GB1573811A

GB1573811A - Hand-held tool

Info

Publication number: GB1573811A
Application number: GB48177A
Authority: GB
Original assignee: REPAPRESS AG
Current assignee: REPAPRESS AG
Priority date: 1977-01-07
Filing date: 1977-01-07
Publication date: 1980-08-28

Description

(54) IMPROVEMENTS IN OR RELATING TO A HAND-HELD TOOL (71) We, REPAPRESS AG, of Hofwiesenstr. 1 8590, Romanshorn, Switzerland, a joint stock company organised under the laws of Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to a handheld tool and is an improvement in or modification of the invention disclosed in the specification of U.K. Patent No. 1468376 hereinafter referred to as the main patent.

Claim 1 of the main patent is as follows: A hand-held tool comprising a pair of pivotably connected lever members, end portions of which provide relatively movable jaws of the tool, resilient means acting between the lever members to bias the jaws to an open or inoperative position and a tubular element disposed between the lever members, the tubular element being selectively inflatable by pressure fluid admitted thereto to generate a force acting through the lever members to effect relative movement of the jaws to a closed or operative position and the end portions of the tubular element being closed by a cap fitted thereover.

According to the present invention there is provided a hand-held tool comprising a pair of pivotably connected lever members, end portions of which provide relatively movable jaws of the tool, inflatable means operatively connected with at least one of the lever members and selectively inflatable by pressure fluid to generate a force acting through the lever members to effect relative movement of the jaws, an inlet channel and an outlet channel to the inflatable means, and a manually operable clamp to control flow of the pressure fluid through each of the inlet and outlet channels.

Advantageously, the inflatable means is constructed either as a hose, or as a bag formed by bonding synthetic sheet material or as a membrane assembly. It is thereby possible for this construction to use specially manufactured bags as well as also constructions in the shape of hoses and membrane assemblies available on the market. This is extremely important for the question of the replace ment part delivery.

It is furthermore expedient to structure the inflatable means for use with pliers so as to be wedge-shaped and thus to adapt it to the shape of the pliers, since the operating volume of the bag can thereby be utilised in optimum manner.

It is furthermore important to provide a handle, which provides a part of one arm of the pliers, which makes it possible to create wider plier arms, i.e. large effective surfaces for the inflatable elements, thus to exert large forces and nevertheless to grip and operate the pliers by hand.

When the tool has two double plier levers, one lever is equipped with a membrane assembly and the other lever is provided with an operating piston. This tool is of relatively simple mode of construction and is therefore relatively cheap to manufacture and is easily accessible for repair, for example for replacement of the drum membrane assembly.

It is furthermore advantageous to provide a housing, which has two rigid limbs constructed as handle and in which an appropriate exchangeable insert is inserted, which is preferably retained by a spring-loaded bolt.

In this manner, a universal pair of pliers can be created, which can be used not only for clamping, stripping insulation, riveting, cutting, but also permits the inserts simply, rapidly and securely to be inserted into the housing constructioT as handle and to be removed from this.

When a metal cover plate is pivotably and detachably fastened to one of the rigid handles and a space exists between this and the metal plate for the reception of an elasticwalled bag, as is advantageously the case, then this bag can be exchanged by one manipulation in a manner analogous with the change of a cartridge. In this manner, it is usually unnecessary to interrupt the use of the pliers for lengthy periods in order to fit a replacement bag.

In a further preferred embodiment, two plier arms, for example a stationary and a movable arm, in the assembled state form several chambers which are bounded by transverse walls extending perpendicularly to the direction of motion of the plier arm. The walls separating the chambers are connected alternately to one or other of the pliers arms and, in at least two of these chambers, inflatable bags are disposed. Inflation of the bags causes the forces exerted by each bag in tending to close the pliers to be additive. Thus, one obtains by simple means and in smallest space a pair of pliers, which exhibit very large closing forces for which otherwise correspondingly large lever ratios and particularly large dimensions would be needed. In the present case, by contrast, the dimensions of these pliers are such as to provide a handy tool which may easily be operated by hand.

It can in that case be advantageous for a further bag, which on inflation exerts an opening force on the plier arm, to be arranged in a further chamber in order to mechanise also the opening and to make the operation of the pliers still simpler.

To give more freedom in the arrangement of the inflatable element and to provide force translators appropriate to the purpose of use, one of the stationary plier levers of the housing is preferably provided with a pivotable double lever, which permits the line of action of the force acting on the movable plier lever to be displaced to an optimum position and accordingly crates lever ratio pliers having a mechanical advantage corresponding to the ratio of the lengths of the respective arms of the double lever.

