Patent Application
20200122294
The present invention relates to dust collection. In particular, examples of the present invention relates to a shroud for tools such as angle grinders.
Dust collection is important for commercial processes and construction as well as for consumer or hobbyist use of power tools. Without adequate dust collection while working, dust and debris is typically scattered over a wide area. It is desirable to contain the dust and debris which is created while using power tools for several reasons. It is desirable to contain the dust and debris to keep the workplace cleaner and to minimize the time necessary to clean up afterwards. For example, angle grinders are often used to cut or grind cement. Grinding materials such as cement creates fine dust which is spread over a large distance and can be quite difficult to clean up afterwards. It is also desirable to contain the dust and debris to keep the debris from getting into the tool itself, as the fine dust often causes premature failure of the tool bearings, motor, etc. Additionally, dust poses a health risk to the machine operator and others who may breathe it. It is thus desirable to collect the dust to minimize any exposure to the dust.
Non-limiting and non-exhaustive examples of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity. The drawings have been drawn to scale to allow for easier understanding of the device. Common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.
It will be appreciated that the drawings are illustrative and not limiting of the scope of the invention which is defined by the appended claims. The examples shown each accomplish various different advantages. It is appreciated that it is not possible to clearly show each element or advantage in a single figure, and as such, multiple figures are presented to separately illustrate the various details of the examples in greater clarity. Similarly, not every example need accomplish all advantages of the present disclosure.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one having ordinary skill in the art that the specific detail need not be employed to practice the present invention. In other instances, well-known materials or methods have not been described in detail in order to avoid obscuring the present invention.
Reference throughout this specification to “one embodiment”, “an embodiment”, “one example” or “an example” means that a particular feature, structure or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, “one example” or “an example” in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures or characteristics may be combined in any suitable combinations and/or sub-combinations in one or more embodiments or examples. In addition, it is appreciated that the figures provided herewith are for explanation purposes to persons ordinarily skilled in the art.
Many angle grinders 14 include a stock blade guard (not shown) which covers a portion of a grinding wheel. The blade guard helps keep debris from hitting the operator. These blade guards, however, do not capture the grinding dust produced by the grinder 14. It is becoming increasingly common for manufacturers to use proprietary quick release attachment systems for blade guards which allow the blade guard to be rotated to different positions around the grinding wheel. These quick release attachment systems make it increasingly difficult to provide a dust collection shroud 10 which fits different angle grinders 14. The shroud 10 provides a mounting system which adapts to different angle grinders 14 and is adjustable to different angle grinders 14 despite the various structures used to mount the original blade guards.
The shroud 10 is used to collect the grinding dust and capture the dust to reduce the environmental and health impact of using the angle grinder 14. The shroud 10 includes a shroud body 38 which is attachable to the angle grinder 14 to enclose the grinding wheel 34. The shroud body 38 includes an upper portion 42 and a sidewall 46 which extends downwardly from the upper portion. The upper portion 42 and sidewall 46 form a dust collection chamber 50 which is generally enclosed and which has an open bottom. As shown, the sidewall 46 is generally round as viewed from above and may be formed with a curved transition between the sidewall and the upper portion 42. The bottom edge of the sidewall 46 may be formed with a channel that receives a skirt 58. The skirt 58 is flexible and contacts the work surface which is being ground by the grinder around the grinding wheel 34 to assist in collecting dust. The skirt 58 may be a flexible plastic or rubber. In this example, the skirt 58 is formed by a plurality of plastic bristles held together in a crimped metal ring. The bristles form a generally continuous skirt wall which is round and encircles the dust collection chamber 50 along the lower edge of the shroud sidewall 46. The skirt 58 is typically preinstalled into the shroud sidewall 46.
The shroud body 38 includes an exhaust port 62. The exhaust port 62 is attached to the upper portion 42 and sidewall 46 so that it is oriented tangentially to the outside of the cup wheel 34 and shroud body 38. The exhaust port 62 opens from the shroud body 38 so that it flows smoothly from the shroud body 38 and continues in the direction of rotation of the cup wheel 34. The exhaust port 62 has an interior bore or passage which is connected to the interior dust collection chamber 50 so that dust can move from the dust collection chamber 50 through the exhaust port 62. In some situations, the exhaust port 62 may be connected to a vacuum to extract dust from the dust shroud body 38. The exhaust port 62 may thus be sized to receive a nominal 1.25 inch or 1.5 inch vacuum hose 66 (or a larger hose for larger shrouds/grinders).
