BOLT HOLDING AND TIGHTENING TOOL

Abstract: A bolt holding and tightening tool for a nut situated on a bolt at an end thereof which is provided with spanner flats and on which the nut can be screwed. The tool has a first grip (3) for coaction with the nut and a second grip (4) for coaction with the bolt and a gear mechanism which distributes an applied torque to the first grip (3) for tightening and to the second grip (4) for holding. The second grip is arranged in a holding member (9) axially movable in a rotatable tightening member (5) having the first grip (3) on the same axis (16), the gear mechanism has an input gear wheel (17) to which is applied the torque, and an output gear wheel (15) connected to the first grip (3). Both gear wheels (15, 17) coact with an internally toothed drive sleeve (23) which surrounds the gear wheels and is rotatable about a rotational axis (27), which is displaced in parallel from the common axis (16) of the gear wheels.

Description: DESCRIPTION Bolt Holding and Tightening Tool Field of the Invention: The invention relates to a bolt holding and tightening tool to which a torque may be applied either manually or mechanically and which is dispo¬ sed for tightening a nut on the end of a bolt or screw with which the nut can mesh and which is also provided with spanner flats. The tool has a first torque-transmitting grip for coaction with the nut and a second torque-transmitting grip for coaction with the bolt. A gear mechanism is arranged there- between to distribute the torque applied to the tool to the first torque-transmitting grip for tightening the nut while the second grip prevents rotation of the bolt. The second grip is arranged in an anti- rotation bolt holder centered in a tightening member rotatable about the holder and provided with the first grip. The bolt holder is axially displaceable in the tightening member for engagement against the flats of the bolt end. The gear mechanism has the tightening member united with a gear' wheel provided externally with teeth and mounted in a housing about an axial line common to this gear wheel and a gear wheel similarly provided with exterior teeth which is nonrotatably united or nonrotatably connectable to a means supplying the torque. The holder is secured againt rotation relative the housing. Description of the Prior Art: Bolt holding means of this kind are known in all essentials from the Swedish Patent 202 098 and the US Patents 2 537 382 and 2 882 773. The means according to the Swedish Patent is in one of its embodiments suited to very special spaces where the height in the longitudinal direction of the bolt is very limited but where the lateral extension of the means is no disadvantage. In other embodiments the means has a width which may be an obstruction to working with it. Both the US Patent Specifications also illustrate means having gear mechanisms making it laterally voluminous. Summary of the Invention The object of the invention is therefore to provide a bolt holding tool of the kind described in the introduction, the gear mechanism of which is improved in respect of making it less demanding with respect to space. The desired result is obtained by the tool being given the characterizing features apparent from the following claim. Brief Description of the Drawing One embodiment of the invention will now be described in detail with reference to the accompanying drawing, on which Figure 1 is a longitudinal section through the tool according to I-I in Figure 3, Figure 2 is a side view of the -tool to a smaller scale, and Figure 3 is an end view of the tool to the same smaller scale and illustrating the torque input end of the tool. Detailed Description of the Preferred Embodiment The tool illustrated on the drawing is formed as an intermediate member between the boIt/nut and an unillustrated means for applying torque to tighten the nut. The torque-applying means may be such as an electric or pneumatic machine or a hand-driven tool. The torque is applied in all cases to a drive sleeve 1 with a square socket 2 accommodating the square driver on the machine or hand-driven tool. The items to which the tool is addressed are not shown, but comprise in every case of a hexagonal nut threadable on the end of a bolt which is also provided with spanner flats. The tool has a first torque-transmitting hexagonal grip 3 for coaction with the nut and a second torque-transmitting grip 4 for coaction with the bolt. The applied torque is distributed to the first grip 3 for tightening the nut and to the second grip 4 for preventing rotation of the bolt. The first grip 3 is arranged in a tightening member 5. The latter is put together from an exterior sleeve 6 having the grip 3 and removably and nonro- tatably retained about the neck portion of an inner sleeve 7 extending into the interior of the tool. The sleeves 6 and 7 are locked to each other with the aid of a set screw 8. The second grip 4 is arranged in an anti- rotation bolt holder 9 centered in the tightening member 5. The tightening member 5 is rotatable about the holder 9, which in turn is axially displaceable in the member 5. More specifically, a locking arm 10 is arranged in the interior of the tool and formed with a hub portion 11 about which the inner sleeve 7 of the tightening member 5 is rotatably mounted with the aid of needle rollers 12, while the holder member 9 has a shaft portion thrusting into a central hole in the hub portion 11 where it is secured against rotation and given axial freedom with the aid of splines 13 on the shaft portion and in the central hole. The end of the shaft portion is acted on by a spring 14 in the central hole of the hub portion 11 , with a bias such as to urge the holder 9 in a direc- tion engaging it with the spanner flats (unillustrated) on the bolt end. The gear mechanism has an output gear wheel 15 for the torque. This gear wheel is illustrated integra with the inner sleeve 7 of the tightening member 5 and is rotatable about an axial line 16 which is thus common to this gear wheel 15, the tightening member 5, holder member 9 and also to an input gear wheel 17, which is non-rotatably couplable to a machine or a hand-driven tool for applying a torque via the mentioned square socket 2 in the outwardly facing end portion of the input gear wheel 17, i.e. the mentioned drive sleeve 1. The input gear wheel 17 is also rotatably mounted on the hub portion 11 of the locking arm 10 with the aid of needle rollers 18. The gear wheel 17 has a journal-like extension forming the drive sleeve 1 which runs in a needle bearing 19 mounted in a housing 20 enclosing the gear mechanism. The holder member 9 is non-rotatable relative the housing 20 with the aid of its splines connec¬ tion with the hub portion 11 of the locking arm 10, which is locked to the housing with the aid of two screws 21, passing through the housing for also connecting it to a lid-like end wall 22. The screws also pass through openings in a portion of the locking arm illustrated as a yoke fastened to the hub portion with the aid of a key and keyway, but can of course just as well consist of a projection integral with the hub portion. The yoke or projec- tion is situated between the gear wheels 15 and 17. In accordance with the invention, the exterior teeth of both gear wheels 15 and 17 mesh with the interior teeth on a drive sleeve 23, which surrounds the gear wheels and locking arm 10 and is rotatably disposed in the housing 20 with its rotational axis 27 displaced parallel to the common axis line 16 of the gear wheels 15 and 17. Thrust needle rollers 25 and radial journal- ling needle rollers 24 are arranged for supporting the sleeve 23 in the housing 20 with its associated end wall 22. Several of the needle roller sets arranged in the housing can be replaced by needle SUBSTITUTE SHEET ( ^ O R M E PI Λ WIPO s roller bearings similar to the bearing 19 if so desired. Between the bearing 19 and the gear wheel 17 there is a spacer ring 26 to complete the axial guidance. The gear wheel 17 is shown non-rotatably couplable to a machine or a hand-driven tool with the aid of the square socket 2, but in other embodi¬ ments it may be permanently joined to such a means for applying torque. OMPI

