Magnetic cover remover
A cover removal apparatus in embodiments of the invention may include one or more of the following features: (a) a frame, (b) an electromagnet, (c) a power source electrically coupled to the electromagnet for selectively energizing the electromagnet, (d) means for positioning the electromagnet relative to a cover, the means for positioning coupled to the frame and to the electromagnet, (e) means for loosening the cover, and (f) a hydraulic actuator that forces the second hydraulic ram and the hammer toward the cover to apply a loosening force to the cover with the hammer device.
The present invention relates to the field of lifting devices and more specifically devices for lifting and removing covers. Certain embodiments of the present invention are directed towards a magnetic device for removing manhole covers. Some of these certain embodiments are directed towards a manhole cover remover having an apparatus to loosen a stuck manhole cover.
BACKGROUNDCovers can be used to close holes leading from the street level down to a sewer or other utility connection. The covers allow cars and other vehicles to traverse the road without falling into the hole. Of course, before such holes can be entered their covers must be removed. Such covers are often made of cast iron and tend to be difficult to maneuver because of their size and weight. For example, manhole covers can weigh between 75-400 pounds.
Typically, manhole covers are removed using a long metal rod with a hook at the end. The hook is inserted into an aperture in the manhole cover. A person then physically lifts the cover off the casting that the cover rests on. This can be difficult due to the resting weight of the manhole cover. Further, these covers often stick to the casting thus making it more difficult to lift the cover. To free the covers, typically a person must pound on them with a maul or similar tool. Commonly one person will lift the cover while another person hammers on the cover. The combination of the two forces typically breaks the stuck cover loose. However, injuries to the back, toes, hands, and fingers of the workmen are not uncommon due to the difficulties in handling these heavy manhole covers. Further, there are other safety issues regarding the hook slipping while a person pulls on the cover. During removal, for instance, a person manually removing the cover risks losing balance and falling backwards into traffic if the hook slips while under tension.
SUMMARYA cover removal apparatus in embodiments of the invention may include one or more of the following features: (a) a frame, (b) an electromagnet, (c) a power source electrically coupled to the electromagnet for selectively energizing the electromagnet, (d) means for positioning the electromagnet relative to a cover, the means for positioning coupled to the frame and to the electromagnet, (e) means for loosening the cover, and (f) a hydraulic actuator that forces the second hydraulic ram and the hammer toward the cover to apply a loosening force to the cover with the hammer device.
A cover removal apparatus in embodiments of the invention may include one or more of the following features: (a) a frame, (b) an electromagnet, (c) a power source electrically coupled to the electromagnet for selectively energizing the electromagnet, (d) means for positioning the electromagnet relative to a cover, the means for positioning coupled to the frame and to the electromagnet, (e) a support assembly for the frame comprising, (i) a ratcheted support stem selectively positionable relative to the frame, (ii) a ground support coupled to the support stem at a first end, (iii) a handle coupled to the support stem at a second end, and (iv) a release tab supported by the frame, the release tab selectively restricting movement between the support stem and the frame.
A method for removing a manhole cover in embodiments of the invention may include one or more of the following steps: (a) positioning an electromagnet overtop of a manhole cover, (b) lowering the electromagnet onto the cover, (c) energizing the electromagnet with a power source, (d) loosening the cover with a cover loosening device adjacent to the electromagnet, (e) lifting the electromagnet with the cover, (f) removing the manhole cover from overtop of a manhole cover casting, (g) lowering the electromagnet and cover a distance from the manhole cover casting and deenergizing the electromagnet, (h) releasing a ratcheted support stem having a wheel at one end a ground surface and locking the ratcheted support stem in place with a release tab, and (i) pulling a handle connected to an opposite end of the ratcheted support stem to lift the wheel off of the ground surface.
The following discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from embodiments of the invention. Thus, embodiments of the invention are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of embodiments of the invention. The following introductory material is intended to familiarize the reader with the general nature and some of the features of embodiments of the invention. While the present invention is discussed in detail regarding manhole covers, the present invention is not limited to manhole covers and the inventor fully contemplates that the present invention could be extended to other covers such as storm gates, water caps, and gas caps. Further, while the present invention is discussed in detail regarding the use of a hydraulic ram actuator to lift and remove the covers, other forms of removal, such as a pneumatic lifter, an electric or gas powered motor, and a winch system are fully contemplated without departing from the spirit of the invention.