The shroud 10 is attached to the angle grinder 14. Many angle grinders 14 include a shoulder 70 which extends downwardly from the gearbox 26 surrounding the grinder output shaft 30. The shoulder 70 may house bearings to support the output shaft 30. The shoulder 70 of the angle grinder 14 may be generally circular, but often includes registration or attachment features for the original blade guard. These attachment features often interfere with attachment of an aftermarket dust collection shroud 10. The upper portion 42 of the shroud body 38 has a hole 74 therethrough. The hole 74 through the upper portion 42 of the shroud body is typically located in the center of the upper portion of the shroud body. The output shaft 30 of the grinder 14 passes through the hole 74 and into the dust collection chamber 50 so that the cup wheel 34 or other grinding attachment is located in the dust collection chamber 50 when assembled. The hole 74 in the upper portion of the shroud body 38 is larger than the output shaft and is sufficiently large to fit a variety of grinders. A rubber sealing gasket 78 is attached to the top of the shroud body 38 to seal around the output shaft 30; keeping dust contained inside of the dust collection chamber 50 and keeping dust separated from the grinder motor and bearings. The sealing gasket 78 is formed with a number of holes 82 which are spaced apart near its outer edge. The holes 82 are placed over corresponding attachment tabs 86 formed on the top surface of the shroud body 38 around the hole 74.
The shroud 10 includes an attachment structure which is attached to the upper portion 42 of the shroud body 38 and which attached the shroud 10 to the angle grinder 14. In order to accommodate a variety of different angle grinders with a single shroud 10, the shroud includes three movable mounting arms/mounting brackets 90 which are attached to the shroud body 38 so that they may be moved in and out to different distances from the center of the hole 74 and so that they may be moved around the hole 74 to different angular positions around the hole 74. The mounting brackets 90 may be moved to different positions around the opening 74 to accommodate different shoulders 70 of different grinders 14.
The slots 94 include a first slot section 94A which allows the mounting bracket 90 to move inwardly and outwardly relative to the hole 74, a second slot section 94B which allows the mounting bracket 90 to move inwardly and outwardly relative to the hole 74, and a third slot section 94C which connects the first slot section 94A and the second slot section 94B and allows the mounting bracket 90 to move laterally to different positions around the hole 74. In the example shown, the first slot section 94A and the second slot section 94B are oriented in radial alignment with the hole 74 and shaft 30 so that the mounting bracket 90 is movable directly towards or away from the shaft 30 and collar 70. The third slot section 94C is oriented circumferentially around the hole 74 so that the mounting bracket is movable to a different radial position around the output shaft 30 and collar 70. This allows the operator to select between different positions for the mounting bracket 90 while attaching the mounting bracket 90 to the collar 70. If the collar 70 includes an attachment feature for the stock blade guard which interferes with the placement of the mounting bracket 90, the mounting bracket may be moved to a different location in the slot 94 (e.g. from the first slot section 94A to the second slot section 94B). The mounting brackets are located in the first slot sections 94A or second slot sections 94B when the shroud 10 is attached to the grinder 14 to allow the mounting brackets 90 to move into position against the collar 70. As shown, one of the slots 94 may be made with only a first slot section 94A. This provides for one mounting bracket 90 which is in a fixed location around the hole 74. In attaching the shroud 10 to the grinder 14, this mounting bracket may be placed to avoid any mounting features for the stock blade guard and the other mounting brackets 90 may be moved within their slots 94 as discussed to avoid any other mounting features. Each of the slots 94, however, may contain a first slot section 94A, a second slot section 94B, and a third slot section 94C.
The mounting brackets 90 are attached to the shroud body 38 by pins 98 which pass through the slots 94 and through the mounting brackets 90. Each of the pins 98 has a head on the lower end which does not pass through the slots 94 and engages the shroud body 38. The shank of the pin passes through the slot 94, through a washer 102 and a spring 106, through a hole in the mounting bracket 90, and is secured with a fastener such as an e-clip 110 (or not, etc.) on the upper end to secure the pin 98 to the mounting bracket 90. While the present invention describes the use of springs 106, it will be appreciated that other biasing elements such as an elastomeric tubing will provide the desired amount of flexibility and movement. Compression of the springs 106 allows some vertical movement between the mounting brackets 90 and the shroud body 38, allowing the shroud body 38 to move vertically relative to the mounting brackets 90 and the grinder 14. This allows the operator flexibility in choosing which part of the grinding disk 34 contacts the work surface and in choosing how much pressure to apply to the work surface while grinding. In a resting position, the springs 106 exert a force which pushes the mounting brackets 90 away from the shroud body 38 and biases the shroud body 38 away from the angle grinder 14. This places the bottom of the skirt 58 near (preferably below) the bottom surface of the grinding wheel 34. When an operator brings the grinding wheel 34 into contact with a work surface, the skirt 58 first contacts the work surface and then remains in contact with the work surface while the grinding wheel 34 is then pushed downwardly (along with the grinder 14 and mounting brackets 90) relative to the shroud body 38 and skirt 58 to bring the grinding wheel 34 in contact with the work surface. This arrangement maintains the skirt 58 in contact with the work surface and improves the collection of dust generated while grinding.
