Patent Application
20200258492
The present invention relates to noise reduction and management for drilling tools. More specifically, the present invention provides a noise suppression device for use with hand operated machinery including, at least, drills, generally, and with jackleg drills used in mining operations particularly.
Mining, Digging, blasting, drilling, bolting and other activities intended to release and recover natural resources trapped underground have been employed for decades. Various precious jewels, minerals, and petroleum products have been harvested and recovered using these techniques. And, over time, the methods and tools used to recover such resources have been devised, refined, improved, and changed.
Early recovery included digging with hand tools. As time passed, miners developed techniques that included sluicing and devised machines that provided more power and more reach for digging and injecting fluids to encourage production. Petroleum products were among the materials mined.
One of the devices used in the mining process is the manually-applied power jackleg drill comprising a hard-surfaced rotary bit. The jackleg drill was developed during the industrial revolution and changed the way mining was accomplished. It provided a much more powerful, hand operated tool than was previously available. The jackleg drill, generally, can be set up and operated by one person. It typically comprises a cylinder, motor, and a throttle. A head, a chuck and a drill rod associated with the cylinder provides means to drill. The rod is, generally, one of 2, 4, 6 or 8 feet in length and often ⅞ inch hex. The leg is pneumatic to provide means to lift or lower the jack. A water line and a water valve can be provided to reduce dust production and provide cooling. The “leg” portion of its name refers to the hydraulic leg which facilitates adjustment in the height of the drill to be changed and to provide pressure against the rock face which is being drilled. Although technological advancements to the drill have been made, its basic design is still very much in use today.
Jackleg drills are used in a variety of mining operations, including those related to minerals, jewels, petroleum. Some drills are designed to be used both horizontally and vertically; some drills are specific to one or the other. Specifically, the drills are commonly used to drill into a rock face in order to position dynamite or other blasting material deep within its surface. The dynamite is then exploded and the material examined for the desired ore or mineral. The drill may also be used to place other equipment in the mine walls as needed such as support bolts. By using a hydraulic version of the drill (employing water or other fluid during the drilling process), miners were able to reduce the amount of dangerous airborne particles to which they were exposed during the mining process. In short, both the early versions and the hydraulic version of the jackleg drill made mining operations much safer for those involved which also increased the productivity of the workers who were trained to use them. However, the jackleg drill—whether hydraulic or not—and whether employed vertically or horizontally—still poses a danger to its operators in terms of noise. This danger is also posed to other workers that use hand operated tools comprising motors/engines and/or are intended for uses that drill, grind, hammer, or chisel.
To address the damage to workers resulting from the noise produced by the jack leg drills and other noise-emanating hand operated tools, regulations pertaining to the allowed exposure to noise in terms of decibels have been implemented and required. A drill operator wears a device that measures decibels over time and, when the limit is reached, that operator must cease operating the drill for a specified number of hours. Generally, this means other operators must be standing by to take over. And, because each task differs thereby effecting the rate at which noise exposure accumulates, the use of simple shift changes for operators is not always practical. Particularly, relevant regulations provide limitations for exposure. Based upon Federal Regulations sound power doubles every 5 dBA—it is a logarithmic scale. The table below exemplifies this principal:
MSHA and OSHA have established exposure/dosage limits and add a 2 dB error factor before citations are issued. So there is no possibility of the standard not being exceeded. For example:
The actual sound doubling rate for human hearing is 3 dBA. For this reason, both MSHA and OSHA define “effective” controls as any control or combination of controls which results in a 3 dBA reduction in sound or noise. Because the jack leg drill operation produces high sound density there is a need to manage exposure to noise such that an operator can operate the drill during his full shift without being exposed to more than the restricted amount of noise. Several inventions have addressed noise exposure. For example:
U.S. Pat. No. 6,427,782 provides a device for noise management for machines having hard surfaced rotary bits. It comprises a complex arrangement of perforated plastic, fiber glass liner and a shell and is associated with the drill so as to catch sound from the exhaust outlet of the drill. This device is relatively complex including all of the following for noise reduction; cushions 304D, perforated plastic 304C, fiber glass 304A, outer shell 304, and liner 304B.
U.S. Pat. No. 6,089,346 discloses use of acoustic barrier material within its housing and a frustoconical shape attached at the exhaust outlet. The muffler includes an inlet and an outlet and catches noise at the jack's exhaust port.
While both of the aforementioned devices help to manage noise that is “exhausted” with the machine's exhaust, they do not address noise that emanates from parts of the drill other than the exhaust system. There is, therefore, additional noise produced that is not being addressed.
A report by the US Department of the Interior entitled “Noise Reduction of a Pneumatic Rock Drill” published in 1975 and provided a well-described context of various testing of devices employed for noise abatement and related findings. None of the devices described by that report suggest the present invention. Further, although several more recent patents covering noise management devices were located, none suggest the present invention. Specifically, among the located patent documents are US Patent Application Nos. 2009/0090530 and 2009/0294211 which disclose simple muffler devices. Another device for muffling noise of a pneumatic device was presented by U.S. Pat. No. 6,089,346. The '346 discloses the use of acoustic barrier material within its housing and a frustoconical shape; the device is associated with the exhaust outlet, catching noise at the jack leg drill's exhaust port.
The inventive noise suppression device is very user friendly and designed to manage noise exposure to miners operating jackleg or other drills or noise-producing tools which are partially or completely hand operated. The device preferably includes an outer shell or cover which may comprise a durable material such as HDPE plastic and comprises an inner surface. The device not only reduces muffler noise but also the noise from the tool itself.