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Cover loosening apparatus 46 can be powered by hydraulics, such as by an actuator 48, which stores hydraulic pressure. The actuator 48, in turn, can be powered by battery 13, the vehicle's power distribution system, and actuated by toggle switch 30 discussed above. Upon toggling switch 30, actuator 48 forces ram 50 downward causing hammer device 52 to strike cover 34. The force of the impact will hopefully jar cover 34 loose from casting 38. Actuator 48 can hold high pressure fluids or gas such as up to 1000 p.s.i. of nitrogen in the form of an accumulator. The inventors have found that 1000 pounds of pressure works well to loosen cover 34 upon the first impact from hammer device 52.
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Metal plate 64 is slidably coupled to pin 72 that is coupled to electromagnet 12. Hammer devices 52 and 68 can be made of most any material, such as wood or a hard plastic, however, for the purposes of this disclosure both hammer device 52 and 68 are made of a hardened metal. Pin 72 can slidably move through an aperture in metal plate 64 between bumpers 73. However, other various methods of attachment of cover loosening apparatus 56 and cover removal system 8 are contemplated without departing from the spirit of the present invention.
In operation, electromagnet 60 is energized thus holding metal plate 62 and thus hammer device 68 in place. The operator can then lower electromagnet 12 to cover 34 with toggle switch 26. As electromagnet 12 lowers, upper bumper 73 on pin 72 engages metal plate 64 and begins pulling metal plate 64 downward along rod 70. This action causes springs 66 to expand creating a tension force between upper plate 62 and lower plate 64 (
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In operation, when electromagnet 12 is lowered onto cover 34, energized, and ready to lift, an operator lifts release tab 90 of sleeve 98. Release tab 90 is pivots relative to the sleeve 98 about a horizontal axis. Tab 90 is adapted to selectively engage one of the slots of support stem 84 to hold stem 84 in a vertical position relative to sleeve 98. Sleeve 98 acts as a collar encompassing support stem 84. When tab 90 is pivoted out of a slot, ratcheted support stem 84 is permitted to freefall until ground support 86 contacts the surface a distance away from cover 34. Ratcheted support stem 84 self-locks into place relative to sleeve 98, because tab 90 of sleeve 90 that engages one of notches 100 when ground support 86 contacts the ground surface. Cover removal system 8 is now supported at two locations, vehicle 14 and at support assembly 82. The operator can now lift cover 34 via ram 16 and magnet 12 with support assembly 82 supporting the ram frame 18 against the pull of the lifting force generated.
As shown, ground support 86 is a swivel wheel which can freely rotate about 360 degrees about stem 84. Thus, when cover removal system 8 has lifted cover 34 via ram 16 and magnet 12, the operator can get into vehicle 14 and move vehicle 14 with support assembly 82 still supporting the weight and move in any direction in a swivel motion with vehicle 14. However, it is fully contemplated that cover 34 could be manually pushed or pulled out of the way without departing from the spirit of the invention. When ready, the operator can then lower magnet 12 and cover 34, release cover 34, and raise magnet 12. The operator can then release the locking tab (by pivoting it out of the selected slot), grasp handle 88 on top of support assembly 82, and lift ground support 86 off of the ground surface where release tab 90 will engage one of notches 100 on ratcheted support stem 84 self locking in place off of the ground. Support assembly 82 is now ready to travel in a non-supporting fashion.
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Support 114 may be any structure suitable for supporting pivot arm 116. Support 114 can be a dolly 150, such as a two-wheeled dolly 150. As discussed above, support 114 may also be a vehicle 14. Vehicle 14 may be joined to pivot arm 116 and attachment 112. Winch 130, joined to pivot arm 116, may raise and lower attachment 112 relative to manhole cover 190. Power source 140, which may be accessory battery 13 of the vehicle 14, is in operable communication with winch 130.
Pivot arm 116, joined to support 114 may be any extender suitable for positioning attachment 112 toward cover 190. Desirably pivot arm 116 is repositionable to a stored position, which is desired to be vertical near uprights 152. Pivot arm 116 has a proximal end, which may be joined with a hinge to support 114. The distal end of pivot arm 116 may further have a hook or eyelet 124 for connection to connector 126 and cable 132.
Winch 130 may be joined to the distal end of pivot arm 116 via cable 132. Preferably, winch 130 includes a control 144 and wiring. The wiring may join the control to the remainder of winch 130 and may further connect winch 130 to power source 140. Winch 130 should be of suitable size and strength to lift a cover 190 from a street surface.
Power source 140 may be in operable communication with magnet 112 and may be in operable communication with winch 130. The preferred power source 140 is a 12-volt battery, such as those commonly used as accessory batteries in vehicles. Power source 140 provides the power to operate winch 130 and allows use of an electromagnet as the attachment 112.
Cover loosening apparatus 46 is coupled to one of uprights 152 and extends outward from dolly 150. In the event that cover 190 is stuck cover loosening apparatus 46 can be used to jar cover 190 as discussed in detail above.