Claims: CLAIM A bolt holding and tightening tool which may be given a torque manually or mechanically is disposed for tightening a nut situated on the end of a bolt and screwable onto this end which is provided with spanner flats, the tool having a first torque-transmitting grip (3) for coaction with the nut and a second torque-transmitting grip (4) for coaction with the bolt, as well as a gear mechanism which distributes the torque applied to the tool to the first grip (3) for tightening the nut, the other grip (4) preventing the rotation of the screw and being adapted in a holder member (9) centered in a tightening member (5) which is rota¬ table about the member (9) and has the first grip (3) transmitting torque to the nut, the holder member (9) being axially displaceable in the tool (5) for being moved in a direction for engagement with the bolt end, the gear mechanism being adapted with the tightening member (5) and thereby the first grip (3) non-rotatably connected to an* externally toothed gear wheel (15) , there being an axis (16) common to this gear wheel, the tightening member (5) , holder member (9) and a similarly externally toothed gear wheel (17) which is non-rotatably united with, or non-rotatably connectable to, a means applying the torque, the holder (9) being secured against rotation relative a housing (20) surrounding the gear mechanism, c h a r a c t e r i z e d in that both gear wheels (15, 17) coact with an internally toothed drive sleeve (23) surrounding the gear wheels (15, 17) and rotatably mounted in the housing (20) with its axis (27) of rotation displaced parallel to the common axis (16) of the gear wheels (15, 17) . SUBSTITUTE SHEET OMPI

Inventors: LUNDBLAD LENNART, MUNTHER STIG, LUNDBLAD, LENNART, MUNTHER, STIG
Applicants: BAHCO KRAFTVERKTYG AB, AB BAHCO KRAFTVERKTYG
Application year: 1984
Main classification: B25B21
IPC codes: B25B21