Generally, the device is a cover designed to “catch”/muffle sound as it exits a machine whether the noise exits through the machine's exhaust or other portions of the machine. The noise suppression device is designed to substantially encase portions of the drill machine in order to achieve the noise reduction objective. The device may comprise a conical end through which a drilling rod extends for drilling and through which a portion of the sound travels. With minor adjustment to the design, the device may be used with horizontal or vertical drilling operations, or with tools that employ different attachments that also product high noise levels. The present invention improves over other noise management devices such as earphones for the operator or a muffler associated with the exhaust on the drill. In general, the present invention comprises an improvement that reduces noise emanating from more than simply the exhaust of the drill's motor.
The present invention is a noise suppression device that fits over at least a portion of the body of the drill (or other tool) (which body may comprise a cylinder, controls, motor, and drill mechanics). The noise suppression device includes a first end (to fit over at least a portion of the rod of the drill or another attachment), noise suppressors such as an acoustic panel or echo absorber, at least one liner comprising noise reducing material such as rubber or mesh, a second end, and, usually, a skirt. The inventive noise suppression device installs in minutes and is lightweight. It can just as easily be removed for other applications of the too. In-mine testing shows that the device markedly reduces the rate of noise exposure, increasing time that its operator can work within the governmental guidelines pertaining to noise exposure. In short, the device measurably improves labor efficiency in the mine or other environment where noise-emanating hand-operated tools are employed, allowing miners to work a full shift without over exposure to noise.
Clearly, noise is a problem with hand-operated drilling machinery and other hand-operated motorized tools and has been addressed in various ways with varying levels of success including ear protection for the user, and mufflers associated with the exhaust of the machinery. The present invention will be described herein by reference numbers associated with figures. Two embodiments of the invention are presented as noise suppression devices 10 and 100. The invention is a noise suppression device 10, 100 for use with a drilling device 5 and works by “muffling” and “catching” noise using sound dampening materials 12 substantially covered or encased in an outer shell 14. The shell 14 also comprises an inner surface 15 and surrounds or partially surrounds a noise source 16 rather than simply accepting the noise from an exhaust outlet 20, as the prior art teaches. The noise source may comprise a motor 16 and a drill rod 18. (The noise source may, instead, comprise another hand-operated motorized drilling or other tool. Specifically, a first embodiment of the present invention is a noise suppression device 10 that fits over and fully or substantially surrounds at least a portion of a body 22 of the drilling device 5 (which device may comprise a cylinder 30, controls, drill mechanics 34, and, the rod 18). The device may comprise an outer shape which may be conical. (See
In a second embodiment shown at
In a third embodiment as shown in
In an embodiment, the skirt or skirting 48 comprises neoprene and may comprise a dimension generally equal to the second opening 47, 470. The skirting may be cone or funnel-like in shape, or may exhibit similar circumference or shape with the second end 46, 460. In an embodiment, shell 14, 414 comprises HDPE plastic or material of similar flexibility, strength, and durability which may include old filter casing material. Inner layer 44, 440 material may include rubber lining, Thinsulate®, or old filter casing material as echo absorber material thereby forming an acoustic panel 42, 420. The inventive device may be used for, at least, roof bolting and drilling. With minor adjustment the device may be employed in horizontal bolting and drilling operations, or employed for use with vertically operated jack hammers.
To use the noise suppressing device 10 in a vertical drilling operation, the drill rod 18 of a jack leg drill 5, e.g., (See
There are two ways to install the noise suppressing device 100 in a horizontal drilling operation. The first includes securing or placing the noise suppressing device 100 on a generally horizontal surface thereafter inserting the drill rod 18 of a drill through the first arched rib 500 at the first end 400, and through the second arched rib 520 at the second end 460. Alternatively, the drill comprising a drill rod 18 could be positioned first, with the noise suppressing device 100 placed over the drill 5 thereafter and, optionally, secured there. The covered arch shape allows the device 100 to be placed on and stably supported by a horizontal surface for use in horizontal drilling applications. Other than these factors, the vertical and horizontal embodiments may share common features.
Testing of the inventive device 10 shows measurable reduction in dba exposure from 104 to 97 during roof bolting. Reduction in dba translates to more work time per worker before the sound limit is reached. Data below shows three sets of data. Data for employee numbers 1-8 reports noise exposure to these employees when using typical noise reduction equipment. Data for employee numbers 9-17 was collected from employees using a first version of the noise suppression device, while data for employee numbers 18-23 was collected from employees using a second version of the noise suppression device. Data in terms of dosimeter reading (dosage) and number of bolts worked is presented.
Specifically, the study showed that production measured in bolts drilled increased from 22 bolts on average up to 80 bolts, and resulted in a reduction in noise exposure from average in dba from 138 to 75 db. While the study is not statistically designed, the results point to the possibility of greatly increased productivity when the inventive noise suppression device is used.
While the effectiveness of the device 10 is increased by including all of the claimed features, there may be specific uses that may achieve adequate sound reduction with fewer sound suppressors, or without the skirting, or with other adjustments which are considered to be within the scope of this invention.
Although the present invention has been particularly described with reference to implementations discussed above, various changes, modifications and substitutes can be made. Accordingly, it will be appreciated that in numerous instances some features of the invention can be employed without a corresponding use of other features. Further, variations can be take the number and arrangement of components illustrated in the figures discussed above. The foregoing description of embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise from disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.
