US 4,909,419 AGranted

Percussion tool

AssigneeMax Co., Ltd.

InventorsToshio Yamada, Keijiro Murayama, Michiaki Adachi

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Abstract

A percussion tool of the repeatedly operating type includes a housing, a striking cylinder received in the housing for movement therealong, and a driving piston received in the striking cylinder for movement therealong. The striking cylinder cooperates with the housing to provide a switch valve means which is responsive to the movement of the striking cylinder along the housing for selectively interrupting fluid communication between the interior of the striking cylinder and a discharge port and communicating the interior of said striking cylinder with a compressed air source when the striking cylinder is at its lower position to thereby move the striking piston to cause an associated striking driver to strike a driven element and for selectively interrupting the communication between the interior of the striking cylinder and the compressed air source and communicating the interior of the striking cylinder with the discharge port as the striking cylinder is moved from its lower to upper position. Air within that portion of the interior of the striking cylinder between a lower face of the driving piston and a lower end of the striking cylinder is compressed by the striking piston moving toward an ejecting portion receiving the driven element and is supplied to a return air chamber. The air thus compressed acts on the lower face of the piston to urge the same away from the ejecting portion.

Claims8

Dependent claims

A percussion tool of the repeatedly operating type which comprises:

(a) an elongated housing;
(b) a tubular ejecting member extending from a lower end of said housing and adapted to receive a driven element therein;
(c) a striking cylinder having upper and lower closed ends and received within said housing for movement therealong between an upper and a lower position, said striking cylinder being spring-urged into its lower position toward said ejecting member;
(d) a striking piston received within said striking cylinder for sliding movement therealong toward and away from said ejecting member, said striking piston having a striking driver mounted thereto and slidably extending through the lower end of said striking cylinder and being extendable into said ejecting member, said striking cylinder cooperating with said housing to provide an automatic switch valve means which is responsive to the movement of said striking cylinder along said housing for selectively communicating the interior of said striking cylinder with a compressed air source to move said striking piston to cause said striking driver to strike said driven element and for selectively communicating said interior with the ambient atmosphere;
(e) a contact member movable between an upper and a lower position and spring-urged into its lower position where said contact member projects downwardly from a lower end of said ejecting member;
and
(f) a trigger means for actuating said switch valve means so as to communicate the interior of said striking cylinder with said compressed air source, said trigger means including a contact lever manually operable to be moved into its operative position, said contact member being engageable with said contact lever to move said contact lever to said operative position so as to actuate said switch valve.

4 more elements

A percussion tool of the repeatedly operating type which comprises:

(a) an elongated housing having at its lower end portion a tubular ejecting portion adapted to receive a driven element, said housing having at its upper end portion a discharge port;
(b) a striking cylinder having upper and lower closed ends and received within said housing for movement therealong between an upper and a lower position, said striking cylinder being spring-urged into its lower position toward said ejecting portion;
(c) a striking piston received within said striking cylinder for sliding movement therealong toward and away from said ejecting portion, said striking piston having a striking driver mounted thereto and slidably extending through the lower end of said striking cylinder and being extendable into said ejecting portion, said piston having a lower face in facing relation to said ejecting portion, and a return air chamber disposed between said striking cylinder and said housing and communicating with that portion of the interior of said striking cylinder disposed between said lower face of said striking piston and the lower end of said striking cylinder;
(d) said striking cylinder cooperating with said housing to provide a switch valve means which is responsive to the movement of said striking cylinder along said housing for selectively interrupting fluid communication between the interior of said striking cylinder and said discharge port and communicating the interior of said striking cylinder with a compressed air source when said striking cylinder is at its lower position to thereby move said striking piston to cause said striking driver to strike said driven element and for selectively interrupting the communication between the interior of said striking cylinder and said compressed air source and communicating the interior of said striking cylinder with said discharge port as said striking cylinder is moved from its lower to upper position, and air within said that portion of the interior of said striking cylinder being compressed by said striking piston moving toward said ejecting portion and being supplied to said return air chamber, said air thus compressed acting on said lower face of said piston to urge the same away from said ejecting portion.

1 more element

Dependencies are inferred from the claim text.