CA2494477C - Variable angle corner tool - Google Patents

Abstract

An adjustable corner tool is provided having outwardly biased blades. The back surfaces of the blades are connected to an angle control assembly that includes fixed-length arms pivotally connected between each of the blades and a central mounting block. Springs rotationally bias the arms away from each other such that the arms push against the back surfaces of the blades to urge the blades apart. In use, resistive force applied against the front surfaces of the blades moves the blades together. Thus, the adjustable corner tool dynamically adjusts to variations in wall corner angles. The adjustable corner toot can be used with corners in the range of about 160 degrees to 40 degrees and the angle of the tool can also optionally be fixed or maximally limited. In addition, the adjustable corner tool may be adapted to also function as an injection head for delivering spreadable material to a corner.

Description

1 "VARIABLE ANGLE CORNER TOOL"

2

3 FIELD OF THE INVENTION

4 The invention relates to adjustable corner tools and in particular to variable angle corner tools for use in finishing corners with spreadable material 6 such as drywall compound.

9 Drywall corner tools are commonly used to finish wall corners provided by adjacent intersecting walls. Many conventional drywall corner 11 finishing tools in the marketplace are limited to applications against typical 90 12 degree angular inside corner wall joints. In recent years, the use of other angular 13 measurements have been incorporated in building construction, resulting in larger 14 and smaller angles than 90 degrees, such as vaulted ceilings or corner bay window coves.
16 Angles other than 90 degrees can be finished by hand using a joint 17 knife or variable angle hand trowel. This method is very time consuming since 18 each side of the angle must be finished separately and allowed to dry. To assist 19 in this finishing process, a product called "corner bead" was made available in a variety of popular angles, which is placed into the corner to fill the joint gap and 21 provide a straight vertical corner line before drywall compound (mastic or mud) is 22 applied and finished by hand. Such corner bead strips, however, increase the 23 cost of drywalling.
24 To alleviate problems associated with variable wall corner angles, drywall corner tools have been developed having adjustable corner angles. For 1 example, such tools have been disclosed in U.S. Patent Nos.: 5,442,832, issued 2 on August 22, 1995; 5,467,497, issued on November 21, 1995; 5,544,384 issued 3 on August 13, 1996; and Patent No. 5,774,924, issued on July 7, 1998. Each of 4 these patents disclose corner tools having hinged blades for pivotal movement of the blades about the hinge axis to form a variety of corner angles. Slideably or 6 pivotally connected arms extend between the blades to support the blades and 7 adjust the blades to a desired corner angle. Typically, the angle is fixed by a 8 locking member that prevents sliding or rotation of the arms about the handle 9 prior to use. Alternatively, the '497 patent discloses a locking pin bolt extending through the hinge for fixing the blades at a desired angle.
11 In some cases, a particular wall corner angle is variable, either by 12 design or because the corner is not true, such that fixedly variable angle corner 13 tools may not adequately finish such a corner. Although it is possible to not fix 14 the angle of the prior art corner tools to allow the blades to move together for adjusting to decreasing wall corner angles during use, the blades will not 16 automatically return to their original position or adjust to increasing wall angles.
17 There is, therefore, a need for an improved adjustable corner tool.