In operation, a cover 190 may be removed by the steps of: rotating a pivot arm 116 down toward a cover 190. An operator would then connect pivot arm 116 to cover 190. If necessary, the operator would apply power to actuator 48 to send ram 50 downward engaging hammer device 52 forcefully with cover 190, thus hopefully loosening cover 190. The operator can then lift cover 190 upward with winch 130.
Thus, embodiments of the MAGNETIC COVER REMOVER are disclosed. One skilled in the art will appreciate that the present invention can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation, and the present invention is limited only by the claims that follow.
Claims
1. A cover removal apparatus, comprising:
- a frame;
- an electromagnet;
- a power source electrically coupled to the electromagnet for selectively energizing the electromagnet;
- means for positioning the electromagnet relative to a cover, the means for positioning coupled to the frame and to the electromagnet; and
- means for loosening the cover.
2. The apparatus of claim 1, wherein the means for positioning includes a first hydraulic ram coupled to the electromagnet at a distal end of the hydraulic ram.
3. The apparatus of claim 1, wherein the electromagnet is adapted to magnetically attach to the cover when the electromagnet is energized.
4. The apparatus of claim 1, wherein the means for loosening the cover includes a second hydraulic ram having a hammer coupled to the distal end of the second hydraulic ram.
5. The apparatus of claim 4, further including a hydraulic actuator that forces the second hydraulic ram and the hammer toward the cover to apply a loosening force to the cover with the hammer device.
6. The apparatus of claim 2, wherein the means for loosening the cover is a spring hammer apparatus comprising:
- a second electromagnet electrically coupled to the power source;
- a first steel plate capable of electromagnetically coupling to the second magnet;
- a second steel plate;
- a spring coupled to the first plate at a first end and the second plate at a second end;
- a rod extending through the second plate; and
- a hammer device coupled to the first plate at one end and the rod at the opposite end.
7. The apparatus of claim 6, further comprising a connecting pin coupled to the first electromagnet at one end and slideably received by the second plate at an opposite end, wherein the spring is expanded when the first electromagnet is lowered adjacent the cover.
8. The apparatus of claim 7, wherein the rod contacts the cover to loosen the cover from a cover casting when the second magnet is deenergized causing the spring to contract transferring the contraction force to the rod.
9. The apparatus of claim 1, wherein the means for loosening the cover is fixedly attached to the frame.
10. The apparatus of claim 1, wherein the frame is attachable to a vehicle for transporting and positioning the cover removal apparatus.
11. A cover removal apparatus, comprising:
- a frame;
- an electromagnet;
- a power source electrically coupled to the electromagnet for selectively energizing the electromagnet;
- means for positioning the electromagnet relative to a cover, the means for positioning coupled to the frame and to the electromagnet; and
- a support assembly for the frame comprising: a ratcheted support stem selectively positionable relative to the frame; a ground support coupled to the support stem at a first end; and a handle coupled to the support stem at a second end.
12. The apparatus of claim 11, further comprising a release tab supported by the frame, the release tab selectively restricting movement between the support stem and the frame.
13. The apparatus of claim 12, wherein the ground support and support stem are permitted to drop toward a ground surface when the release tab is lifted.
14. The apparatus of claim 13, wherein the ground support can be lifted from the ground surface and positionable relative to the frame when an operator pulls up on the handle of the support stem.
15. The apparatus of claim 13, wherein the ground support is a swivel wheel allowing the support assembly to travel with the cover removal apparatus.
16. A method for removing a manhole cover, comprising:
- positioning an electromagnet overtop of a manhole cover;
- lowering the electromagnet onto the cover;
- energizing the electromagnet with a power source;
- loosening the cover with a cover loosening device adjacent to the electromagnet;
- lifting the electromagnet with the cover.
17. The method of claim 16, further comprising the step of removing the manhole cover from overtop of a manhole cover casting.
18. The method of claim 17, further comprising the step of lowering the electromagnet and cover a distance from the manhole cover casting and deenergizing the electromagnet.
19. The method of claim 16, wherein the cover loosening device is a hammer device actuated by a hydraulic ram.
20. The method of claim 16, wherein the cover loosening device is a spring actuated hammer device.
21. The method of claim 16, further comprising the step of releasing a ratcheted support stem having a wheel at one end a ground surface and locking the ratcheted support stem in place with a release tab.
22. The method of claim 21, further comprising the step of pulling a handle connected to an opposite end of the ratcheted support stem to lift the wheel off of the ground surface.
Type: Application
Filed: May 19, 2006
Publication Date: Nov 22, 2007
Inventor: David Roberts (Andover, MN)
Application Number: 11/437,540
International Classification: E01C 5/00 (20060101);