The pliers gain in mobility and can be carried along without heavy power source, for example on assembly operations on mountains and under water, when the pliers are connected through an actuathing valve directly or additionally through a feed hose with a source of pressurised gas, for example a small pressure vessel. In that case, the small pressure vessel can be provided with a hook-on clamp, which permits this vessel to be hooked on to the belt of a pair of trousers for example.

Embodiments of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 shows a perspective view of clamping pliers provided with an exchangeable insert and with an actuating clamp; Fig. 2 shows a front elevation of the housing of the pliers shown in Fig. 1; Fig. 3 shows an inverted plan view of the pliers shown in Figs. 1 and 2; Fig. 4 shows an exchangeable clamping insert in perspective view; Fig. 5 shows a side elevational view of the actuating clamp; Fig. 6 shows a plan view of the clamp shown in Fig. 5 from above; Fig. 7 shows, schematically, a pair of pliers provided with a compressed gas source which may be suspended from the clothing of the operator of the pliers; and Fig. 8 shows a schematic illustration of a pair of pliers connected directly to a compressed gas bottle.

Referring now to the drawings, a plier housing 30 of synthetic material or of a light metallic alloy for example, is provided with a jaw opening 32 adjacent a clamping tweezer groove 34. A slot 36 for the reception of an inflatable bag is disposed in the upper part of the housing 30. Arranged above that is a passage 38 for an actuating clamp, whik a bore 40 forming a continuation of the slot 36 is adapted to receive a supply hose 49 for the bag 47. A pair of exchangeable clamping tweezers 42 is pushed into the groove 34 from the front or side and is positively retained in shape-locking engagement, for example by a snap detent device (not shown). The pair of tweezers 42 has two clamping cheeks 44 and 45.

Fig. 3 shows an inverted plan view of a tongue-shaped bag 47 intended for introduction into the slot 36. This tongue-shaped bag 47 after being mounted protrudes out of the slot 36 and extends up to the forward point of the tweezer housing 30. At its rear end, it is provided with the supply hose 49, which leads to a compressed gas source (not shown).

By the application of appropriate welding seams, a feed channel 51 for the pressure medium and an outlet channel 52 for the emptying of the bag 47 are formed as shown in Fig. 3. A working chamber 54 is defined between the two channels 51 and 52.

Illustrated in Figs. 5 and 6 is an actuating clamp 55, which is provided with two closing cams 57 and 58. The first closing cam 57on the depression of a key 60 which is part of the clamp 55-is pressed against the pressure of a spring 61 on to the outlet channel 52 and closes this off. During this pivotation, the cam edge 62 forms the instantaneous pivot axis. Through this motion, the cam 58 is raised and the feed channel 51 is opened.

Thus, the inlet or feed channel 51 is opened and the outlet or exhaust channel 52 is closed at the same time. The bag 47 is inflated and the clamping cheek 44 is pressed against the clamping cheek 45. On release of the key 60, the spring 61 moves the key 60 away from the housing 30. The actuating clamp 55 is pivoted about the cam edge 63 and the closing cam 58 closes the feed channel 51 while the cam 57 correspondingly opens the outlet channel 52. The compressed gas now flows out of the bag 47. The clamping tweezers open under the influence of their own resilient bias.

Illustrated schematically in Fig. 7 is a pair of pliers 170 having a working arrangement similar to that described in more detail above.

Its bag or roller membrane is supplied through a supply duct 171 from a compressed gas bottle 173. The bottle 173 can be suspended by means of a hook 174, for example on the belt of the trousers of the operator of the pliers.

In the construction shown schematically in Fig. 8, the compressed gas source in the shape of a small compressed gas bottle 178 is, by contrast with the embodiment of Fig. 7, connected directly with the pliers 176 to be actuated. A control key 179 connected to an actuating clamp serves to control the opening and closing of the pliers, the bag of which is supplied through a pressure reducing valve 180.

The illustrated and described pliers are extremely simple to manipulate, while large forces can be exerted on them. The inserts can be made exchangeable, so that a pair of pliers can be used for clamping, riveting, as shears, for bending, or for stripping of insulation. In splite of it being extremely handy, forces can be exerted, which otherwise arise only with standard models and not with hand models.

WHAT WE CLAIM IS: 1. A hand-held tool comprising a pair of pivotably connected lever members, end portions of which provide relatively movable jaws of the tool, inflatable means operatively connected with at least one of the lever members and selectively inflatable by pressure fluid to generate a force acting through the lever members to effect relative movement of the jaws, an inlet channel and an outlet channel to the inflatable means, and a manually operable clamp to control flow of the pressure fluid through each of the inlet and outlet channels.