2 An improved adjustable corner tool for finishing wall corners with 3 spreadable material is provided that allows the angle defined by the blades of the 4 corner tool to dynamically adjust to variations in wall corner angles during use.
The corner tool can be used for finishing wall corners in the range of about 6 degrees to 40 degrees and can also be fixed at a specific angle is so desired, 7 therefore is useful for a wide variety of applications.
8 In one embodiment invention, the adjustable corner tool comprises 9 a pair of hinged blades that are outwardly biased to urge the blades apart and whereby force applied against the blades moves the blades together. To 11 outwardly bias the blades, an angle control assembly is connected between the 12 back surfaces. Generally, the angle control assembly includes a central 13 mounting block, fixed-length arms pivotally connected to each of the blades and 14 the central mounting block, and springs that rotate the arms away from each other to thereby outwardly bias the blades. Preferably, pairs of spaced upper and 16 lower arms are used to optimize the transfer of force between the angle control 17 assembly and the length of the blades. Furthermore, while only one spring is 18 required to outwardly bias the blades, preferably at least twa springs are used, 19 with each spring acting on an arm connected to one or the other blades. The invention may also be adapted to suit a variety of purposes. For example, the 21 arms can be clamped to resist or prevent rotation and thereby substantially fix the 22 angle of the corner tool. Stops that prevent rotation of the arms can also be used 23 to define a maximum angle of the corner tool.
24 In a broad aspect of the invention, there is provided an adjustable corner tool comprising: first and second blades, each blade having a mating 1 edge, a front surface and a back surface, the blades hingedly connected at the 2 mating edges, the back surfaces defining an angle; and an angle control 3 assembly connected between the back surfaces, the angle control assembly 4 outwardly biasing the blades to urge the blades apart to increase the angle and wherein pressure applied against the front surfaces moves the blades together to 6 thereby decrease the angle.
7 In another broad aspect of the invention, there is provided an angle 8 control assembly for a corner tool having first and second blades, each blade 9 having a mating edge, a front surface and a back surface, the blades hingedly connected at the mating edges, the back surfaces defining an angle, the angle 11 control assembly comprising: first and second mounting plates; and a mounting 12 block pivotally connected between first and second mounting plates, the angle 13 control assembly outwardly biasing the first and second mounting plates for 14 moving the plates apart, wherein attachment of the first mounting plate to the first blade and attachment of the second mounting plate to the second blade 16 outwardly biases the blades to urge the blades apart to increase the angle and 17 wherein pressure applied against the front surfaces moves the blades together to 18 thereby decrease the angle.
19 The adjustable corner tool may be used with any spreadable material, such as drywall compound, plaster, and grout. Although the adjustable 21 corner tool is intended for use in finishing wall corners, it can be used in any 22 application in which finishing of such spreadable material in a corner is required.
23 The adjustable corner tool may also be modified to also function as an injection 24 head for applying spreadable material to a corner.

2 In drawings which are intended to illustrate embodiments of the 3 invention and which are not intended to limit the scope of the invention:
4 Figure 1A is a back perspective view of one embodiment of an adjustable corner tool of the present invention;
6 Figure 1 B is a back perspective view of the angle control assembly 7 of Fig. 1A shown in isolation from the blades;
8 Figure 2 is a front perspective view of the adjustable comer tool 9 according to Fig. 1;
Figures 3A-C are top plan views of another embodiment of a corner 11 tool of the present invention, with the blades actuated to 160 degrees (with the 12 stops removed in Fig. 3A), 95 degrees and 40 degrees, respectively;
13 Figure. 4 is a back view of the adjustable corner tool of the present 14 invention according to Fig. 3B
Figures 5A and 5B are top plan and bottom plan views, 16 respectively, of the adjustable corner tool according to Fig. 1;
17 Figure 6 is an exploded view of the adjustable corner tool according 18 to Fig. 1;
19 Figure 7 is a perspective view of a blade of the adjustable corner tool of the present invention;
21 Figure 8 is a top plan view of an embodiment of a portion of the 22 hinge connection of an adjustable corner tool of the present invention having a 23 beveled mating edge; and

5 Figure 9A is a bottom plan view and Figure 9B is a back view of 2 another embodiment of an adjustable corner tool of the present invention having 3 an injection head modification.

6 2 Referring to Figs. 1 A-3C, a variable angle corner tool 100 is shown 3 having generally planar outwardly biased first and second blades 10a, 10b 4 connected at mating edges 12 by a hinge 14 and an angle control assembly 16 positioned between the back surtaces 18a, 18b of the blades 10a, 10b. Herein, 6 the surface of the blades 10a, 10b which engage the wall are deemed to be the

