Drilling tool with a suction device

A drilling tool, including a housing (1), a suction device (14), and at least one gas spring (2) cooperating with both the housing (1) and the suction device (14) and an operational direction of which is parallel to a drilling direction, with the housing (1) having bore (15) for receiving a piston rod (22) and at least a section of cylinder (21) of the at least one gas spring (2).

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to a drilling tool having a housing, a
 suction device, and at least one gas spring which cooperates with both the
 housing and the suction device and an operational direction of which
 coincides with a drilling direction.
 2. Description of the Prior Art
 During formation of bores in a constructional component formed of concrete,
 stone, steel and the like, a cooling medium for cooling the tool and for
 removing drillings is used. In order to keep the working location as clean
 as possible, usually suction devices formed as suction heads are used. The
 suction head surrounds the end, in the drilling direction, region of the
 drill and seals the working location from outside. The suction head has a
 suction nipple with which it is connected with an external
 vacuum-producing apparatus.
 German Utility Model DE-GM 8813719 discloses a drilling tool with a suction
 device and including a gas spring having a cylinder and a piston rod, with
 the cylinder being secured to the housing of the drilling tool and the
 free end of the piston rod being connected to the suction device. The
 piston rod and a surrounding it, sealing region, because of their
 exposure, are subjected to contamination which results not only in a rapid
 wear of the sealing region and in damaging of the piston rod surface, but
 also in malfunction of the entire drilling tool.
 Accordingly an object of the present invention is a drilling tool with a
 suction device in which important parts of the gas spring, which are
 connected with the suction device, are protected from contamination and
 have, therefore, a long service life, insuring a functional reliability of
 the entire drilling tool.
 SUMMARY OF THE INVENTION
 This and other objects of the present invention, which will become apparent
 hereinafter, are achieved by providing a drilling tool including a
 housing, a suction device, and at least one gas spring which cooperates
 with both the housing and the suction device and an operational direction
 of which is parallel to a drilling direction. The housing has an opening
 for receiving the piston rod and at least a section of the cylinder of the
 at least one gas spring.
 The arrangement of the gas spring according to the present invention
 insures that its piston rod and the sealing region, which surrounds the
 piston rod and is associated with the cylinder, are completely protected
 from contamination. In order to prevent the pivotal movement of the
 suction device from its position, in which it is located coaxially with
 the drill, there is provided rotation-preventing means. This means can
 include, e.g., a strip arrange on the cylinder of the gas spring and an
 elongate groove provided in the housing for receiving the strip.
 To provide for a reliable support of the gas spring and a reliable guidance
 of the suction device, the spring cylinder cooperates with the suction
 device, and the piston rod extend into bore formed in the housing and is
 supported against a stop surface provided in the housing bore and facing
 in the drilling direction.
 To provide for a large displacement path of the suction device, which is
 larger than the most possible stroke of the gas spring, advantageously a
 second gas spring is provided, which is arranged in tandem with the first
 spring, with the second spring being connected with the suction device,
 and with both springs being connected with each other by a connection
 element.
 In order to protect the piston rod of the second spring from contamination,
 advantageously, the second gas spring is arranged in a receiving
 sleeve-like member, which projects from the connection element in a
 direction opposite the drilling direction and which is at least partially
 received in a second bore provided in the housing.
 In order to prevent rotation of the second gas spring relative to the
 receiving sleeve, which is fixedly connected with the connection element,
 rotation-preventing means is provided between the second gas spring and
 the receiving sleeve.
 In order to insure a good support of the second spring and a reliable
 guidance of the suction device, advantageously, the cylinder of the second
 gas spring is connected with the suction device, and the piston rod of the
 second gas spring is supported against a stop surface provided in the
 receiving sleeve and facing in the drilling direction.
 In order to be able to insert a drill into the drilling tool, the length of
 which substantially corresponds to the stoke of the gas spring, it is
 necessary to inserethat only the second gas spring can be drawn out, with
 the first gas spring remaining in its drawn-in preloaded condition and
 located in the first receiving bore formed in the housing. This is
 preferably achieved by formlockingly connecting the connection element
 with the housing. For a reliable and easy handling, the formlocking
 connection of the connection element with the housing is formed by a stop
 rim associated with the housing and facing in a direction opposite to the
 drilling direction and a locking element, displaceable perpendicular to
 the drilling direction.
 In order to be able to place the inventive drilling tool in a
 transportation box, it is necessary that not only the first gas spring but
 also the second gas spring can be retained n the drawn-in, preloaded
 position. Advantageously, this is achieved by providing in a second gas
 spring a locking region facing in the drilling direction and in which the
 locking element is formlockingly engaged in the drawn-in, compressed
 position of the second gas spring.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
 A drilling tool according to the present invention, which is shown in FIGS.
 1-3, includes a housing 1, a drive shaft 11, and a chuck 12 for receiving
 a drill 13. The drill 13 has a tubular carrier body and cutting elements,
 not shown, provided at a free, in a drilling direction, end of the carrier
 body.
