Power tool

Abstract: A power tool for tightening and loosening threaded connectors has a link (1) having a link housing (2, 3, 4) and a ratchet mechanism (10) for turning an engaging element (11) so as to turn a threaded connector engaged by the engaging element, a first hydraulic drive unit (21) including a drive housing (22) and a hydraulically movable driving element (24), a second non-hydraulic drive unit (31) including a drive housing (32) and a non-hydraulically moveable driving element (35), a first connection (16, 26, 39) provided on the link housing (2, 3) and on the drive housings (22, 32) of the hydraulic drive unit (21) and the non-hydraulic drive unit (31), so that alternatingly either the housing (22) of the hydraulic drive unit (21) or the housing (32) of the non-hydraulic drive unit (31) can be connected with the link housing (2, 3), and a second connection (8, 27, 40) for connecting the ratchet mechanism (10) alternatingly with the driving element (24) of the hydraulic drive unit (21) or the driving element (35) of the non-hydraulic drive unit (31), so that the driving element (24) of the hydraulic drive unit (21) and alternatingly the driving element (35) of the non-hydraulic drive unit (31) during its movement turns the ratchet mechanism (10) of the link (1) and thereby turns a threaded connector engaged by the engagement element (11) of the link (1) to be tightened or loosened.

Description: The present invention relates generally to power tools for tightening and loosening threaded connectors. More particularly, it relates to such power tools which have a housing, engaging means for engaging a threaded connector to be tightened and loosened, a ratchet mechanism for turning the engaging means so as to turn a threaded connector engaged by the latter, and a drive which acts on the ratchet means so as to turn the ratchet means together with the engaging means and thereby to turn the threaded connector. Such power tools are known in the art. The drive means for such power tools can be hydraulically-operated drive means, for example as disclosed in US-A-5,005,447, US-A-5,029,497, US-RE33951, etc. These tools operate only in conjunction with hydraulic power. There are however many applications where a customer does not require the torque accuracy provided by the hydraulically-operated power tools of this kind or the power provided by hydraulics. Instead, the customer will prefer, instead of using the hydraulically-operated drive powertool which requires more side and overhead clearance, to use a limited clearance tool without having to go into hydraulics. In other instances, the customer seeks a higher torque output than the one provided with its present tool. SUMMARY OF THE INVENTION Accordingly, it is an aim of the present invention to provide a power tool which avoids the disadvantages of the prior art and is a further improvement of the existing tools. The present invention therefore provides a power tool for tightening and loosening threaded connectors, as defined in claim 1. Preferably, the power tool includes the features defined in claim 2. When the power tool is designed in accordance with the present invention, a customer can use the hydraulically-operated drive means in combination with the link means to operate the hydraulically-operated power tool. When needed, it can instead use a non-hydraulically operated drive means in combination with the link means so as to use a non-hydraulically operated power tool. The thusly formed non-hydraulically operated power tool which preferably utilizes a cam also provides an input/output advantage and is relatively inexpensive. Also, it can be powered by manual torque wrenches, cheater bars, manual multiplers, air multiplers, air wrenches, electric wrenches, electric multiplers, impact wrenches, etc, which customers already have in their possession. The present invention provides an economical alternative for the industry to multiply their tools' output force or to convert their square drive tools to limited clearance hex 8-point or 12-point tools. It also permits the customers to start with their tools on hand and to convert the latter to hydraulics if so required. BRIEF DESCRIPTION OF THE DRAWINGS In order that the present invention may be more readily understood, specific embodiments thereof will now be described by way of example only with refernce to the accompanying drawings, in which: Figures 1 and 2 are a plan view and a side view respectively of a link of a power tool in accordance with the present invention; Figures 3 and 4 are a front view and a side view respectively of first drive means of the inventive power tool; Figures 5 and 6 are a front view and a side view respectively of the power tool of the present invention, with the first drive means connected to the link means; and Figure 7 is a side view of the inventive power tool with second drive means connected to the same link. DESCRIPTION OF THE PREFERRED EMBODIMENT A power tool in accordance with the present invention has a link which is identified as a whole with reference numeral 1 in Figures 1 and 2. The link has a housing which is composed of two housing plates 2 and 3 and a cover 4. The housing plates 2 and 3 are connected with one another by rivets 5, and the cover 4 is connected to the housing plates 2 and 3 also by rivets 6. The link 1 is further provided with a drive lever 7 which is turnably received in the plates 2 and 3 through a pivot pin 8 which is movable in grooves 9 provided in facing surfaces of the plates. A ratchet mechanism includes a ratchet 10 which is arranged turnably in the link 1 and has an inner engaging formation 11 which is formed for example as a hexagonal opening, a hexagonal shaft etc. The ratchet 10 has outer teeth 12 which are engageable with teeth 13 of a pawl 14. The pawl 14 is slidingly received in an opening of the drive lever 7 and spring biased by a spring 15 toward the ratchet 10. The link housing or in particular the plates 2 and 3 are provided with connecting means which include openings 16. The power tool further has first drive means which is identified as a whole with reference numeral 21 in Figure 3. The first drive means 21 is formed as a hydraulically operated drive means. The first drive means includes a housing 22 which forms a hydraulic cylinder with a piston 23 reciprocatingly movable in it, and a driving element which is formed as a piston rod 24 connected with the piston 23. Hydraulic fluid is supplied to opposite chambers formed by the piston 23 in the cylinder 22 through hydraulic connecting elements 25 which are connected with a not shown hydraulic fluid source. The drive housing 22 is provided with connecting means which are formed by openings 26. The driving element or the piston rod 24 is also provided with connecting means 27 which can be formed as an opening. As shown in Figure 5, when the power tool in accordance with the present invention operates as a hydraulically-operated power tool, the hydraulic drive housing 22 is connected with the link housing 1 by aligning the openings 16 with the openings 26 and passing corresponding connecting elements through the aligned openings, for example pins 41 and the like. The free end of the piston rod 24 of the hydraulic drive is connected to the pin 8 of the link means 1, for example by inserting the pin 8 into the opening 27. When a hydraulic fluid is supplied into the cylinder of the drive unit, the piston 23 is displaced and displaces the piston rod 24 which in turn turns the drive lever 7 and the pawl 14 arranged on it, the pawl 14 turns the ratchet 10, and the ratchet turns a threaded connector, such as for example a nut, a bolt head, etc., which is engaged by the engaging means 11 of the ratchet. A threaded fastener is tightened or loosened. The power tool in accordance with the present invention has a second drive means which is identified as a whole with reference numeral 31 in Figure 7. The second drive means has a housing 32, a cam 33 rotatable in the housing and formed for example as a double cam, a cam roller 34, and a driving member 35 which is formed for example as a cam rod and displaced during turning of the cam 33 through the roller 34 and a guide ring 36. A compression spring 37 located in a spring sleeve 38 operates as a return spring. The drive housing 32 has connecting means 39, while the cam rod 35 has connecting means 40 formed for example as openings. When it is desirable to use a non-hydraulically operated power tool, a customer disconnects the hydraulically-operated drive means 21 from the link 1 and connects the drive means 31 to the link means 1 by aligning the openings 39 of the non-hydraulic drive means 31 with the openings 16 of the link 1 and passing connecting elements, such as pins 41, through the aligned openings. The connecting element 40, for example an opening at the end of the cam rod 35, is fitted over the pin 8 of the drive lever 7. When the cam is turning, the cam rod reciprocates and turns the drive lever 7 with the pawl 14, so that the pawl 14 turns the ratchet 10, and thereby a threaded connector engaged by the engaging means 11 of the ratchet 10 is turned as well. The cam 33 is provided with third connecting means 41 formed for example as a polygonal (square) projection or opening. The third connecting means 41 can be engaged by an additional tool, such as for example a manual torque wrench, a cheater bar, a manual multiplier, an air wrench, an electric wrench, an electric multiplier, an impact wrench, etc., which a customer has in his possession, so as to turn the cam 33. It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above. While preferred embodiments of the invention have been illustrated and described , it is not intended to be limited to the details shown, since modifications and structural changes may readily occur to those skilled in the art, the scope of protection being determined by the appended claims. Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for suitable applications.