7 front surface 26a, 26b and the opposing surface accessed by an operator is a

8 back surface 18a, 18b. The angle control assembly 16 maintains a general V

9 arrangement of the blades 10a, 10b and allows the angle A defined by the back surfaces 18a, 18b to be dynamically adjusted from about 160 degrees to 40 11 degrees, as particularly seen in Figs. 3A-C. The angle control assembly 16 12 includes a mounting block 20 positioned between the back surfaces 18a, 18b, 13 pivotal connections 22 between each of the mounting block 20 and the first and 14 second blades 10a, 10b, and outwardly biasing means 24. The pivotal connections 22 allow the blades 10a, 10b to move apart or together upon 16 application of appropriate force to the blades 10a, 10b, typically initiated through 17 the mounting block 20. In particular, outwardly biasing force provided by the 18 outwardly biasing means 24 urges the blades 10a, 10b apart to thereby increase 19 the angle A, while reactive force applied against the front surfaces 26a, 26b acts against the outwardly biasing force to move the blades 10a, 10b together to 21 thereby decrease the angle A.
22 The mounting block 20 also provides a point of attachment for a 23 handle (not shown), such as a pole, to assist the user in the operation of the 24 corner tool 100. As shown, the mounting block 20 provides a socket 28 between 1 upper and lower ends 30, 32 for accommodating a pole with a conventional ball 2 joint and as secured by a retaining spring clip 34.
3 With further reference to Figs. 4-6 the pivotal connections 22 of the 4 angle control assembly 16 are provided by pivotally connected arms 36a, 36b, 38a, 38b extending at a fixed length between the mounting block 20 and the 6 blades 10a, 10b. More particularly, each of a spaced apart first upper arm 36a 7 and first lower arm 38a is pivotally connected at a distal end 40 to the first blade 8 10a, while each of a spaced apart second upper arm 36b and second lower arm 9 38b is pivotally connected at a distal end 40 to the second blade 10b, with the upper arms 36a, 36b and lower arms 38a, 38b each pivotally connected at a 11 proximal end 44 to upper and lower ends of the mounting block 30, 32. For 12 connection of the arms 36a, 36b, 38a, 38b to the blades 10a, 10b, first and 13 second mounting plates 48a, 48b are attached to the first and second blades 14 10a, 10b. A pair of upper and lower posts 50, 52 extend perpendicularly from each of the mounting plates 48a, 48b to which the upper arms 36a, 36b and 16 lower arms 38a, 38b are respectively attached.
17 The mounting plates 48a, 48b are attached to the blades 10a, 10b 18 by any suitable means, such as bolts 49 or welding. While the mounting plates 19 48a, 48b may be of any suitable shape (Figs. 1A and 4), mounting plates 48a, 48b that substantially cover the back surfaces 18a, 18b, as particularly seen in 21 Fig. 4, are preferred for providing structural support to the blades 10a, 10b.
22 Pivotal connection of the arms 36a, 36b, 38a, 38b is achieved by 23 passing a suitable pivot fastener 54, such as a rivet, pin or bolt, through aligned 24 pivot holes 56 formed in the arms 36a, 36b, 38a, 38b, mounting plates 48a, 48b, and mounting block 20, as required. Preferably, each pair of upper arms 36a, 1 36b and lower arms 38a, 38b are pivotally connected to the mounting block 20 by 2 a single pivot fastener 54, thereby providing a common pivot point for each pair of 3 upper arms 36a, 36b and lower arms 38a, 38b. The pivot fasteners 54 can be 4 adjustable to clamp the arms 36a, 36b, 38a, 38b to provide variable resistance to pivotal movement of the arms 36a, 36b, 38a, 38b or to lock the arms 36a, 36b, 6 38a, 38b in place at a specific angle, as desired. For example, as shown, the 7 pivot fastener 54 is a threaded bolt whereby the fastened arm is retained 8 between the head of the bolt 58 and a nut 60 threaded onto the shaft 62. To 9 clamp the arms 36a, 36b, 38a, 38b, the nut 60 is simply threaded further onto the shaft 62, while loosening of the nut 60 will unclamp the arm 36a, 36b, 38a, 38b.
11 Alternatively, upper and lower fasteners may interconnect to form such a nut-and-12 bolt arrangement, as seen in Fig. 4.
13 In general, the outwardly biasing means 24 acts between any of the 14 arms 36a, 36b, 38a, 38b and the mounting block 20 to rotate the respective arm 36a, 36b, 38a, 38b about the pivot fastener 54, while the arms 36a, 36b, 38a, 38b 16 act between the mounting block 20 and the blades 10a, 10b to move the blades 17 10a, 10b outwardly and away from each other. In particular, the outwardly 18 biasing means 24 includes upper and lower springs 64, 66 attached to the first 19 upper arm 36a and the second lower arm 38b, respectively. To pre-load the springs 64, 66, a distal end of each spring 66 is secured to its respective arm 21 36a, 38b, a proximal end of each spring 69 is secured to the mounting block 20, 22 and the coils of the springs 64, 66 are positioned about a biasing post 70.
23 Conveniently, the biasing posts 70 correspond to the pivot fasteners 54 24 positioned on the mounting block 20, with a bushing 71 and washer 72 also positioned around the fastener 54. The springs rotationally bias the arms 36a, 1 38b to rotate the arms 36a, 38b away from each other so that the mounting block 2 20 moves toward the back surfaces 18a, 18b (see Figs. 3A-3C) causing the arms 3 36a, 38b to push against the blades 10a, 10b and urge the blades 10a, 10b 4 apart. In other words, the upper spring 64 acts on the first upper arm 36a to outwardly bias the first blade 10a, while the lower spring 66 acts on the second 6 lower arm 38b to outwardly bias the second blade 10b. Alternatively, the upper 7 and lower springs 64, 66 may be inversely attached to the upper second arm 36b 8 and lower first arm 38a without affecting the overall operation of the corner tool 9 100.
