GB2230728A

GB2230728A - Engine hammer

Info

Publication number: GB2230728A
Application number: GB8908645A
Authority: GB
Inventors: Akira Nagashima; Yoshiki Nakayama
Original assignee: Kioritz Corp
Current assignee: Kioritz Corp
Priority date: 1989-04-17
Filing date: 1989-04-17
Publication date: 1990-10-31
Anticipated expiration: 2009-04-17
Also published as: GB8908645D0; GB2230728B; DE3913426A1

Description

k "ENGINE WMEW'

1 BACKGROUND OF THE INVENTION

This invention relates to an engine hammer.

Electric hammers may be mentioned as machines that are useful for boring holes in the ground or in building structures, or for performing such operations as excavation and ground leveling. Since they utilize electric motors as the driving means, these machines must be connected to an electric power source through an electric cable, which means that a power source must be available in each site where they are used or in the vicinity thereof. This inconvenience has led to a demand for an engine hammer with a built- in internal combustion engine which can serve as the driving means. To data, however, satisfactory measures have not been taken to effectively protect the operator of an engine hammer from the heat that emanates from the exposed internal combustion engine and the vibrations generated by it during operation. Besides this, conventional engine hammers have not been designed to be able to withstand rough handling.

SUMMARY OF THE INVENTION

This invention aims at overcoming the problems experienced with conventional engine hammers. It is 1 accordingly an object of this invention to provide an engine hammer which provides for effective protection of the operator by cutting off the heat from the engine and the vibration thereof during operation.' Another object of this invention is to provide an engine hammer which is easy to handle and which is simple in structure and convenient in use.

in accordance with this invention, there is provided an engine hammer comprising a body cover and a power generation and transmission system formed as a single unit and enclosed in said body cover, said power generation and transmission system including an internal combustion engine serving as the driving means, an engine case section for said internal combustion engine. a forwardly extending base section integrally formed with said engine case section, a hammer crankcase attached to said base section, a hammer crankshaft rotatably arranged within said hammer crankcase, a forwardly extending hammer cylinder member attached to said hammer crankcase and operationally connecting said hammer crankshaft to said internal combustion engine# a tool retainer arranged in the front end section of said hammer cylinder member, and a reciprocating device provided in said hammer cylinder member and operationally connected to said hammer crankshaft. This engine hammer further comprises handles provided on said body cover and designed to be grasped by the operator, and vibration isolators, said power generation and transmission system being supported by said body j 1 cover through said vibration isolators.

Thus, the power generation and transmission system formed as a single unit and including the internal combustion engine, the hammer crankcase, the hammer cylinder member, etc.r is supported by the body cover through the vibration isolators. This arrangement helps to prevent the vibration and heat of the engine from being transmitted toward the operator during operation and to protect the system itself. Thus, in accordance with this lo invention, an engine case section is provided which enables an internal combustion engine to be mounted as it is. This offers a greater degree of freedom in the selection of the internal combustion engine to be used. In addition, the power generation and transmission system which is composed of an internal combustion engine, a hammer crankcase, a hammer cylinder member, etc. is separately prepared as a single unit, so that the production, assemblage and maintenance of the engine hammer are facilitated, and the internal combustion engine is protected from external forces. Furthermore, since this unit is supported by the body cover through vibration isolators, the vibration and heat generated therein are prevented from being transmitted toward the operator. thereby guaranteeing operational safety.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a longitudinal sectional view showing an embodiment of the engine hammer in accordance with this 4 1 invention; and Fig. 2 is a cross-sectional view taken along the line II-II of Fig. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT 5 An embodiment of this invention will now be described with reference to the accompanying drawings. In the embodiment shown, a body cover 1 formed from a hard plastic material or the like encloses an internal combustion engine 2 in the manner described below. The internal combustion engine 2 includes a cylinder 3 containing a piston 5 as well as a crankcase 58. The cylinder 3 and the crankcase 58 rotatably support an engine crankshaft 8 through bearings 6 and 7. Attached to the rear end of the engine crankshaft 8 is a cooling fan 9 which is enclosed by a fan cover 10 and which serves to cool the internal combustion engine 2 during operation by supplying cooling air thereto. Furthery a conventional recoil-type starter 11 is attached to the above-mentioned fan cover 10 such as to be concentric with the engine crankshaft 8. The starter 11 is equipped with a ratchet wheel 13 which operationally engages with centrifugal ratchet pawls 12 arranged on the cooling fan 9. The starter 11 is driven when the operator pulls the outer end of a rope 59 thereof which outwardly protrudes beyond the abovementioned body cover 1. This drives the engine crankshaft 8 through the ratchet wheel 13, the centrifugal ratchet pawls 12 and the cooling fan 9. thereby starting 14 il 1 the internal combustion engine 2.