2. A tool as claimed in claim 1, wherein the inflatable means comprises at least one tubular element or container element of bonded synthetic sheet material, or a membrane element.

3. A tool as claimed in claim 1, wherein the inflatable means is a wedge-shaped element.

4. A tool as claimed in any one of the preceding claims, wherein the inflatable means comprises at least one inflatable element provided with a fastening member.

5. A tool as claimed in any one of the preceding claims, wherein one of the lever members is provided with a handle.

6. A tool as claimed in any of the preceding claims, wherein the inlet channel and the outlet channel are disposed adjacent each other.

7. A tool as claimed in claim 6, wherein the clamp is provided with two cams.

8. A tool as claimed in claim 7, wherein the two cams are disposed beside one another and so arranged that, on operation of the clamp, one of the cams opens the inlet channel and the other cam closes the outlet channel.

9. A tool as claimed in either claim l or claim 2, wherein each of the lever members comprises a respective double-lever, one of the double levers being connected to an inflatable membrane element and the other to a piston co-operating with the membrane element.

10. A tool as claimed in either claim 1 or claim 2 comprising a housing, which is provided with two stationary limbs, and an exchangeable insert which is retained between the limbs by a spring-loaded belt.

11. A tool as claimed in claim 10, comprising a cover plate so pivotally and releasably attached to one of the limbs as to define between that limb and the metal plate a cavity for the reception of at least one elasticwalled container element of the inflatable means.

12. A tool as claimed in either claim 1 or claim 2, wherein a plurality of chamfers are defined by elements of the two lever members, the chambers being bound by transverse walls which each extend substantially perpendicularly to the direction of motion of the lever members on actuation of the tool, the walls alternately belonging to one or the other of the lever members, and wherein inflatable container elements of the inflatable means are so disposed in respective ones of at least two of the chambers that-on inflation of the container elements-the closing forces exerted by the respective container elements on the lever members are additive.

13. A tool as claimed in claim 12, comprising a further container element so disposed in a further one of the chambers, that on the further container element being inflated -the further container element exerts a force on the lever members which tends to open the jaws of the tool.

14. A tool as claimed in claim 10, wherein one of the stationary limbs of the housing is provided with a pivotably mounted double lever adapted to displace the line of action of the force exerted by the inflatable means on the movable member, thereby to control the force transmission ratio in accordance with the ratio of the lengths of the lever arm portions of the pivotaly mounted double lever.

15. A tool as claimed in any one of the preceding claims, wherein the inflatable means of the tool is connected by way of a pressure reducing valve directly to a compressed gas source.

16. A tool as claimed in any one of claims 1 to 14, wherein the inflatable means of the tool is connected by way of a feed pipe to a compressed gas source.

17. A tool as claimed in either claim 15 or claim 16, wherein the compressed gas

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. of pliers 170 having a working arrangement similar to that described in more detail above. Its bag or roller membrane is supplied through a supply duct 171 from a compressed gas bottle 173. The bottle 173 can be suspended by means of a hook 174, for example on the belt of the trousers of the operator of the pliers. In the construction shown schematically in Fig. 8, the compressed gas source in the shape of a small compressed gas bottle 178 is, by contrast with the embodiment of Fig. 7, connected directly with the pliers 176 to be actuated. A control key 179 connected to an actuating clamp serves to control the opening and closing of the pliers, the bag of which is supplied through a pressure reducing valve 180. The illustrated and described pliers are extremely simple to manipulate, while large forces can be exerted on them. The inserts can be made exchangeable, so that a pair of pliers can be used for clamping, riveting, as shears, for bending, or for stripping of insulation. In splite of it being extremely handy, forces can be exerted, which otherwise arise only with standard models and not with hand models. WHAT WE CLAIM IS:

1. A hand-held tool comprising a pair of pivotably connected lever members, end portions of which provide relatively movable jaws of the tool, inflatable means operatively connected with at least one of the lever members and selectively inflatable by pressure fluid to generate a force acting through the lever members to effect relative movement of the jaws, an inlet channel and an outlet channel to the inflatable means, and a manually operable clamp to control flow of the pressure fluid through each of the inlet and outlet channels.

7. A tool as claimed in claim 6, wherein the clamp is provided with two cams.

source comprises a bottle containing compressed gas.

18. A hand-held tool substantially as hereinbefore described with reference to Figs. 1 to 6 of the accompanying drawings.

19. A hand-held tool substantially as hereinbefore described with reference to Figs. 7 and 8 of the accompanying drawings.