Any suitable means for securing the distal and proximal ends of the 11 springs 68, 69 may be used. As shown, the distal end of the springs 68 are 12 hooks that are inserted into spring holes 74 formed in the arms 36a, 38b, while U-13 shaped proximal ends 68, 69 are positioned about spring retainer pins 76 14 attached to the upper and lower ends of the mounting blocks 30, 32 and adjacent to the respective biasing posts 70. To prevent the spring retainer pins 76 from 16 interfering with the pivotal movement of the arms 36a, 36b, 38a, 38b, cut-outs 78 17 are provided in the arms 36a, 36b, 38a, 38b, as required.
18 In use for finishing a wall corner, the outwardly biased blades 10a, 19 10b of the corner tool 100 form a first angle that is larger than the maximum angle of the wail corner. The corner tool 100 is then placed in the wall corner, 21 generally having drywall compound or other spreadable material applied thereto, 22 with the front surfaces 26a, 26b engaging the walls. Moderate pressure is 23 applied upon the mounting block 20 towards the blades 10a, 10b to push the 24 corner tool 100 into the wall corner and, consequently, resistive forces applied to the blades 10a, 10b compress the springs 64, 66 and cause the blades 10a, 10b 1 to move together to form a second angle corresponding to the angle of the wall 2 corner. As the corner tool 100 is stroked along the length of the wall corner with 3 continual application of pressure to spread the compound, the angle A of the 4 blades 10a, 10b will adjust to substantially always match the angle of the wall corner. In particular, the combination of the outward biasing and the pivotal 6 connection of the blades 10a, 10b allow the angle A to dynamically increase or 7 decrease according to variations in the wall corner angle, such as if the corner is 8 not true.
9 Preferably, the first angle of the blades 10a, 10b is slightly larger than the maximum angle of the wall corner. For example, for a right angle wall 11 corner, the first angle may be 95 degrees. To restrain the blades 10a, 10b to a 12 maximum angle, stops 80, such as bolts, are positioned on the mounting block 20 13 adjacent to an outer edge 82 of each of the arms 36a, 36b, 38a, 38b to restrict 14 rotational biasing of the arms 36a, 38b, 38a, 38b. If the desired first angle is larger that maximally permitted by the stops 80, the stops 80 may be removed as 16 necessary, as seen in Fig. 3A. In addition, the placement of stops 80 beside 17 pairs of first and second arms 36a, 36b, 38a, 38b also act to help keep the 18 mounting block 20 centered to the blades 10a, 10b, particularly if the user is 19 standing off center of the comer tool 100 when pressure is being applied.
While the invention has thus far been described with respect to the 21 preferred embodiment, other embodiments are also contemplated. For example, 22 outwardly biasing means 24 may be attached to all of the arms or to only one arm 23 36a, 36b, 38a, 38b. Alternatively, only one pair of first and second arms 36a, 36b 24 or 38a, 38b can be used with outwardly biasing means 24 attached to one or both arms 36a, 36b, 38a, 38b. Notably, the use of outwardly biasing means 24 for 1 biasing both the first and second blades 10a, 10b allows force to be applied 2 equally through to both blades 10a, 10b if uneven force is applied, such as if the 3 user is standing off-centre of the corner tool 100. In addition, the arrangement of 4 the spaced apart upper and lower arms 36a, 36b and 38a, 38b provides structural support along the length of the corner tool 100 as force is being 6 applied.
7 With reference to Figs. 6 and 7, the blades 10a, 10b may be of any 8 shape suitable for the construction and purpose of the corner tool 100. As 9 shown, the blades 10a, 10b are as found in a typical drywall flusher head, with each blade having a general wing shape with angled tips 84 and lower edges 86 11 and downwardly projecting sliders 88 extending from each of the front surfaces 12 26a, 26b.
13 Any hinge connection that permits pivotal movement of the blades 14 can be used. For example, with reference to Figs. 7 and 8, the hinge 14 is a piano hinge formed from spaced apart hinge cylinders 90 projecting from and 16 extending along the mating edge 12 of each of the blades 10a, 10b. The hinge 17 cylinders 90 are aligned for receiving a rod 92 therethrough, such that the mating 18 edge 12 of each blade 10a, 10b is adjacent to the hinge cylinders 90 of the other 19 blade 10a, 10b. In general, the hinge connection should be substantially flush with the front surfaces 26a, 26b to minimize impact on the surface of the finished 21 corner. Furthermore, with particular reference to Fig. 8, the mating edge 12 may 22 be chamfered or beveled inwardly to allow for a substantially tight fitting of the 23 mating edge 12 with the hinge member 90 and therefore allow for a smoother 24 finish. For example, for a hinge having an outer diameter of about 1/8", the mating edge is beveled at about 60 degrees.