 The drilling tool housing has two, extending parallel to each other,
 receiving bores 15, 16 having different diameters. Both bores 15, 16 have
 at least one open end facing in the drilling direction. A first opening
 15, which has a smaller diameter, receives a first gas spring 2, with the
 diameter of the first opening 15 substantially corresponding to the outer
 diameter of a cylinder 21 of the first gas spring 2. The gas spring 2 has
 a piston rod 22 which extends into the first bore 15 and is supported
 against a stop surface of the bore 15 facing in the drilling direction. In
 the condition shown in FIG. 1, the cylinder 21 partially projects into the
 first bore 15 to insure a uniform guidance. A portion of the cylinder 21,
 which projects beyond the bore 15, is fixedly connected at its end, which
 faces in the boring direction, with a connection element 23 formed, e.g.,
 as a yoke. In a second bore 16, a receiving sleeve-like member 4, is
 received. The outer diameter of the sleeve-like member 4 substantially
 corresponds to the inner diameter of the second bore 16. The sleeve-like
 member 4 serves for receiving the second gas spring 3, and the inner
 diameter of the sleeve-like member 4 substantially corresponds to the
 outer diameter of a cylinder 31 of the second gas spring 3. The second gas
 spring has likewise a piston rod 32 which extends into the sleeve-like
 member 4 and is supported, at its opposite to the drilling direction end
 against a stop surface provided in the sleeve-like member 4. In the
 position shown in FIGS. 1-2, in which the two springs 2, 3 occupy
 different axial positions relative to the housing 1 of the drilling tool,
 the cylinder 21 of the second gas spring 3 partially extends into the
 sleeve-like member 4 for insuring a better guidance.
 The end, in the drilling direction, region of the cylinder 31 of the second
 gas spring 3 is connected, by a connection element 6, with a suction
 device 14 which is formed as a suction head. The suction device 14 has a
 suction nipple 19 connectable with an external vacuum-producing device,
 not shown.
 A locking bolt 17 projects from an end of the housing 1 facing in the
 drilling direction. The looking bolt 17 has, at its end opposite to the
 drilling direction, a stop rim 18. The distance between the stop rim 18
 and the end surface of the housing 1, which faces in the drilling
 direction, corresponds substantially to a longitudinal extent of the
 connection element 23. The stop rim 18 is formed by an annular side
 surface of a groove surrounding the locking bolt 17. The locking bolt 17
 extends through a hole formed in the connection element 23 and projects
 beyond the connection element 13 in the drilling direction. On its surface
 facing in the drilling direction, the connection element 23 is provided
 with two guide regions 24 which are arranged substantially opposite each
 other and extend along a portion of a circumference of two circles having
 different diameters. Along these guide regions 24, a locking element 5 is
 displaceable between three different locking position in a plane extending
 perpendicular to the drilling direction.
 The locking element 5 has a substantially plate-shaped base body 52, a
 manual handle 51 provided at a first free end of the base body 51, and a
 outwardly opening hole at a second free end of the base body 52. The
 outwardly opening hole is formed of three, arranged one behind the other,
 circular through-openings 53, 54 and 55. The through-opening 55, which is
 located adjacent to the free end of the base body 52, has a diameter
 larger than the diameter of the locking bolt 17. The two other
 through-opening 53, 54 have a diameter corresponding to a core diameter of
 the nut formed on the locking bolt 17.
 In a first locking position, both gas springs 2, 3 are in the drawn-in,
 preloaded position, and the locking bolt 23 abuts the free end of the
 housing 1 facing in the drilling direction. The through-opening 53 of the
 locking element 5, which is closest to the handle 51, formlockingly
 cooperates with the nut provided on the locking bolt 17, and the stop rim
 18 of the locking bolt 17 is pressed against the surface of the base body
 52 of the locking element 5 facing in the drilling direction. The free end
 of the locking element 5 projects into the locking region 33 of the second
 gas spring 3. The locking region 33 is located in a region of the cylinder
 31 of the second gas spring 3 and is formed as an annular groove.
 In a second locking position, the first gas spring 2 is in its drawn-in,
 preloaded position, and the second gas spring 3 is in its drawn-out
 position. The intermediate through-opening 54 formlockingly cooperates
 with the nut provided on the locking bolt 17, and the stop rim 18 of the
 locking bolt 17 is pressed against the surface of the base body 52 facing
 in the drilling direction. The free end of the locking element 5 is offset
 backward with respect to the cylinder 31 of the second gas spring 3.
 In the third locking position, both gas springs 2, 3 are in their drawn-out
 positions. The connection element 23 which is fixedly connected with the
 cylinder 21 of the first gas spring 2 is spaced from the free end of the
 housing 1, and the locking bolt 17 does not extend through the connection
 element 23. The through-opening 55, which is adjacent to the free end of
 the locking element 5, is located coaxially with the locking bolt 17.
 Both gas springs 2, 3 together with the connection element 23, locking
 element 5, and the suction head 14, form a unit attachable and detachable
 from the housing 1 of the drilling tool. To this end, releasable
 connection means, not shown, is provided.
 Though the present invention was shown and described with references to the
 preferred embodiments, various modifications thereof will be apparent to
 those skilled in the art and, therefore, it is not intended that the
 invention be limited to the disclosed embodiment or details thereof, and
 departure can be made therefrom within the spirit and scope of the
 appended claims.