Claims: A power tool for tightening and loosening threaded connectors, comprising engaging means (11) for engaging a threaded connector to be tightened and loosened; ratchet means (10) for turning said engaging means so as to turn a threaded connector engaged by said engaging means (11) ; hydraulic drive means (21) including a drive housing (22) and a hydraulically operated drive provided with a hydraulically movable driving element (24); characterised by link means (1) having a link housing (2, 3, 4), said engaging means (11) and said ratchet means (10); non-hydraulic drive means (31) including a drive housing (32) and a non-hydraulically operated drive provided with a non-hydraulically movable driving element (35); first connecting means (16, 26, 39) provided on said link housing (2, 3) and on said drive housings (22, 32) of said hydraulic drive means (21) and said non-hydraulic drive means (31), so that alternatingly either said housing (22) of said hydraulic drive means (21) or said housing (32) of said non-hydraulic drive means (31) can be connected with said link housing (2, 3); and second connecting means (8, 27, 40) for connecting said ratchet means (10) alternatingly with said driving element (24) of said hydraulic drive means (21) or said driving element (35) of said non-hydraulic drive means (31) when said drive housing (22) of said hydraulic drive means (21) is connected with said link housing (2, 3) or said drive housing (32) of said non-hydraulic drive means (31) is connected with said link housing (2, 3) correspondingly, so that said driving element (24) of said hydraulic drive means (21) and alternatingly said driving element (35) of said non-hydraulic drive means (31) during its movement turns said ratchet means (10) of said link means (1) and thereby turns a threaded connector engaged by said engagement means (11) of said link means (1) to be tightened or loosened. A power tool as defined in claim 1, wherein said non-hydraulic drive means (31) has at least one turnable cam (33) which acts on said driving element (35) of said non-hydraulic drive means (31) during turning; and further comprising third connecting means (41) for connecting said at least one cam (33) to a drive tool, so that when the drive tool is connected by said third connecting means (41) to said cam (33) and turns said cam, said cam acts on said driving element (35) of said non-hydraulic drive means (31) and the latter turns said ratchet means (10) to turn said engaging means (11) and thereby to turn a threaded connector to be tightened or loosened.

Inventors: JUNKERS JOHN K, JUNKERS, JOHN K.
Applicants: JUNKERS JOHN K, JUNKERS, JOHN K.
Application year: 2000
Main classification: B25B21
IPC codes: B25B27, B23P19, B25F5, B25B21, B25B13