1 The corner tool 100 may be made of any material suitable for the 2 purpose for which it is intended, including metal, plastic, or a combination thereof.
3 In addition, the corner tool 100 may be constructed in any manner which 4 achieves the ultimate function. For example, the posts 50, 52 may be integrally formed with the blades 10a, 10b such that mounting plates 48a, 48b per se are 6 not required.
7 Referring to Figs. 9A and 9B, the corner tool 100 can be modified to 8 also function as an injection head for applying spreadable material, such as 9 drywall compound, to a wall corner. In this case, the socket 28 in the mounting block 20 accommodates a compound conduit having a ball member (not shown) 11 and the socket 28 is adapted to include a cavity 98. Tubing 94 is connected 12 between openings (not visible) in the mounting block 20 and the blades 10a, 10b, 13 where the openings in the mounting block 20 are in communication with the 14 cavity 98. Preferably the mounting block 20 would have increased depth to accommodate the cavity 98 and the openings therein.
16 In use, a pump delivers drywall compound through the compound 17 conduit to the socket 28 and the compound is injected into the cavity 98.
The 18 compound then flows through the tubing 94 to the front surfaces 26a, 26b of the 19 blades 10a, 10b, where the compound can be spread along a wall corner with the corner tool 100, as described previously. If necessary, seals (not shown) are 21 used to prevent leakage of compound from the socket 28.
22 One or more tubing 94 can be used, as desired, and the tubing 94 23 can be made of any flexible material that permits movement of the blades 10a, 24 10b. For example, as shown, the tubing 94 is plastic and fittings 99, such as 1 brass fittings, are used to connect the tubing 94 to the mounting block 20 and the 2 blades 10a, 10b. The tubing 94 can also be made of metal having hinged joints.
3 Although preferred embodiments of the invention have been 4 described in some detail herein above, those skilled in the art will recognize that various substitutions and modifications of the invention may be made without 6 departing from the scope of the invention as defined by the claims as defined 7 herein.

Claims (20)

THE EMBODIMENTS OF THE INVENTION FOR WHICH AN
EXCLUSIVE PROPERTY OF PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:

1. An adjustable corner tool comprising:

first and second blades, each blade having a mating edge, a front surface and a back surface, the blades hingedly connected at the mating edges, the back surfaces being adjustable, defining an adjustable angle within the range of about 40 degrees to about 160 degrees; and an angle control assembly connected between the back surfaces, the angle control assembly outwardly biasing the blades to urge the blades apart to increase the angle and wherein pressure applied against the front surfaces moves the blades together to thereby decrease the angle.

2. The adjustable corner tool of claim 1 wherein the angle control assembly further comprises a mounting block pivotally connected between the first and second blades.