The internal combustion engine 2 is firmly fixed to an engine case section 4 which is designed to cover the lower half of the crankcase 58. Arranged at the front end of the engine crankshaft 8 is a centrifugal clutch 14. which is of a conventional type and which includes a boss member 16 to which clutch shoes 15 are engaged, a drum 17 on the driven side being arranged concentrically with the boss member 16. The drum 17 is fixed to an input shaft 19r at the front end of which a small bevel gear 18 is formed. Formed integrally with the above-mentioned engine case section 4 is a base section 20 extending forwardly therefrom. This base section 20 rotatably supports the above-mentioned input shaft 19 through bearings 21 and 22. A hammer crankcase 23 is mounted on the upper section of the base section 20. This hammer crankcase 23 rotatably supports a vertically extending hammer crankshaft 24 through bearings 25 and 26. Fixed to the lower end of this hammer crankshaft 24 is a large bevel gear 27 which meshes with the above-mentioned small bevel gear 18 to receive driving force therefrom. Thust the hammer crankshaft 24 is rotated at a reduced speed with respect to the engine crankshaft 8 and the input shaft 19.

Attached to the front end section of the above- mentioned hammer crankcase 23 is a hammer cylinder member 28 in which a large hollow hammer piston 29 is provided in such a manner as to be capable of making a longitudinal reciprocating movement within the hammer cylinder member - 6 1 28. This large hammer piston 29 includes a small hammer piston 30 which is arranged therein in such a manner as to be slidable in the longitudinal direction. This small hammer piston 30 is connected to the above-mentioned hammer crankshaft 24 through a connecting rod 31. The large hammer piston 29, the small hammer piston 30 and the connecting rod 31 form a reciprocating device 57. A tool retainer 32 for holding a tool such as a bit is provided at the front end of the hammer cylinder member 28. This tool retainer 32 includes at its rear inner end a tool stopper 33 which abuts against a front end head 34 of the large hammer piston 29 so as to be reciprocate therewith in the longitudinal direction. Thus, when the hammer crankshaft 24 is rotated by the driving force transmitted thereto from the internal combustion engine 2 through the centrifugal clutch 14, the small bevel gear 18 of the input shaft 14 and the large bevel gear 27, the small hammer piston 30 reciprocates in the longitudinal direction to compress and expand the gas in the airtight space within the large hammer piston 29. which causes the large hammer piston 29 to reciprocate with respect to the hammer cylinder member 28 and repeatedly strike the tool stopper 33 and the tool attached thereto. thereby making it possible to perform boring of holes in the ground or in building structures.

Thus, all the components excluding the body cover 1, i.e., the internal combustion engine 2, the engine case section 4. the base section 20, the hammer 1 crankcase 23 and the hammer cylinder member 28 as well as the bevel gears 18, 27. the large hammer piston 29 and the small hammer piston 301 etc.i form a single unit for power generation and transmission.

Formed in the front upper section of the body cover 1 at a position corresponding to the center of gravity of the engine hammer is a front handle 35. A rear handle 36 is formed at the rear end of the body cover 1. These handles, which are provided in order to enable the operator to hold the engine hammer, are formed integrally with the body case 1. Pivotably supported within the rear handle 36 is a trigger 37 which is operated in order to control the throttle valve (not shown) of the internal combustion engine 2. The front end 38 of the trigger 37 engages with the rear end 40 of an intervenient lever 39 which is also rotatably supported within the rear handle 36. The front end 41 of the intervenient lever 39 engages with a throttle lever 44 which is connected to a throttle valve axle 43 (Fig. 2) of a carburetor 42 of the internal combustion engine 2. The carburetor 42 which is separated from the internal combustion engine 2 is attached to an inner wall 45 of the body cover ll and is connected to the internal combustion engine 2 through an air supply tube 60 which is made of rubber. thereby cutting off the heat and vibration from the internal combustion engine 2 during operation. As shown in Fig. 2, a fuel tank 46 is attached to the inner wall of the body cover 1. This fuel tank 46 is also shielded against the heat from the internal 1 combustion engine 2 by the engine case section 4 disposed therebetween. When the operator pulls the trigger 37 during operationj the throttle lever 44 is operated through the intervenient lever 39, and opens the throttle valve, thereby accelerating the internal combustion engine 2.

