. A sanding device comprising a base plate adapted to have a strip of material applied on one surface thereof with the end portions of said strip folded back over the ends of said base plate and abutting the other surface of said base plate, a first arm projecting from said other surface of said base plate adjacent to and spaced from one end thereof, a second arm projecting from said other surface of said base plate adjacent to and spaced from the other end thereof, a clamping plate slidably positioned on each of said arms, a cam mounted on each of said arms adjacent the projecting ends of the latter for movement about an axis transverse of said arms, rotation of the adjacent cam urging the adjacent clamping plate toward said base plate and causing the adjacent clamping plate to press the adjacent end portion of said strip against said base plate, and a handle positioned on said other surface of said base plate intermediate the ends thereof and secured thereto.

6. A sanding device comprising a curved base plate having concave and convex surfaces and adapted to have a strip of material applied on said convex surface thereof with the end portions of said strip folded back over the ends of said base plate and abutting said concave surface of said base plate, a first arm projecting from said concave surface of said base plate'adiacent to and spaced from one end thereof, a second arm projecting from said concave surface of said base plate adjacent to and spaced from the other end thereof, a clamping plate slidably positioned on each of said arms, a cam mounted on each of said arms adjacent the projecting ends of the latter for movement about an axis transverse of said arms, rotation of the adjacent cam urging the adjacent clamping plate toward said base plate and causing the adjacent clamping plate to press the adjacent end portion of said strip against said base plate, and a handle positioned on said concave surface of said base plate intermediate the ends thereof and secured thereto.

CONSTANTINE C. BOURDUNIS.

(References on following page) 7 8 7 REFERENCES CITED Number Name 'Date- The following references are of record in the 1183444 Flsk May 1916 file of this patent: 1,544,368 Brennen June 30, 1925 w 1,737,135 Wmdfeldt Nov. 26, 1929 UNITED STATES PA'I'ENTS 6 1,744,820 Wilding Jan. 28, 1930 Number Name Date v Kelley Apr. 26, 243,212 Piper Oct 11 1331 2,428,618 Dispensiere Oct. 7, 1947 403 433 Prevost 6, 1339 ,4 5 E ele Mar. 15, 1949 7 33 s n Man 23, 1905 44 K n Sept. 20, 1949 809,615 Hopkins Jan. 9, 1906 10

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