3. The adjustable corner tool of claim 2 wherein the angle control assembly further comprises at least one pair of first and second arms, the first arm pivotally connected at a distal end to the first blade and pivotally connected at a proximal end to the mounting block, the second arm pivotally connected at a distal end to the second blade and pivotally connected at a proximal end to the mounting block, at least one of the arms rotationally biased to outwardly bias the blade attached thereto, thereby urging the blades apart.

4. The adjustable corner tool of claim 3 wherein both arms are outwardly biased.

5. The adjustable corner tool of claim 3 having a pair of first and second upper arms and a pair of first and second lower arms, the upper and lower pairs of arms spaced apart to sandwich the mounting block therebetween, the first upper arm being outwardly biased and the second lower arm being outwardly biased.

6. The adjustable corner tool of any one of claims 3 to 5 wherein the angle control assembly further comprises releasable clamping means for providing resistance to the rotational movement of the arms.

7. The adjustable corner tool of any one of claims 3 to 6 wherein the angle control assembly further comprises at least one stop member for limiting the outward rotation of one of the arms.

8. The adjustable corner tool of claim 7 having first and second stop members, the first stop positioned on the mounting block adjacent to an outer edge of the first arm, the second stop positioned on the mounting block adjacent to an outer edge of the second arm.

9. The adjustable corner tool of any one of claims 3 to 8 wherein the angle control assembly further comprises first and second mounting plates, the first mounting plate attached to the back surface of first blade and the second mounting plate attached to the back surface of second blade, the first arm pivotally attached to the first mounting plate and the second arm pivotally attached to the second mounting plate.

10. The adjustable corner tool of any one of claims 1 to 9 wherein the angle control assembly outwardly biases the blades by a spring.

11. The adjustable corner tool of any one of claims 1 to 10 wherein the mating edges are beveled inwardly, the beveled edge of each blade adjacent to a hinge cylinder projecting from the mating edge of the other blade, wherein the beveled edge and the hinge cylinder form a substantially tight fit sufficient to produce a smooth finish.

12. The adjustable corner tool of any one of claims 2 to 11, the mounting block adapted to receive a conduit for spreadable material, the adjustable corner tool further comprising:

tubing connected between the mounting block and the back surface of at least one of the blades, the tubing in communication with an opening in the mounting block and an opening end in at the at least one of the blades, wherein the tubing directs spreadable material delivered from the conduit into the mounting block to the front surface of the at least one blade.

13. An angle control assembly for a corner tool having first and second blades, each blade having a mating edge, a front surface and a back surface, the blades hingedly connected at the mating edges, the back surfaces being adjustable, defining an adjustable angle within the range of about 40 degrees to about 160 degrees, the angle control assembly comprising:

first and second mounting plates; and a mounting block pivotally connected between first and second mounting plates, the angle control assembly outwardly biasing the first and second mounting plates for moving the plates apart, wherein attachment of the first mounting plate to the first blade and attachment of the second mounting plate to the second blade outwardly biases the blades to urge the blades apart to increase the angle and wherein pressure applied against the front surfaces moves the blades together to thereby decrease the angle.

14. The angle control assembly of claim 13 further comprising at least one pair of first and second arms, the first arm pivotally connected at a distal end to the first mounting plate and pivotally connected at a proximal end to the mounting block, the second arm pivotally connected at a distal end to the second mounting plate and pivotally connected at a proximal end to the mounting block, at least one of the arms rotationally biased to outwardly bias the mounting plate attached thereto, thereby moving the mounting plates apart.

15. The angle control assembly of claim 14 wherein both arms are outwardly biased.

16. The angle control assembly of claim 14 having a pair of first and second upper arms and a pair of first and second lower arms, the upper and lower pairs of arms spaced apart to sandwich the mounting block therebetween, the first upper arm being outwardly biased and the second lower arm being outwardly biased.

17. The angle control assembly of any one of claims 14 to 16 further comprising releasable clamping means for providing resistance to the rotational movement of the arms.

18. The angle control assembly of any one of claims 14 to 17 further comprising at least one stop member for limiting the outward rotation of one of the arms.

19. The adjustable corner tool of claim 18 having first and second stop members, the first stop positioned on the mounting block adjacent to an outer edge of the first arm, the second stop positioned on the mounting block adjacent to an outer edge of the second arm.

20. The angle control assembly of any one of claims 13 to 19 wherein the angle control assembly outwardly biases the mounting plates by a spring.