The front end section of the body cover 1 supports the hammer cylinder member 28 at the middle section thereof through two semispherical rubber vibration isolators 47 and 48. Further, the single unit for power generation and transmission which includes the internal combustion engine 2, the base section 20. the hammer crankcase 23. etc. is supported by the body cover 1 through appropriate brackets 54. rubber vibration isolators 49. 50y 51 and 52 being provided between the brackets 54 and the body case 1. two on each side. Thus, the body cover 1 which includes the front and rear handles 35 and 306 provided to enable the operator to hold the engine hammer is completely isolated from the abovementioned unit for power generation and transmission by the vibration isolators 47, 48, 49, 501 51 and 52l thereby effectively preventing the vibration and heat generated during operation from being transmitted toward the operator. The reference numeral 53 in Fig. 2 indicates a muffler adapted to muffle and discharge the exhaust gas from the internal combustion engine 2.

The muffler 53 includes an exhaust pipe 55 which, combined with a guide pipe 56 having a larger k 1 1 diameter, helps to forwardly discharge the heated air within the body cover 1 along with the exhaust gas.

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Claims

WHAT IS CLAIMED IS:

1. An engine hammer comprising a body cover 1; a power generation and transmission system enclosed in said body cover 1 and formed as a single unit; handles 35 and 36 provided on said body cover 1 and designed to be grasped by an operator; and vibration isolators 47. 48, 49, 50, 51 and 52; said power generation and transmission unit including an internal combustion engine

2 serving as the driving means, an engine case section 4 for said internal combustion engine 2, a forwardly extending base section 20 integrally formed with said engine case section 4, a hammer crankcase 23 attached to said base section 20, a hammer crankshaft 24 rotatably arranged within said hammer crankcase 23, a forwardly extending hammer cylinder member 28 attached to said hammer crankcase 23 and operationally connecting said hammer crankshaft 24 to said internal combustion engine 2, a tool retainer 32 arranged in the front end section of said hammer cylinder member 28, and a reciprocating device 57 provided in said hammer cylinder member 28 and operationally connected to said hammer crankshaft 24, said power generation and transmission system formed as a single unit being supported by said body cover 1 through said vibration isolators 47r 48y 49, 50, 51 and 52.

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3.

11 2. An engine hammer having a body cover, handles provided thereon and designed to be grasped by the operator, and a power generation and transmission system formed as a single unit and including an internal combustion engine, a hammer crankcase, a hammer crankshaft, and a hammer cylinder member containing a reciprocating device operationally connected to the hammer crankshaft, the power generation and transmission. system being supported by the body cover through vibration isolators.

An engine hammer comprising a body cover and a power generation and transmission system formed as a single unit and enclosed in said body cover, said power generation and transmission system including an internal combustion engine serving as the driving means, an engine case section for said internal combustion engine, a forwardly extending base section integrally formed with said engine case section. a hammer crankcase attached to said base section, a hammer crankshaft rotatably arranged within said hammer crankcase., a forwardly extending hammer cylinder member attached to said hammer crankcase and operationally connecting said hammer crankshaft to said internal combustion engine, a toolretainer arranged in the front end section of said hammer cylinder member, and a reciprocating device provided in said hammer cylinder member and operationally connected to said hammer crankshaft.

4. Any novel integer or step, or combination of integers or steps, hereinbefore described and/or as shown in the accompanying drawings, irrespective of whether the present claim is within the scope of, or realtes to the same or a different inventeion from that of, the preceding claims.

5. An engine hammer substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

Published 1990 atThe Patent Office, State House. 66'71 High Holborn, LondonWC1R4TP. Further copies maybe obtainedfromThe Patent OfficeSales Branch. St Mary Cray, Orpington. Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent, Con. 1187