A clamp such as a worm drive hose clamp 114 engages shoulders or slots formed on the inward ends of the mounting brackets 90 and is used to securely fasten the mounting brackets 90 to an angle grinder 14 so that the output shaft 30 of the angle grinder 14 passes through the hole 74 and the grinding wheel 34 is located in the dust collection chamber 50. If desired, the interior faces of the mounting brackets 90 which contact the grinder shoulder 70 may be lined with an elastomeric facing, or may include ridges 118 which engage a groove in the shoulder 70 to improve the attachment of the shroud 10 to the angle grinder 14.
These figures better illustrate the sealing gasket 78. As discussed, the sealing gasket 78 is attached to the top of the shroud body 38 to seal around the output shaft 30. The sealing gasket 78 is formed with a number of holes 82 which are spaced apart near its outer edge as well as an output shaft hole 122 at its center. The attachment tabs 86 formed on the top surface of the shroud body 38 extend upwardly from the shroud body 38 and then extend outwardly from the hole 74 in a L or hook shape. The holes 82 are placed over the attachment tabs 86 to secure the sealing gasket 78 to the shroud body 38. While the hole 74 is oversized relative to the grinder output shaft 30, the gasket hole 122 is closely sized to the output shaft 30. If desired, a few sealing gaskets 78 with different sizes of holes 122 may be provided to accommodate common grinders 14.
In use, the shroud 10 is generally pre-assembled, but may require attachment of a sealing gasket 78 and the clamp 114 to the shroud body 38 and mounting brackets 90. The shroud 10 is secured to the angle grinder 14 and a grinding or sanding attachment such as the diamond grinding wheel 34 is installed onto the grinder output shaft 30. The bottom end of the grinder output shaft 30 is typically threaded to allow grinding attachments to be attached thereto. When the grinding attachment 34 is secured in place, the bottom cutting surface of the grinding attachment 34 is typically located below the plane formed by the bottom edge of the sidewall 46 and above the plane formed by the bottom edge of the skirt 58. If the skirt 58 is formed of plastic bristles, for example, it will compress vertically somewhat to maintain contact with an uneven work surface and the springs 106 allow the shroud body 38 to move vertically to allow the bottom cutting surface of the grinding attachment 34 to contact the work surface to grind that surface while keeping the skirt 58 in contact with the work surface to contain dust. A vacuum which is attached to the exhaust port 62 via hose 66 draws air and dust inwardly through slots 94 and through the skirt 58, from around the grinding wheel 34, through the exhaust port 62, and into the vacuum where it is collected. The air flow and dust tend to rotate with the grinding wheel 34 and are carried to the exhaust port 62.
The dust collection shroud 10 may have additional features such as a removable access hatch 126. The access hatch 126 is removable to expose a small amount of the grinding wheel 34 such that the outer cutting edge of the grinding wheel extends beyond the remaining edge of the shroud body 38 after removal of the access hatch 126. This allows an operator to grind against a vertical surface, such as when grinding a floor against a wall.
The dust collection shroud 10 is advantageous as it allows for convenient attachment of a single dust collection shroud 10 and system to a variety of different angle grinders 14. The shroud is easily used and is convenient for an operator, promoting compliance in using the dust collection system. This promotes a clean work environment and reduces health hazards to the operator and others in the area. The shroud 10 is able to capture most of the dust created while grinding.
The above description of illustrated examples of the present invention, including what is described in the Abstract, are not intended to be exhaustive or to be limitation to the precise forms disclosed. While specific examples of the invention are described herein for illustrative purposes, various equivalent modifications are possible without departing from the broader scope of the present claims. Indeed, it is appreciated that specific example dimensions, materials, etc., are provided for explanation purposes and that other values may also be employed in other examples in accordance with the teachings of the present invention.
