首页
产品
黄页
商标
征信
会员服务
注册
登录
全部
|
企业名
|
法人/股东/高管
|
品牌/产品
|
地址
|
经营范围
发明名称
Hydraulic counterbalance for drill pipes
摘要
申请公布号
US2112254(A)
申请公布日期
1938.03.29
申请号
US19360075529
申请日期
1936.04.21
申请人
STOKES JOHN C
发明人
STOKES JOHN C.
分类号
E21B44/00
主分类号
E21B44/00
代理机构
代理人
主权项
地址
您可能感兴趣的专利
CATHODE-RAY TUBE
BASE UNIT MACHINING METHOD BY ION BEAM MILLING
POLARIZED RELAY
ABNORMALITY SIGNAL GENERATING APPARATUS
GAS LEAKAGE DETECTING DEVICE
PUSH-BUTTON SWITCH
SWITCHING ACTION DISPLAY DEVICE
MANUFACTURE OF ENAMEL WIRE
MANUFACTURE OF ANISOTROPIC CONDUCTIVE FILM
STRUCTURE OF POWER SUPPLY BUS BAR
FITTING DEVICE FOR CEILING DIRECT-FITTED LUMINAIRE
TUBE AND HEAT CONTRACTION TUBE
MEMORY DEVICE
WRITING CONTROL CIRCUIT
SYNCHRONOUS SIGNAL DETECTOR FOR OPTICAL DISK
DIGITAL SIGNAL PROCESSING CIRCUIT
DISK REPRODUCING DEVICE
VERY HIGH-SPEED CCD
SEMICONDUCTOR STORAGE CIRCUIT
MEDIUM SUPPORTING DEVICE AND MEDIUM ACCESSING DEVICE
